G WA DESIGN GUIDE Construction guidelines for trenches and bunkers at the Great War Association site in Newville, PA.

Central Powers

This resource is intended as a reference tool for all units that wish to build at our site. It is written in a Do-It-Yourself style and contains building information, guidelines and sample sketches to assist units in their design and construction efforts towards a successful project at the site.

The details, dimensions, materials, and so forth contained here represent structures that may be considered as typical for the site. Units are not required to copy structures exactly as shown or described here. These are general guidelines, templates for design, food for thought and may be modified as needed to fit a particular use or on a case-by-case basis.

There are many skilled builders in the GWA and they will not need this guide, although they may gain a tip or two from it. This guide is primarily aimed at the average Joe with some DIY skills. It is hoped that units may obtain some guidance and confidence here to design and construct trenches and structures at the site that meet GWA authenticity, structural and safety standards.

Although the Central Powers and Allied forces each had construction characteristics that were specific to their side, trench manuals of the period frequently reflected similar designs as each side borrowed from the other in the course of the war. In that regard, these guidelines could be considered unilateral for construction at the Newville site.

This guide also contains information on wood stove safety, estimating project costs, instructions for submitting the GWA construction application form and a current list of approved material suppliers and contractors for the Newville site.

- CP Trenchmaster George Walters “Ranger” Sept. 2019CONTENTS:

Part 1 – Basic construction methods & materials

Part 2 – Trench revetment design & sample sketches

Part 3 – Underground structure design & sample sketches

Part 4 – Barbed wire & sample sketches

Part 5 – Wood stoves & GWA fire safety requirements

Part 6 – List of subcontractors & suppliers

Part 7 – Preparing a cost estimate for the project

Part 8 – Completing the GWA construction application form

Part 9 – Future Addenda

GWA DESIGN GUIDE - CENTRAL POWERS

Part 1 – Basic construction methods & materials

During the Great War, trench revetments and bunkers were often constructed in fast order using the almost unlimited manpower available and using materials gained locally. These structures frequently were thrown together quickly, viewed in the short term and often only built to last for weeks or months. At our GWA site we are faced with a unique challenge to replicate Great War structures but do so in a way that will last for years to come, rather than just for months.

This can be accomplished using modern means, methods and materials in combination with materials that would have existed during the war. Examples include using pressure-treated lumber in foundations, rubber roofing material for waterproofing applications, and modern metal panels when none of these are exposed to view. Sample design drawings in this document show how such materials can be used in an unobtrusive manner to support the visible structure where period correct materials are used.

The boys of 1914-1918 built everything using hand tools and muscle but we have the advantage of using modern power tools and generators. A small crew can accomplish a fair amount of work in a short time.

Building trench revetments and structures at our site is not a GWA requirement nor should be. It is a unit decision whether to build and this is of course subject to the unit’s available funds and manpower. This guide is intended for those units who are able to add to the infrastructure at their position at the site.

Some units emulate the late war 1916-1917 battlefield look when trenches were generally just rough ditches and not revetted. Sandbags take the place of revetments in many cases. This is historically correct for the time period we are usually portraying at Newville. But this approach may lead to continuous maintenance

issues for the unit such as repairing trench erosion, weed control, constant sandbag replacement, and this should be taken into consideration for any unit’s long range plans. This maintenance effort may exceed that of building new in the long term.

Some units may be somewhat intimidated by building at the site and it is hoped these guidelines and instructions will help turn “difficult” into “easy.” Units who build at the site are often surprised at how much a crew can accomplish in a few days.

The two basic building components for most structures at our site are rough-sawn (i.e. sawmill) lumber and galvanized corrugated metal. Let’s take a look at both of these materials.

LUMBER: During the war, sawmills were set up in the field behind the lines to meet the demand of the army. These mills ran continuously producing vast quantities of sawn lumber needed by the troops.

“German troops saw tree trunks in the Argonne, for use in dug-outs and trenches.”

Fortunately, there are a number of sawmills operating in the vicinity of our

Newville site and rough sawn lumber is readily available. Some suppliers will even deliver to our site. While no lumber is cheap, the cost of sawmill lumber is relatively inexpensive when compared to the cost of dressed lumber available from retail outlets.

The types of rough sawn wood used most frequently at our site are Red Oak and Hemlock. Both of these species have similar rot resistant qualities and are generally available from the local sawmills. Oak is slightly more expensive and somewhat harder to work with (cut and nail) in the field compared to Hemlock but both species are widely used. Both have high structural strength and load carrying capabilities.

Other species that may be available include Black Locust, which has superior rot resistance but can be difficult to find especially in large sizes. Posts from Locust logs with bark on or off are sometimes used in exterior applications. White Oak similarly has superior rot resistance but it is very expensive. Pine is less expensive than any of the above but any pine has very low rot resistance and this species should be avoided unless used in dry interior applications that are not exposed to the weather. Units need to choose sawmill lumber types carefully depending on a balance of their needs, application and budget.

Fresh cut sawmill lumber generally has high moisture content and some shrinkage can be expected to occur over time, typically about 10-15%. Builders should take this into consideration for their designs. For example, planks set tight against each other when green may develop a half-inch gap between boards when dry. This is usually not a great concern and even desirable in some cases such as duckboards where the gaps allow for quick drainage. Green sawmill lumber generally requires a good bit of air-dry time before this shrinkage stops, sometimes measured in months.

One other point about rough sawn lumber: Almost any species of wood when placed in direct ground contact will typically last only a few years, 4-6 at best, before rot sets in. After that, the decline may occur very rapidly. It is therefore recommended that modern pressure-treated lumber be used in any application

where there is ground contact. It is not difficult to conceal this modern material from the eye as shown in many of the sketches in this document. Typically pressure-treated materials are used for foundations and then covered and concealed with other materials such as rough-sawn lumber.

It is also a common misconception at the site that simply covering the back of rough sawn lumber with tar paper (asphalt-impregnated felt these days) will protect the lumber from ground moisture. This is not true. This material quickly degrades in this application and this practice should be avoided at all costs. Tarpaper is period correct and is a suitable material to use at the site in the correct application but it should not be used for protection against soil contact. It is not meant for that purpose.

CORRUGATED METAL: The use of corrugated steel or tin panels dates back to the late 1800’s and this material was widely used by both sides during the war, particularly by the British troops, and utilized both in the trenches and in the construction of bunkers.

Corrugated metal panels that are very similar in design to what was used during the war are readily available from suppliers including a roofing supply company located in Newville who can deliver to our site.

Although the width and pitch of the corrugations in period photographs varies, a close approximation of period-correct corrugated metal is the 2½ inch rib galvanized corrugated metal panels that are manufactured today. These bright-finished panels will oxidize over time and gain a dull patina, not unlike

the original dull galvanized sheen of metal panels of the period.

The use of “modern” metal panels, often flat with a straight ribbed design offer a less expensive alternative (e.g. ABX type roofing “seconds” metal panels are roughly half the cost of corrugated panels per square foot) in applications when the tin will be hidden from view, for example as structure lining prior to backfill.

OTHER MATERIALS:

Nails should be hot-dipped galvanized common nails to insure longevity when exposed to weather. Interior nails may be non-galvanized. A general rule of thumb for sizing is that 2/3 rd’s of the nail length should be used for penetration into the lower substrate. (e.g. 1 inch thick duckboard nailing should be 10d min.)

Wood screws cannot be avoided in many building applications but modern wood screw types and heads that are not slotted should be driven deep into the wood or obscured in some other manner when at all possible. Only slotted screws are correct to the period.

Galvanized roofing nails or self-tapping roofing screws (where hidden) can be used to fasten metal sheets. Roofing screws with rubber washers should be used to fasten metal panels where waterproofing is desirable such as in roofing.

Lag bolts, carriage bolts and other such connectors should be hot dipped galvanized with a dull finish.

Hardware such as hinges, latches and the like is often hard to period replicate in a cost effective manner. There are antique repro hardware suppliers on the web but their products are frequently costly. Avoid any modern “bright” and plated finish type hardware, opting instead for wrought iron gate-style hardware at the very least. Flea markets are occasionally a good source for old hardware items.

Tarpaper (asphalt impregnated felt) has several uses and should be at least #15 for any above-grade moisture protection (between wood and metal panels for example) and #30 for any exterior wrap. Exterior wrap should be fastened with wood battens for a period correct look. No manufacturer’s marks should be visible. As mentioned previously, tarpaper should not be used in direct contact with the ground.

Rubber roofing is frequently used for adding a waterproof membrane to structure roofs and trench walls. Care must be taken to properly seal seams with appropriate glue and special fasteners should be used, but this product is relatively easy to install, not expensive, and available for purchase from our site caretaker.

Concrete blocks are occasionally used for foundations and structure walls. Visible block walls should be parged (i.e. surfaces coated with mortar) to conceal the look of modern masonry. Mixing mortar at the site requires large amounts of water, is labor intensive and should not be underestimated as a simple operation.

Concrete or stone pavers, generally 2 inches thick are frequently used for foundation support, leveling and particularly at/for load bearing points on grade.

Rebar stakes, typically ½ inch dia. x 1 foot long should be used to anchor structure foundation members. Otherwise the structures will likely move when backfill is placed against them. This may be a minor factor for trench revetments but may become a major factor for underground structures such as bunkers.

Asphalt based sealers or Copper-Green wood coating, both available at retail outlets, are useful for coating sawmill lumber used in foundations, such as the ends of posts, and will add longevity to the wood.

Metal flashing is useful for sealing exterior metal panel corners and joints prior to backfill. Easy to install.TOOLS AND EQUIPMENT: The following is a typical list you would need for construction at the site. Most recommendations are common sense. Some have been learned from experience.

Portable generator (at least 3000-3500 watt power)Contractor grade extension cords (lawnmower type cords will trip the breaker more frequently)Power tools (circular saw, reciprocating saw, drill, impact wrench for lag bolts, etc.)Sawhorses, stepladder Carpenter Speed Square, framing square, measuring tapesFour-foot level Line level (for foundation grades) Hand tools for timber work (hammers, hatchets and the like)Bar clamp or C-clamp(s) for fastening woodSocket set (for lag or carriage bolts)Earthwork tools (shovels, picks)Tin snips or electric shears (for metal panel work)Sledgehammer (for driving rebar pins)

It may seem overkill to list tools and equipment but the instances where a crew is shut down while somebody has to run into town to pickup a needed tool are not infrequent. Make a careful list appropriate to your project beforehand. Battery-run drills are very useful but often wear down quickly drilling into or through sawmill lumber (thicker and greener than the dressed lumber available at stores) so be prepared and bring plenty of extra batteries.

STOCKPILING MATERIAL: When receiving and stockpiling wood materials at the site make sure that all sawmill lumber is placed on wood spacers (“stickers’) to keep the lumber spaced and well above any

ground contact. Fresh sawn lumber generally contains about 15% moisture so it may resist the elements for a short period but should be covered for extended periods of time. Stockpiled pressure-treated lumber is subject to twisting and warping if exposed for too long. Metal panels need no cover but may be useful to cover the lumber stockpile.

Materials should be stockpiled in locations that do not impact mowing during the summer. Make sure any and all materials are stockpiled or moved out of the combat zone if construction cannot be completed before the spring or fall event at the site.

SCHEDULING: Before you plan a worktrip to the site be sure to check the GWA schedule. Occasionally events from other time periods take place during the summer months and worktrips are not allowed on those dates. It is a unit responsibility, not the Trench Masters or any others, to check for any date conflicts.

THE SPEED SQUARE

Try square

The most common use of the Speed Square is to mark square lines at precisely 90 degrees to the board's edge. This job is greatly simplified by the fact that the tool has as a lipped fence running along one edge, which allows you to quickly—and accurately—hold the tool against a board's edge while marking lines along the square's side. Being able to quickly draw square lines is particularly useful for jobs that require repetitive, accurate markings, such as cutting floor boards and trimming ends of sawmill lumber.

Miter square

Because the Speed Square is a right triangle, its long, diagonal edge is machined precisely at 45 degrees to the tool's fence. Just press the fence tight against the board and mark along the square's diagonal edge to draw a precise 45-degree line, useful for items like knee braces and trim.

Protractor

Reading, laying out and marking angles is frequently needed for revetments and structures at our site and the Speed Square has degree graduations stamped along its diagonal edge, so reading and marking angles is made easy. At the corner of the square, near one end of the fence, is a pivot point. Along the diagonal edge are lines, each representing one degree, ranging from zero to 90. To mark a particular angle, let's say, 15 degrees, simply hold the pivot point against the board, and then adjust the square until the 15-degree graduation aligns with the edge of the board. Now draw a line along the square opposite the diagonal edge.

The Speed Square has separate graduations for marking common and hip and valley roof rafters but this feature is not used for our purposes.

Saw guide

One practical use of the Speed Square is not as a square at all, but as a straightedge guide for a portable circular saw. In fact, there's no better, quicker way to crosscut lumber than with a Speed Square: Place the square flat down on the board, with its fence tight against the board's edge. Slide the saw shoe up against the square, and make the cut. Because the Speed Square is thicker than a framing square or combination square, the saw is much less likely to ride up on top of the square. That increases both accuracy and safety.

CONSTRUCTION DRAWINGS

There are several standard “views” used in construction drawings for the building trades and they are described below. It is helpful to know these terms for reading drawings and when making them. Drawings that are submitted for GWA construction should state the type of view.

Plan View (such as floor plan) is a view from above, the most fundamental architectural diagram.

Elevation is a view of a building seen from one side.

Section (or cross-section) represents a vertical plane cut through the object.

Isometric view is a three dimensional view, keeping all the elements in scale

Part 2 – Trench revetment design & sample sketches

“Stellungsbau – The Construction of Field Positions” issued by the Prussian War Ministry, Berlin, 1916 included this profile sketch of the basic fire trench. (British translation of the German document)

The Stellunsbau manual states “Width and depth of trenches must be in the right proportion to each other. Trenches that are too wide or too shallow do not afford sufficient cover. Trenches that are too narrow hamper traffic and are liable to be blocked by falls of earth. Trenches that are too deep require a high firestep, which may be difficult to reach quickly, and, if the water level is near the surface, necessitate high built-up parapets, if they are not to be waterlogged.”

Although our trenches are modern-built these basic principles still ring true and should be followed as closely as practicable. The GWA Site Regulations state that trenches are to be a minimum of 6 feet deep (not including the parapet) and at knee level shall be no less than 3.5 feet wide and shall not exceed 5 feet in width. These measurements are not unlike those in the above period sketch.

There are a number of ways that revetments may be constructed at our site using different materials. They range from simple structures with limited lifespan to heavy-duty structures that may last decades. The degree of simplicity or complexity varies and the design sketches that follow range accordingly.

Here are some revetment terms used in this guide: Posts are the vertical timber members used to support trench walls. Beams or top beams are the overhead braces between posts. A foundation member is the wood support or assembly in contact with the ground. A complete trench support assembly including foundation member, posts and top beam is called a truss. Duckboards are the floor planks and the firestep is self-explanatory. The parapet (forward lip of the trench) may be constructed of earth as shown above but sandbags usually take the place of earth for the trench parapets at our site. The parados (rear lip of the trench), which was built up for protection from artillery fire during the war, is frequently not utilized at our site and is therefore not shown in any drawings here.EXCAVATION: In general all trench excavation should be dug deeper and wider than the dimensions of your revetments. The extra depth is essential as it is easier to fill to bring the bottom up to your grade, rather than pick and cut to get it lower. A minimum excavation depth of 7 feet is recommended. The excavation may need to be several feet wider than the width of your structure in order to be able to work on the exterior face. Take these factors into consideration when planning the excavation needs for your revetments.

Other factors in trench excavation are (1) where to stockpile the excavated material during construction and (2) after the structure is completed and backfill is placed, there may be spoils left over that need to be placed and spread on the site. You will need to work closely with your excavator to address these needs, often overlooked during the planning stage. Revetment construction should begin immediately after excavation. Rain at our site can quickly erode recently dug trenches and you may have some considerable hand digging to do as a result.

GENERAL CONSTRUCTION: Trench revetments are generally built on-site but may be pre-fabricated for later assembly at the site or a combination of both. There are a number of ways to fabricate revetments. Here are a few general guidelines that are pertinent to almost any type of revetment construction.

1. Check the bottom grade of your trench excavation before you begin. The grade should be reasonably level. If there is a significant grade change you may have later problems - the foundation may go down easily enough but major difficulties may occur when you try to line up and button things up on top. Take this into consideration in any construction with an uneven grade change, along with the possibility of having to build a sloped section (may be slippery when wet) or building steps (could be a tripping hazard, especially at night) to accommodate the grade change. A line level or a straight 2x4 with a 4-foot level atop it are useful for checking grade.

2. Minimize the bracing span. One key feature common to most revetment designs is the support system of posts and the need to keep the distance or span between them at a minimum. Three feet or less is recommended. If you go beyond 4 feet span for these supports you will probably experience some bulging inward between posts over time due to soil pressure. These stress points may eventually fail. With every rain or freeze/thaw at Newville the site material expands, shifts and steadily marches toward the point of least resistance. This lack of sufficient post spacing is probably the main cause of revetment problems at the site. Do not shortchange the spacing.

3. Try to construct any wood revetment framing on level ground. It is far easier to construct your framing or trusses in a work area above the trench than to “stick-build” it as you go along, down in the trench. Timber and truss assemblies completed on top can be lowered into the trench fairly easy.

4. Use temporary bracing to hold the revetment framing in place. Check the plumb of vertical posts using a 4-foot level, and once leveled, secure members in place with 2x4 temporary braces. Leave nail head exposed for easy removal after the siding/flooring is placed. The braces can be recycled later in the project (e.g. duckboard supports, etc.)

TRENCH EXAMPLE 1: This is perhaps the simplest and most cost effective design here and is backed by many period photos of similar construction on both Allied and CP sides. It is easy to build with a minimum of materials. The downside is that it may only last a few years and then will need to be rebuilt.

Wooden posts of 3-inch or larger diameter or square 4x4’s are driven or dug into the ground at 3-4 foot intervals. Standard 27 inch wide corrugated metal panels are secured to the posts, and backfill is then shoveled into the space to create a built-up firestep. Sandbags are used to reinforce and line the trench walls.

The key to this type of construction is to use rot-resistant lumber (such as Locust) for the posts or treat other lumber types with a preservative coating for the portion of wood to be buried if you wish any kind of longevity at all. The embedded section of wood will deteriorate very rapidly if you don’t. The sandbagged walls should be tapered back for maximum stability.

This construction will probably last 2-3 years at most, after which time it will need to be rebuilt, especially the sandbagging along the walls but it offers an inexpensive alternative when time and materials are a factor.

Note: Place metal panel joints/overlaps behind post locations. Overlap metal sheets by several inches. TRENCH DESIGN 2: This type of open revetment utilizes a tie back system in which the revetment support posts are attached to buried deadmen via heavy wire or cable. This system secures the walls in place and prevents the walls from movement due to earth pressure, and thereby does not require overhead support members in the trench. The advantages are an open top trench that may facilitate grenade throwing and the

like. The down side is that additional excavation or extensive hand digging is required to bury the deadmen and wire/cable after the structure is in place.

Open top trenches of the period as shown in this photo generally did not have a tie back system. However, they were not meant to last as long as our revetments at Newville. Adding a tie back system to open top style trenches will help insure a much longer life span.

The buried deadman can be a 2-3 foot length of 4x4, 4x6, a short log section or similar material of sufficient mass to resist being pulled through the earth. Steel stakes are not recommended for deadmen.

Deadmen do not need to be attached to every post in the trench revetment. Usually an attachment to every 2nd or 3rd post is sufficient depending on spacing between posts.

The tieback trench wire/cable needs to be completely buried at the site for safety reasons. Minimum of multiple strands of heavy duty galvanized wire (9 gauge or stronger) or ¼” steel cable is recommended for this application. Check manufacturer’s load strengths for this material, which is readily available by the foot at retail outlets.

NOTE: Foundation details, wall types, duckboards, etc. for this and all other revetment frames are discussed in more detail later in this section.TRENCH EXAMPLE 3: This design uses a truss assembly with straight vertical walls, 90° angle cuts and 4x4 lumber for ease of construction and economy. The 4x4’s are attached using 20d nails or lag bolts (better). The right angle cuts are easy to make in the field. The recommended span between posts of each truss assembly is 30-36 inches when using 4x4 lumber. Note that the foundation member is pressure-

treated; the posts and top beams are sawmill lumber. This design may be particularly useful for communication trenches.

NOTE: Foundation details, wall types, truss plates, duckboards, etc. for this and all other revetment frames are discussed in more detail later in this section.

TRENCH EXAMPLE 4: This design uses heavy-duty 4x6’s in the trusses and requires angle cuts. The completed truss is somewhat heavy to move about and set up but it offers good stability and endurance for a long-lasting revetment truss. The outward lean of the posts is very typical of the period, offers better resistance against the soil pressure and adds room at shoulder height for maneuverability.

A carpenter’s speed square makes cutting angles in the field a relatively easy task. All the angles for posts and top beams will be identical, such as 9° for the design shown above.

This photo shows a revetment system that incorporates several features from examples 3 and 4.

The main components of the truss, posts and beams are 4x6 rough sawn lumber.

The posts are cantilevered outward as in example 4. The top beams are attached with 1x6 truss plates. The duckboards are set on pressure-treated 4x4’s, which are 24-30 inches on center.

The bottom members are set on 4-inch concrete blocks to give even greater protection against moisture from ground contact.

Since this is a communication trench revetment, no firesteps are needed and the opening at the top of the trench walls is closed in with 1x boards.

The top boards also offer greater stability to the revetment system.

This photo shows a rough-sawn sawmill post that was placed directly against the ground with no protection.

Moisture has entered the post through the end grain, worked its way up the post and rotted it out for several feet, even splitting the post at the bottom.

This oak post was installed new just 7 years prior to the photo.

Be sure to take extra care in your design to prevent any sawmill lumber from direct ground contact. This is what may happen when you don’t.

TRENCH EXAMPLE 5: This design is similar to 3 and 4 above but the wood planking for the walls is installed on the interior side of the truss framing, and only the posts facing front are cantilevered out. Although there is some loss of room within the revetment as a result, the air space between the exterior tin facing and the interior wood planking will insure that the boards remain dry and will last for a long time.

Summary: As shown in these 5 design sketches, there are a number of ways to frame and construct revetments. Parts of one design can be incorporated into others, mix-and-match, for a system tailored to each individual unit’s needs.

Units should consider the “look” they wish to achieve, the amount of effort (labor in the field) needed, and of course the budget for raw materials and excavation. As with many things, if you shortchange the design at the start, there may come hell to pay a few years down the road.

REVETMENT WALL TYPES: Below are several construction sketches of typical revetment wall types that are frequently used at our site. Some units may prefer corrugated metal panels; others wood planking, or a combination of both.

In Sketch A corrugated panels are used and installed from the bottom up. Use a 4-foot level to insure the top edges of the panels are plumb and overlap the next panel up by at least one rib of the panel. Corrugated metal sheets are generally 27 inches wide (for 24 inches coverage) to allow for this overlap. Likewise, overlap metal sheets horizontally by several inches.

In Sketch B wood planking is nailed on the exterior side of the posts. Metal panels are recommended to protect this planking from soil contact. Rubber membrane may also be used but there will be some moisture buildup between the rubber and wood and thus this material does not protect the wood as well as metal. Since these metal panels will be hidden from view, modern panels may be used.

Modern metal roofing panels are considerably cheaper than the corrugated panels, so the cost per square foot whether you use corrugated panels or sawmill planking together with modern metal panels is almost equal. There is some extra labor involved in the latter, but it is generally not significant for comparison sakes.

In either case, allow for room to work behind the revetment wall to install this material when specifying the needed width for excavation. After installation of the siding material, and anchoring of the foundation system, backfill can then be placed.

Slabwood: Another material that may be useful for revetment or structure walls is slabwood, the exterior face of a log that is cut off during the milling process. Since it is considered waste material by sawmills and often sold for firewood, it frequently can be purchased very economically. Sometimes the cost of delivery to the site is as much as the cost of the material. Slabwood has the bark still attached and over time some of the bark may detach and fall off but this is generally not a problem. The main downside of using this material is that these “planks” come in random widths, lengths and thickness and that must be taken into consideration for your construction. Slabwood is usually fastened with 4 to 6 in. galvanized nails and should be overlapped in shiplap fashion as shown below due to the random nature of the widths.

Wattle: Wood wattle or wicker (stakes interwoven with branches) used for revetment walls is frequently seen in period photos but this is not used much at our site. Although the look is extremely authentic, the process of making wattle panels can be problematic. It is labor intensive and difficult to obtain the fresh saplings ideally needed. The completed product may only last a few seasons before rot begins to set in.

During the war the nearby forests supplied endless material for wattle but we can’t exactly go stripping the woods around our site at Newville, so material availability can be an issue. Small areas for effect are doable however.

Instead of fresh-cut wood, older cut saplings (such as those cut off-site) can be brought to the site and soaked in water for 24-28 hours to make them pliable again. A temporary water trough in the field can be easily made from a tarp draped over concrete blocks or logs on all four sides, for example.

The branches are simply worked or woven around the vertical stakes, starting from the bottom up

The vertical stakes should be the strongest (thickest) wood members of the panel and should be set about 2-3 feet apart.

These panels of wattle were used in direct contact with soil to hold back the ground during the war. That practice is not recommended if you want to have any longevity at all. It is recommended to separate the panels from ground contact with a barrier so that air gets around the wattle. In this fashion the panel may last for several years.

Wattle panels may be pre-fabricated to size to fit in between revetment trusses as shown here or attached to the interior face of your revetment system.

FOUNDATIONS: The most important component of any revetment truss system is the foundation timbers that are used. This is the first part of the system that generally fails when not constructed properly or of the right materials. In the trench design sketches previously shown, pressure-treated 4x4’s are used. Sawmill lumber is NOT recommended for foundations. As mentioned previously, sawmill lumber will begin to rot within a few years with direct ground contact.

There are a number of ways to attach posts to the foundation timbers and two examples are shown here. In Sketch A, the posts are either toe-nailed to the bottom timber or secured with galvanized lag screws. Nails are easier to install typically when constructing in-place at the bottom of the trench but lag screws give a stronger bond. Lag screws may be especially important when building trusses on top and then lowering into the trench.

In Sketch B the posts are set on 2” inch thick stone or concrete paving blocks and the bottom brace is attached laterally. Note: The end grain of the post is highly susceptible to moisture and will begin to rot even when set off the ground in this fashion. The post ends should be treated with bitumen or wood preservative.

It is recommended to secure your revetment foundations into the ground; otherwise they may move or “walk” when backfill is being placed against the revetment walls, sometimes with disastrous consequences. Steel rebar stakes one-foot long are useful for this application. Stakes are driven through the bottom member into the ground with a maul hammer or sledgehammer, either through a pre-drilled hole in the foundation member as shown or with a strong attachment to lateral members such as in Sketch B. Spacing of stakes is determined by the structure (e.g. two per truss.)

DUCKBOARDS: Floorboards are usually one-inch thick sawmill planks. Care must be taken to insure the spacing between support members below the boards is not greater than 2 to 3 feet on center. Otherwise you will have some sagging and the boards may break over time. Broken duckboards are a constant problem and safety issue at our site. If your trusses are spaced further apart, you will need to add additional support members for the planking in-between the truss spacing.

Duckboards may be placed running with the trench as shown in Sketch A, or laterally (cross-wise) as shown in Sketch B. Here the boards are placed on 2x4 pressure treated runners spaced at 24-inch centers. The advantage of the former is ease of construction. The advantages of the latter are that these shorter boards may be replaced more easily, are less likely to sag, and give better traction when trenches are wet. Both are shown in period photos.

1x8 boards are shown in the sketches above but any width (e.g. 1x6, 1x10) of planking may be used. 8d galvanized common nails are recommended to fasten one-inch duckboards. Cut nails may be used for a more authentic “look” but they will rust out much quicker than galvanized common nails and may be a pain in the butt to remove if and when you have to replace boards, so bear that in mind.

Duckboards should have a gap between each board to allow drainage. A large nail is useful as a spacer between boards when nailing. If your sawmill lumber is still green, some shrinkage will occur naturally.

Look at the end grain of boards and install with the grain pattern facing down as shown below to reduce any board warping (i.e. toe-catchers) that may occur over time.

TOP BEAMS: Revetment trusses need strong reinforcement across the top of posts to resist the soil pressure that is exerted on the revetment walls. This pressure will cause revetment walls to collapse inward over time without this support bracing no matter how strong your posts are.

The beam attachment at the top of trusses can be done in a number of ways. A cross member of 2 inch thick lumber can be nailed to the tops of posts (good), truss plates can secure a member between posts (better) or notches can be cut in the cross member to secure the posts (best). Below are sketches for all three methods. Notch cutting is most frequently seen in period photos.

A 2x6 brace is nailed from post to post. Single braces may be used for economy but a double brace on each side of the post is recommended.

Truss plates securing the post and top beam are used here. 2x4 blocking supports the beam before nailing and may be removed or left in place. Truss plates should be pre-drilled to eliminate the possibility of splitting the plate while nailing.

Notches cut into the top beam provides the best method for strength and longevity. Lag bolts or 6 inch nails are used to secure the beam to the post.

Cutting notches in the field can be done in a number of ways. Besides the standard method of cutting the notch out of the beam on all sides with a circularsaw, you may simply set the depth of the notch cut needed on your saw, make several cuts a half-inch apart and chop out the wood with a hatchet. Easy.

FIRESTEPS: As with revetments, there are many ways to build firesteps. They may be constructed independent of the revetment structure as a free-standing firestep, or they may be attached to the structure as shown in the examples below. The supporting members need to be sturdy enough to handle the weight and stress of soldiers stepping up onto them. Although 1-inch thick planking is frequently used for the firestep itself, 2-inch thick members are recommended for longevity, especially if support spans are greater than 2-feet. Two 1x planks can be nailed/laminated together to achieve this thickness. If single 1x boards are used they will generally need replacement within 4-6 years.

Height dimensions are not shown here since this needs to be adjusted accordingly to the height of your revetments and the average height of your unit members.

MISCELLANEOUS:

Firing shelves are useful to support the weight and facilitate use of the rifle, as well as contributing to lateral support for the revetment system.

They may be constructed of 1x planking or 2x members as shown. The exterior revetment facing of metal or wood can be attached to the fire shelf for additional support for both. Pre-drill all blocking to reduce splitting.

When placing sandbags at the parapet try to avoid any direct contact with the wood as the moisture retained in sandbags will rot the wood with constant contact.

Trench ladders are generally constructed out of sawmill 2x4s. The ladder width should be at least 24 inches and the spacing of the steps should be in the range of 14 inches apart for safety. The wood members should be secured together with 16d or 20d galvanized nails. The step boards should be pre-drilled to reduce splitting during nailing. Any boards that split during installation should be discarded.

Trench cover is occasionally added in some locations using sheets of corrugated metal to provide areas in the trench system that are protected from the weather and incoming grenades and that also offer some shade during the day. The metal sheets are simply fastened to the truss tops. Purlins of 1x material may be used as shown in the sketch so that the panels are laid perpendicular to the trench and will direct any water off the sides of the revetments rather than into the trenches. Purlin height may be adjusted to direct water flow to one side or the other.

It is recommended to paint trench cover metal panels in camouflage and scatter a few shovelfuls of site soil on top to help conceal it.

Part 3 – Underground Structure design & sample sketches

Building underground or partial underground structures may seem like a daunting task at first but it is really very little different than building a typical post and beam or timber-framed building above ground, with the addition of two needed modifications: 1) The walls that soil will cover need to be thoroughly waterproofed much like the roof and 2) Walls that soil will be placed against will need additional bracing to withstand the soil pressure. The force of this pressure over time can increase and fluctuate due to freeze-thaw at our site.

With the exception of these two considerations, the construction method is the same and is rather straightforward. Period photos of many underground bunkers show typical post and beam construction, a building method that has been around for hundreds of years.

With the help of modern tools and fasteners, this type of construction can be relatively easy to build in the field.

This section will help guide you through the progressive steps from site selection to building the bunker.

THE TWO MODIFICATIONS NEEDED FOR UNDERGROUND STRUCTURES

1. WATERPROOFING THE WALLS - The wood planking sidewalls of the structure need to be protected from the moisture of backfilled soil. Simply covering your walls with tarpaper, then backfilling will not work. Do NOT do this! Typically walls are covered with metal panels and frequently rubber membrane that is used for roofing is draped over the walls that are to be backfilled. The membrane is tightly sealed at the corners and carried down to the grade level. Even with this rubber membrane, condensation may occur if the rubber is installed flat against the wood walls. It is recommended to install the layer of metal paneling between the wood walls and the rubber. Since these metal panels will be hidden from view inside and out, the use of modern ribbed panels in lieu of the more-expensive corrugated variety can be used.

An alternative (better) method is to install some pressure-treated 2x4’s on the exterior of the wood walls (see following sketch) and attach the metal panels to these “studs”. This creates a small air space between the metal and wood walls, which will greatly help to keep walls dry and long lasting. The spacing of studs should be no greater than 2 feet apart or there will be some deformation in the metal panels from the weight of the backfilled soil.

TIP: Install tarpaper between the wood wall planking and the metal panels. Not only is this good practice to help reduce condensation but also when the wood planking shrinks, gaps will open up between the boards

(which is normal) and the panels would be visible through these cracks. The tarpaper will hide the panels and help seal the gaps.

2. LATERAL BRACING – Lateral bracing should be installed for walls that abut backfilled soil. The lateral bracing should run from top to bottom at corners that will be buried as shown below. These braces can be as small as a sawmill 2x4 fastened securely. Installation is relatively simple. Take care when in the planning stage not to locate doorways where this bracing will be needed. If your wall span is very long, additional bracing of this type may be needed in mid-section.

In a typical post and beam structure, knee braces are frequently used and attached diagonally between posts and upper beams, offering general stability to the structure. Knee braces however were originally intended primarily for wind resistance in above ground buildings. Buried structures generally need the additional lateral bracing at the corners to resist soil pressure in addition to this normal bracing. Otherwise when backfill is placed, the structure can lean in, rack and will not be plumb, even collapse in a worst case.

Example of 2x4 lateral bracing

LOCATION AND EXCAVATION: a few basic principles that should be followed:

1. LOCATION – Choose a location at the site with sloping ground so that the excavation will cut into an existing embankment of sufficient size and depth to accommodate the building, and so that the structure will be “buried” on three sides when completed. The depth of the excavation should equal the planned height of the structure if at all possible. If the structure is set too high above grade, soil will have to be built up against the sides and may erode away over time and could present a continuing maintenance problem. The lay of the land will dictate the final coverage for the structure. The sketch demonstrates the ideal situation.

2. EXCAVATION SIZE – The excavation for the structure should include and allow for an additional four feet working space around the three sides of the structure to be buried. For example, a 12 ft. wide x 16 ft. deep bunker would need a min. 20’ x 20’ excavation. This may seem excessive but the excavation sides quickly erode with every storm at the Newville site. If you shortchange this working space, you may pay dearly in labor for working in tight corners down the road.

German Gruppe shelters in the Vosges 1915

3. SPOILS – Make sure the excavator stockpiles the excavated material (spoils) in a location that will not block access to any trench lines or interfere with Newville events and can still be accessed easily when the structure is completed and the backfill is to be placed. Excess spoils/material that will eventually need to be hauled away or spread out on the site when the project is completed is another factor that should be taken into consideration.

LAYOUT AND GRADING

After excavation is completed the next step is to lay out the foundation footprint of the structure. Wood stakes, strong string (such as mason's line), a line level, tape measure and hammer are needed. Layout can be done with an instrument, by eyeballing with a carpenter’s square, or anything in-between. To achieve 90 degree corners, one old carpenter trick is to use the 3-4-5 rule.

Whether string line or lumber (as shown above) is used, the principle is the same: If you have a triangle with one 4-foot side, one 3-foot side and a hypotenuse (diagonal) of exactly 5 feet, then the angle opposite the hypotenuse will be exactly 90 degrees.

For a simple string line procedure: first, drive a corner stake into the ground at a desired corner. Attach two string lines to the top of the stake. Tie the far end of each line to the top of adjacent corner stakes. The length of each line should be the desired length of the foundation footprint on two sides. Drive one of the stakes into the ground along the basic footprint and mark the string at 3’ from the corner stake. Drive the other stake lightly and mark it at 4’ from the corner stake. Place a tape measure as shown at the 3’ mark and then move the second stake until the tape measures exactly 5’ from the 3’ mark to the 4’ mark. Make sure the 3’-4’-5’ measurements are precise. Drive in the second stake. Continue with the same procedure for the remaining corners.

TIP: After completion, measure the distance across the diagonal from one stake to the other as shown in this sketch, as a check. The two measurements should be the same. If not, one of the stakes may be off so make adjustments accordingly.

Then place a line level on the string lines between stakes, adjusting the lines up or down on the stake until level is reached and mark the point on each stake accordingly. It is not necessary to have the grade perfectly level. However, it is necessary to have the bottom elevation of the footings/foundation level; all foundation points need to be at the same elevation. Measure down from this mark on all the stakes.

The excavator may have left the excavated area relatively level but generally some fine-tuning is needed here and there. In some places the foundation may need to be raised with fill, masonry or gravel. In other instances it may need to be lowered by hand grading. If the structure's grade is off by even a few inches for example, it may be more difficult to obtain level floors, square corners and the correct roof pitch.

NOTE: In the following sections foundations and framing are covered separately. They frequently go hand in hand however, since in most cases the bottoms of posts (part of the framing system) are integral to the foundations. There will naturally be some overlap in these sections.

FOUNDATIONS:

The most important component of the underground structure is the foundation. Do not shortchange the design here. This is generally true for all buildings but even more so for underground structures. Once the structure is buried it will be difficult, even impossible, to go back and make repairs to the foundation if there are problems and deficiencies there.

Pressure-treated lumber must be used for the foundation. Sawmill lumber will quickly rot and decay with ground contact, especially for a buried structure where moisture cannot quickly evaporate. In the interest of authenticity, the pressure treated lumber is concealed later in the construction.

Foundations can be constructed in a number of ways but the conventional joist system is the most commonly used and will be shown in the examples here. The foundation lumber should be pressure treated and generally 2x’s are utilized. Some masonry items such as block or stone paving squares are frequently used for foundations to separate wood from ground. An example of a foundation plan for a 12’ x 16’ structure is shown here:

In the joist system an outer frame is constructed around the perimeter. This frame may be referred to as headers, rim joists, sill walls, etc.. but will be called header boards here. Joists between the header boards run across the shorter dimension of the two spans. The size of the pressure treated headers and joists should be matched with the size of the structure and the length of the span.

This typical span table for pressure-treated lumber (Southern pine) shows maximum span lengths for each size of joist. For example, 2x6 joists spaced 12 inches apart should not exceed a length of 10’4” for No.1 prime lumber.

2x6 joists and header boards may be adequate for smaller structures and spans, but 2x8 to 2x12 sizes are recommended when the length of the span increases.

For 1-inch thick rough sawn floorboards, it is recommended to space joists at 16 or 24 inches apart. For 2-inch thick floorboards, they may be spaced 24, 32 or even 48 inches apart when the load is static.

Joists should be attached to the header boards using metal joist hangers, which will keep the floor strong as the wood dries, shrinks, twists and ages. Use common nails to attach the joist hangers. Do not use roofing nails or screws as both lack the shear strength needed for joist hangers.

Alternately, the joists can be attached by simply nailing through the header walls in lieu of metal hangers but this requires careful nailing and perhaps some pre-drilling of pilot holes or the attachment may not prove to be as strong in the long run.

Even pressure treated lumber will degrade over time in direct ground contact, especially in situations where ground water may collect and pool, so extra care should be taken to support the foundation frame off the ground.

Foundation framing, especially in the joist system, can be kept above ground by the use of spacers such as bricks, masonry or stone pavers as shown here. Solid masonry blocks, stone dust, even large flat stones can also be used.

TIP: The bottom of sawmill posts (end grain) that will contact the masonry spacers should be treated with a wood preservative or bituminous coating. The end grain of sawmill lumber is the most susceptible point for moisture entering and rot resulting so it is recommended to treat the bottom of all structure post ends accordingly. These products are readily available from home centers and can be applied by brush or by soaking post ends in a container.

All load-bearing posts in the structure need to be supported down to the foundation and not on the finished floor.

TIP: Cut all joists to exact same length even though you may need to draw the header boards in or force them out a little to make fit. If the joists are cut to different lengths to meet the conditions, the devil to pay will come due when the floor planks are installed later.

Here is a sketch where large 6x6 pressure-treated lumber is used for the perimeter walls. The posts are placed directly on the perimeter timber in this example and can be fastened using large lag screws installed diagonally at the post bottoms into the member below. Pre-drill and countersink lag screws and install on multiple sides of post in this application.

12 X 16 STRUCTURE: The 12’x16’ structure as previously shown yields 192 square feet which would be suitable for a barracks for up to 8+ men (depending upon bunk arrangement), a command bunker, aid station, etc.

Larger structures may need larger dimension wood members but the construction system and procedure to be followed is generally the same.

In this example the 2x8 joists are placed at 16 inches on center, designed for 1-inch thick floor planking. The joist spacing may be greatly increased if 2-inch thick planking is used.

The joists are 12-foot lengths. Mid-span joist support is not needed here if 2x8’s are used.

The 4x6/4x4 posts are set at 4-foot centers on the three sides that are to be buried in this example.

At the front wall (the unburied side) posts are optional when conventional stud wall framing is used. This will be covered later in the wall section.

The structure’s posts are usually installed at the same time as the foundation grid.

20 x 20 STRUCTURE: Following is a typical foundation plan for a 20-foot x 20-foot structure. This 400 SF structure is the maximum size currently allowed by the GWA for structures within the battlefield (inside the back road). This size structure could accommodate up to 18 men, depending upon bunk arrangement.

In this example, 6x6 posts are used and center posts are added. Mid-section header boards are attached to the center posts with lag screws to which the joists are then attached.

It may be desirable to have just one post in the center of the room instead of 3 as shown. This requires using larger wood members in the roof framing to accommodate the increase in span length and may need equipment to help set these heavy timbers. Consult with the Trench Master for design.

A single header board may be used in the center instead of the pair as shown in the previous sketch but joists of different lengths will then be required for each side. When attaching joists on both sides of a single header board, stagger joist placement as shown. This applies whether nailing (as shown) is used or joist hangers are used.

Blocking using short lengths of the 2x lumber may be installed between joists to prevent twisting of the joists. This is particularly useful for long joist spans and gives extra stability to the flooring above.

It is recommended to place additional support in the joist system where heavy loads such as wood stoves may be placed above.

Example of a joist foundation at the site

FRAMING:

After the foundation has been completed, the structure’s frame is constructed. Vertical posts are often installed at the same time as the foundation phase as previously described. It is important to select wood members for the framing that are of sufficient size and strength to withstand the stress of being buried and the long term soil pressure, concerns not needed for a conventional above-ground structure. 4x6 or 6x6 posts are recommended over 4x4 or smaller posts for corners, for example.

Adequate framing for the roof is essential for underground structures in order to support the loading that will occur. Besides the weight of the roofing materials and several inches of soil that may be added on top, consideration must be given to snow loading over the winter at the Newville site. Several inches of snow will add considerable weight, sometimes measured by the ton, to the roof structure. Short-changing the roof structure and the posts’ ability to support it could result in disastrous consequences.

Pay attention not only to the size of wood members that will support the roof but also to the span the members have to cover. When long spans are needed for larger structures, they will need the additional support of center posts, as previously mentioned in the foundation section. While these may intrude on floor space, these center posts are unavoidable in larger structures unless substantial beams or girders are used.

There are many tables available online that show spacing and maximum span lengths per species of wood used. They can be very intimidating, even confusing. Suffice to say, better to overbuild and over design than take a chance on an insufficient design. If there are any doubts or questions, the Trench Masters can be consulted and may be helpful during the design phase of construction.

TIMBER FRAMING / POST AND BEAM: In the truest sense a “timber framed” structure is one that is held together with wood pegs or wedges, a construction method that dates back to medieval times. “Post and beam” construction often resembles timber framing, with the important distinction that post and beam construction utilizes mechanical fasteners and often steel plate connectors to join adjacent members together. In this guide the two terms are used interchangeably.

This method of construction differs from stud wall or “stick built” framing which is often used for above ground structures and homes, but may not be strong enough for buried structures.

In post and beam construction there are as many plans as there are buildings. There is no “one way” to build a timber-framed structure.

As discussed in the foundation section, posts can be stood up and fastened to the foundation. Connecting top members are then fastened at the top of the posts around the perimeter. Roof support beams are added later.

Traditional timber framing designs make use of “bents”, an assembly of timber components that can be put together flat and then stood up into position. Bents are usually cross frames, but may also be longitudinal wall frames. Bents include the main roof support beams. The drawback to bents is that they are usually very heavy and a large crew is required to lift them.

All posts need to be made plumb before additional framing is added. Use the four-foot level for this and then secure the posts with temporary braces. This applies to both single posts and bent type assemblies. This temporary bracing can be accomplished with diagonal 2x4’s secured to the foundation frame or to stakes as shown.

After posts are plumb, attach some lateral 2x4 temporary bracing between posts or bents. These 2x4’s can be used later in the structure for studwork or miscellaneous framing so there is no waste. Don’t drive nails flush on bracing, for easy removal later.

HEIGHT: The height of the posts at one end of the structure (usually the end opposite the door) should be greater so that the roof will have some slope. A totally flat roof will collect water and must be avoided. Any soil covering will retain moisture on the roof that needs to drain off. A fall of at least 2 inches for every 4 linear feet is recommended.

Measure and cut the height of posts before installation. Use the Speed Square to cut the correct angle at the top of the post.

The next step is to tie the posts or bents together around the perimeter. This is usually done at the top of the structure framing. This can be accomplished in a number of ways, depending on the method of construction and materials that are used. Some examples are shown here.

In this example, 6x6 or 4x6 beams are set with a 4-inch bearing on posts, and attached using long countersunk lag screws and washers.

A continuous 2x6 is attached, bearing on posts and fastened to beams with shorter lag screws and washers.

Drill pilot holes for lags. Align so that vertical and horizontal fasteners do not meet.

Lag screws can be attached using a socket set, a heavy-duty drill or an electric impact wrench. The latter will make the job easier.

A variation on the above example, particularly useful when smaller posts are used, is shown to the right. A 1-inch notch is cut in the 4x6 beam and the beam is installed with full bearing on the 4x6 post. Countersunk lag screws are installed as above.

A continuous member is nailed flush to the posts and the end of beams. In the example here, the 1x8 top board of the wall planking is used. Several courses of these boards may be added if more stability to the frame is needed.

In this example, a pair of 2x6s is fastened to both sides of the posts using carriage bolts.

The bolts run through both 2x6s and the post and are fastened with nuts and washers on the interior side. Pre-drilling is needed.

A 2x6 header board is attached to structure ends as shown.

2x6s as shown may be used for short spans. Substitute 2x8s if longer spans are needed.

This example shows same-sized beams such as 6x6 or 4x6 used continuously around the perimeter. A 45-degree angle cut can be made where beams join at corners. Two predrilled lag screws are used to connect the beams here.

The lag screws need to have more than half their length in the embedded beam. Use 7-8” long bolts for 6x6 and 5” long bolts for 4x6, for example.

Below is a method to connect beams together other than at corners. The beams are notched to fit together (a reciprocating saw is useful for this) and connected with predrilled lag screws. Connections need to be at post locations. The connected beam is then toe nailed onto the post on both sides with 20d nails. In the sketch 6x6 beams are shown but other sizes can be notched in a similar manner.

When bents are used, a top course of wall planking around the perimeter exterior and 1 or 2 roof planks on both sides of the structure can be used to tie the framing together as shown below. Do not install additional roof planking at this time or the structure may become “top heavy.” Additional wall stabilization will be needed first.

If a conventional joist system is planned for the roof framing as shown here, the header boards – in this case 2x8 – can be placed on top of the support posts and fastened to the posts with heavy duty metal clip angles or straps. The rafters are installed later.

After the perimeter framing is complete and all posts are secured top and bottom, install the lateral bracing (previously covered in the “Two modifications needed for underground structures”) and any knee bracing.

Roof framing is then installed. This frequently involves some heavy wood members to be set in place overhead and having a good crew size for installation is generally necessary. Roof supports are lifted into place and fastened while held secure and several hands are needed for this. A few examples of roof framing are shown below in section views.

If smaller rafter spans of 8-feet or less are used, 2x6s may be used for rafters. The thickness of roof planking installed on them will depend on the spacing of the rafters. And the closer the rafters are to each other, the stronger the roof will be.

When bents are used, they may be spaced at longer distances on center when heavier (thicker) planking is used.

The strength of wood members used to support the final layer of planking/tin is derived primarily from the width (in this case height) of the wood parallel to the grain. Avoid the temptation to cut down on rafter size to keep overall bunker height down. No strength will be achieved by using smaller members in greater quantities for example.

If a corrugated metal panel ceiling is desired, a wood “lattice” of boards can be used for support and spacing since panel connection points generally need 24 inch spacing in both directions. See the corrugated metal ceiling framing plan for the 12x16 sample structure below for this installation procedure.

The following sketches show sequence of framing for the 12x16 structure and the 20x20 structure examples.

FRAMING PLAN FOR THE 12x16 STRUCTURE (for wood ceiling)

FRAMING PLAN FOR THE 12x16 STRUCTURE (for corrugated metal ceiling)

In this method, a lattice of 2x8s and 1x8s is created and the corrugated panels are attached to the 1x8s using 1-inch sheet metal-to-wood sealing screws. The corrugations in the panels run to the 12’ side of the structure.

FRAMING PLAN FOR THE 20x20 SAMPLE STRUCTURE

4x6 beams in 10 ft. lengths serve as the primary support in this construction with 2x6s securing the perimeter and center posts together. 2-inch planking is required in order to span the 5 ft. between beams.

If a corrugated metal panel ceiling is preferred, then a lattice of 2x8s and 1x8s is constructed in the same manner as for the 12x16 structure shown previously, in lieu of the 2x8 planking.

2x6s are connected to 4x6 beams using metal framing L-angle clips as shown. The ends of the 2x6s rest on the posts below. At the center posts, use angles on both sides of the 2x6. Use common nails, not screws, to attach the metal connectors.

Simpson Strong-Tie makes a variety of galvanized metal connectors for timber and their products are available in the lumber department of retail outlets. Metal connectors are easy to use and make for safe connections. Use 12 gauge or heavier thickness. They may be painted to help conceal the modern look. This method of construction offers a simple solution for the average DIY builder. More advanced timber-connecting techniques such as notching timbers, using through-bolts and lag screws, and the like may also be used but are not shown here for this structure in the interest of simplicity. See alternate below.

One alternate method of fastening which does not use the Strong-Tie connectors is shown here. The beams are notched to fit the posts and galvanized lag screws with washers are used. Lag screws through the beam are countersunk to allow 4-inch penetration into the post. Two lag screws are used at each location and placed diagonally. Similarly, the 2x6’s are installed flush to the beam with lag screws This will result in some loss of headroom in the structure but makes for an easy connecting system that avoids modern Strong-Tie fasteners.

ROOF OVERHANGS AND PORCHES

To construct an overhang for the door/open side of the bunker, extend the roof beams out several feet beyond the wall (use 12’ or 14’ long beams vs. 10’ beams for this purpose in the 20x20 structure, for example.)

It is not recommended to extend the structure’s roof for more than 2-3 feet for this purpose without additional support such as posts at the extended ends.

Fasten boards to support the metal panels along the length of the extended beams as shown. Board spacing should not be greater than 24”.

In this sketch, 2x8s are shown in order to align with the roof framing. A fascia board can be also added as shown and may offer additional rain protection.

When the structure’s wall planking is added, the top boards are cut to fit flush around the extended beams.

If the roof framing beams run in the opposite direction, support for the overhang can be added such as in the example shown here.

2x4 support braces are attached to a continuous 2x4 header board at the top, which is firmly attached to the structure. Angles are cut with the Speed Square. The spacing of braces from one to another should be 24”, which is the standard width of corrugated panels with overlap. If greater spans are needed, such as over doors, wood planks span the gap.

Metal panel sections are cut to fit, attached to the braces and tucked under the main roof panels

A simple door or window overhang can be constructed from project scraps and attached to the structure. Use caulk or bituminous coating to seal any gap at the rear of the metal panels.

If a porch for the structure is desired, a basic example is shown below. A porch can be constructed at a later date from the main project since it is basically a freestanding structure that is attached to the bunker.

The 2x6 header board is attached securely to the front of the structure with lag screws and washers.

Porch posts are 6-8 inch locust logs for a rustic authentic look in this example. Secure bottom of posts in ground and make plumb. Post to post spacing is 6 feet.

6x6 posts may be used in lieu of logs. Use masonry supports and treat bottom of posts when sawmill lumber is used.

Paint metal roofing panels in camouflage. A small amount of soil and foliage may be added on top for further camouflage.

After the framing of the structure is completed, there are two choices at this point in the construction: some builders prefer to install the flooring first to provide for a stable platform to work on and to avoid having to constantly step (and trip) over the floor joist system; others prefer completing the roof structure first to gain weather tightness before the flooring is installed, especially if there may be long lapses between work trips. This is builder’s preference depending on the circumstances.

FLOORING:

The installation of flooring is rather straightforward and will not be discussed in great detail here except for the following key points.

8-inch (or wider) width planking for floors is recommended. Whatever cost savings may be had for smaller widths, say 4 or 6-inch, it will quickly vanish with the extra labor required to install them. The larger the board width is, the better. Not only does it reduce installation labor but it adds to the long-term durability.

The thickness of the rough sawn floorboards used will depend on the spacing of floor joists below. One inch thick planking may be used if the joists are spaced 16 to 24 inches apart. One-inch planks may be susceptible to sagging (and eventual cracking and replacement) if this proper support is not provided.

Two-inch thick boards will increase the span needed between joists to 32 to 48 inches, another laborsaving consideration since joists are frequently more difficult and time consuming to install than floor planks. Note that the 16, 24, 32 or 48-inch spacing for joists are measures that work ideally with 8-foot long planks, the most frequently used length.

Floorboards should be staggered so that the ends of planks do not all line up at the same location, which may stress the joist below.

At post locations, blocking may be needed to support the end of floorboards if joists are not present. Blocking can be cut from 2x4 stock and attached to the post as shown in the sketch. Small blocking should be predrilled to avoid splitting during installation. Blocking may be needed at other locations where the edge of floor planking needs support and can be cut from excess joist lumber and added between joists as shown in the photo.

Cut nails are frequently used to install flooring for a more “authentic” look. They are slightly more expensive than traditional nails. Cut on all sides to produce 4 edges, they are often called “square nails.” The characteristic square head looks distinctive on a wood floor. Be forewarned however: if future floorboard replacement is needed or if any mistakes are made during installation, it is nearly impossible to remove a board fastened with cut nails without destroying the wood planking.

The ends of rough-sawn boards often contain checks (cracks). Some checks are obvious, but some won’t be discovered until the board is cut near the end. So plan on discarding several inches on each end of every board. Sawmill boards frequently come several inches longer than the ordered length.

When nailing very close to the ends of floorboards during installation, some splitting of the wood may occur. If this happens, drill a small pilot hole for remaining nail locations.

TIP: Check the end grain of each floorboard and install as shown below to prevent any future warping and possible toe-catchers. This is especially true for one-inch thick floorboards that may still be green when installed.

An example of rough sawn 1-inch plank flooring

ROOFING:

The material used for the roof largely depends on the “look” that is desirable within the structure (i.e. when one looks up at the ceiling). If metal is preferred, the panels should be of the rounded corrugated type for authenticity purposes. The panels are fastened directly to the wood support system. If a wood ceiling is preferred, then wood planking may be installed on the support system in a similar manner as the flooring and then modern metal ribbed panels may be installed on top of the planking. Surprisingly, the material cost is about the same. The square foot cost between wood planking and modern metal panels vs. the more expensive corrugated metal panels is roughly equal; only the amount of installation labor differs. Often this is negligible due to the increase of difficulty in installing corrugated panels correctly. Additional rafter joists are also needed for the corrugated panels.

In both instances fasten the metal panels with sheet metal-to-wood sealing screws. These specialty screws have rubber washers that seal against moisture and are readily available from suppliers. A socket drive head for the drill is useful for installation of these screws.

Adjacent corrugated metal panels should be overlapped at the ends as shown on left with a minimum 6 to 8 inch overlap recommended. A minimum lap and half overlap between panels is also recommended. Half-laps and single laps frequently leak.

If modern metal panels are used and installed on top of the wood planking, the panel end overlaps are similar but the sides of the panels only need a single lap.

Rubber membrane roofing material, which is available in large sheets, is placed over the metal panels. The membrane provides the extra layer of moisture protection needed for underground structures. Occasionally this process is reversed with the rubber membrane placed over the wood structure and then the metal

panels are placed on top. In both instances, care should be taken to insure the integrity of the rubber membrane. Penetrations should be sealed thoroughly.

Any seams in the membrane must be secured with a special adhesive but the installation of rubber roofing material is rather straightforward. The membrane is simply draped on and over the edges of the roof.

An example of rubber membrane roofing

A thin layer of site soil usually up to three inches in depth is then placed over the rubber membrane on the roof for camouflage. When the structure is backfilled, the backfill soil is brought up to the roofline to meet the material on the roof and thus the structure will gain the appearance from above of being completely buried.

The structure walls can also be covered with this rubber membrane material for additional moisture protection but the structure’s wall construction, covered in the next section, should be completed first. In this use, the membrane is draped over the roof edge and continues down the sides to grade level.

TIP: Paint the rubber membrane, or metal panels if applicable, on the roof surface with a flat khaki color (similar to the site soil color) before the soil is placed so that even a very thin layer of soil covering will effect the camouflage.

WALLS:

In the main, wood planking is used for the wall material. Rough-sawn 1-inch thick boards are frequently used, and attached to the exterior side of the framing and this will be the default here.

Corrugated metal panels could be used for the walls but may contribute to dampness within a structure, so that should be a consideration. Wood planking could be installed on the interior side of the framing, but considerable space would be wasted. It is not necessary to use 2-inch thick boards for the walls although there is nothing wrong with building a Fort Knox if the post and stud framing is solid.

Wood studs generally need to be installed between the structure’s posts. The distance between posts can be greater than the recommended spacing needed to support the wall planking, so studs between posts are usually needed. This is done after the flooring is completed.

Rough sawn 2x4’s are used for the studs. The wall planking (and any metal panels attached to them) will be supported by a combination of these studs and the posts. The spacing between studs/posts should be 16 to 24 inches on center.

Example of stud wall construction

Studs can be fastened directly, toenailed to the floorboards and wood beam on top, but stronger support will be gained if a top and bottom 2x4 plate is used as shown in the above sketch. Also with this type of assembly, stud sections may be measured and fabricated on the floor then fastened into place.

The wood planking will be installed horizontally around most, if not all, perimeter walls and so studs are placed vertically. If the wood planking is installed vertically such as board-and-batten construction for the “front” or exposed portion of the building, the studs would be placed horizontally.

Horizontal wall planking is installed from the bottom up and nailed securely to the studs and posts. Planking should be checked with the level as courses go up to insure the walls don’t “walk” up at one end or the other during installation. As with floorboards, 8-inch (or larger) width boards are recommended.

Install the wall planks with three nails at every stud/post location. 8-10d galvanized common nails are recommended for 1-inch planking. At the structure’s corners, overlap ends of boards as shown in the plan view below.

Tarpaper (asphalt impregnated felt) should then be installed on the exterior side of planking on the sides to be backfilled, starting at the bottom with each succeeding layer overlapping the lower layer. Tarpaper may be fastened with staples or with roofing nails. Mark the tarpaper with chalk or carpenter’s pencil as you go up to show the centerline of post and stud locations. This will facilitate the nailing of metal panels later.

Finally, metal panels are installed on the exterior face of all sides to be backfilled. This is discussed in the beginning of Part 3 under “The two modifications needed for underground structures.” The panels are attached using the metal-to-wood sealing screws mentioned in the roofing section.

The front or exterior face of the structure that will be exposed requires no felt or metal panels of course. It is generally constructed with horizontal planking or vertical planking (board and batten). Horizontal planking is perhaps the easiest to install but the butt joints between boards are not rain proof so some roof overhang is recommended in this case.

Note that if the rough sawn planking is green, there will be shrinkage of the boards and gaps between the boards may occur. Any green wood from the sawmill will take several months to thoroughly dry.

When board and batten construction is used, install the vertical planking first, then install the battens and nail on one side of the battens only. Later after shrinkage of the boards has occurred, the other side of the batten can be fastened. This will prevent twisting of the battens, nail pull outs and battens not fitting snugly to the boards.

Shiplap or clapboard construction (overlapping boards) can be is used for the exposed front of the building in lieu of vertical or horizontal planking. This type of construction will provide more rain resistance at the front wall vs. flush planks, especially if there is minimal roof overhang. The drawbacks are that shiplap siding is slightly more difficult to install and may allow some small air gaps to occur with shrinkage. However, this may be beneficial for the overall ventilation of the structure over time.

Wood planking is usually left unfinished. Raw wood on the front exterior face exposed to the elements may benefit in the long term from a coat of oil-based wood preservative.

DOORS & WINDOWS:

Door and any windows should be framed before wall planking is installed. 2x4 framing is used for these openings. Care must be taken to insure this framing is precise and plumb to prevent doors and windows from binding. Doors and windows are often the last items to be completed, to allow as much shrinkage of the sawmill lumber as possible to occur before installation.

Double studs are recommended for doorjambs and door headers, especially if the door is heavy or subject to heavy traffic.

Alternately, 4x4s can be used in lieu of double 2x4 studs.

Use wood shims on all sides of the door to set it evenly in the opening, and then install hinges. The door should swing freely and not bind at any point.

All doors should swing out from the inside of structures. This is a safety requirement.

Doors can be old salvaged doors or can be built from scratch. A simple door fashioned from 1x8 boards is shown here.

Use vintage hardware or exterior black Iron Gate hardware for doors if possible.

Windows are frequently added to the exposed wall of underground structures to add daylight; the interior can be dark if only lit by an open door.

Whitewashing the interior planking is another option to add more light inside the structure.

Vintage window frames & glass can be frequently found online and in building recycle outlets. Plain wooden windows can be obtained from some suppliers.

Windows are framed in the same manner as doors. Double studs are not required.

Window shutters are an option to consider.

CAULKING & SEALING:

Caulking is usually not needed in the interior of the structure (except for the frequently futile attempt at “mouse proofing” and the like). It is however an important consideration for the exterior face of the structure. Seams and corners on the exterior side should be sealed for protection against migrating moisture, especially where backfill occurs.

Corners where metal panels meet should have metal flashing installed around the corner; otherwise the rough ends of the metal sheet may tear the rubber when it is placed. The weight of placed backfill occasionally compromises building corners that are not protected. Expanding foam sealants are also often useful for sealing seams and gaps in the exterior metal panels before backfill is placed.

Metal flashing Expanding foam sealants

BACKFILL:

After the structure has been completed, backfill is then placed around the back and sides of the building. This should be placed in two or more “lifts” in sequence around the structure to prevent undue loading on any one side of the structure during the backfill procedure. Sandbags may be used on the structure sides to hold soil back where the backfill ends.

An underground drainage system around the perimeter may be helpful if the surrounding terrain slopes towards the structure and rainwater may become an issue. Use perforated drainage pipe, readily available from retail suppliers, and install at the grade level before the backfill is placed. Make sure that the piping slopes consistently from high point to low and toward the outlet end(s), which should lead away from the structure. Exposed ends of this piping can be concealed using sandbags and the like.

FURNISHINGS:

Interior furnishings such as bunks, gun rack, shelving and the like are left up to the individual unit’s needs and design, and will not be discussed in any detail here. However, there are a few suggestions and tips worth mentioning:

Lanterns should be hung on lantern brackets that will keep them a safe distance from combustible wood members. Large nails should not be used to hang lanterns.

For rope bunks, use min.1/2 inch diameter sisal rope, not modern rope. Drill 5/8-inch diameter holes at bunk sides for the rope. Five to six inches is a good spacing between ropes for the lattice. Note that over 100 feet of rope is needed for a nominal 4’ x 7’ bunk.

The lowest bunk platform can be extended out eight inches or more to provide a bench for sitting as well as a step to the upper bunk.

Seating arrangements inside a bunker can often lead to cramped quarters. Utilizing a bunk bench such as this or using folding chairs and tables can often economize space.

Consider using wood pegs or metal hooks in lieu of nails for hanging uniforms and gear in the bunker. Nails may tear clothing and leather. If nails are used, avoid modern nails in favor of cut nails or forged nails. 1-inch wood dowels cut to length make good pegs.

RIFLE RACK: A basic design for a rifle rack suitable for the Gew98 (and other rifles) is shown here. You will need one 1x4 8-foot long, one 2x4 24 inches long, wood screws for assembly, and wall mounting hardware.

Use a 2-inch hole saw bit to cut the rifle rest slots. The slots are placed at 3-inch centers and are 2 inches wide and 1½ inch deep.

MASONRY

Masonry work is beyond the scope of this design guide except for a few basic principles and some general procedures. This is specialty work and won’t be covered in much detail here. Experienced individuals generally perform masonry work at the site.

There have been several masonry structures erected at the site in recent times. Groups who took the extra time and had the skills to make the structures look very authentic for a war torn area have built some very nice structures such as the Allied 117th Sanitary Train’s bunker shown here.

Here are a few basic principles for masonry construction:

1. Brick or block walls require a concrete footing. The footing needs to be continuous and under all walls. Footing size may vary but a good rule of thumb for our purposes is 16-inches wide x 6 to 8 inches deep for a low height wall.

Rebar is necessary to keep the cured concrete from cracking over time. Rebar can be supported on bricks in the footing trench when the concrete is being poured. Vertical rebar is needed at intervals to secure the wall to the footing.

2. All block structures at the site need to be parged so that the modern block finish is concealed by a smooth or stucco looking finish. A parge coat consists of a thick sand and cement mix that is troweled onto

the block. A typical parge mix is 3 parts sand to 1 part Portland cement, or packaged sand mixes can be obtained at home centers in 60 to 80 lb. bags. One 60 lb. bag will cover approximately 200-250 square feet of block surface. The block must be kept damp before the parge coat is applied to insure adhesion. In hot weather, the parge coat should be misted to keep it damp. Cracks may occur if it dries out too quickly. When cured, the parge coat can be painted or left unfinished.

3. Block is a porous material and some moisture over time can migrate from the exterior to the interior. It is recommended to coat the interior with a foundation waterproofing seal. Some year-round ventilation through the structure may also help mitigate any moisture problems.

Part 4 – Barbed Wire & Sample Sketches

The use of barbed wire at the Newville site adds a realistic dimension to the battlefield but also requires an additional alert for safety. Here are some general tips for barbed wire use:

Always use leather gloves and long sleeved shirts when working with wire.

Eye protection is also recommended.

Always work with a partner when wiring. When cutting long coils of wire, always have one person on each end of the wire to keep it from springing under tension.

Use long handled cutters for cutting wire the wire and linesman pliers for bending and making repairs.

Use one-inch or larger galvanized wire fence staples when attaching wire to wood. Smaller staples will pull out too quickly over time.

Discarded wire should not be left on the battlefield or in the trenches. See site caretaker for disposal.

Never throw discarded wire into a shell hole. This is an extreme safety hazard, especially when shell holes are used at night.

Here are some photos and wiring diagrams taken from period military manuals. It is often not necessary to replicate the amount of wiring shown. Sometimes less is more and will achieve the same purpose for our representations at the site.

FIXED WIRING

For fixed wiring barbed wire is fastened to wood posts that are set into the ground.

To achieve this effect, use 3 to 4-inch diameter wood posts such as Locust. 6-foot lengths are a good size.

Using a posthole digger, embed posts 12 to 18 inches into the ground approx. 6 to 8 feet apart.

String wire from post to post and hammer with fencing staples. Wire may also be wrapped around posts and fastened.

A pair of lineman’s pliers is especially useful for this installation.

Heavy linesman pliers can be used to repair and splice wire that has been cut. This tool makes bending a loop at the wire end very easy.

PIGTAILS

Wire is strung between iron pigtails that are driven into the ground.

Anchor pigtails securely. Using a maul hammer on the lower rungs or driving a rebar stake for a pilot hole in the ground can help accomplish this.

Pigtails that are loose or not driven deeply will collapse in time.

CHEVAL-DE-FRISE (aka Knife Rests, Spanish Riders)

The cheval de frise (plural: chevaux de frise) has been around since medieval times and consists of a portable frame covered with wire. Also called a “knife rest” or “Spanish rider” during World War I, the device can be moved about wherever an obstacle is needed and can also be removed from the battlefield proper after an event to allow mowing.

Both steel angle frames and wood frames are used at the site. The following is a diagram from Stellungsbau, the German trench manual.

Wood frames can be constructed from 2x4s. 8 foot is a good length for the frame. Larger frames may be difficult for 2 men to move. Following are some basic instructions for constructing a wood frame in the field.

Give the wood frame a coat of paint or oil-based wood preservative to add longevity. When the finish is dry…wire away! Use wire fence staples of minimum 1-inch size to fasten wire to frame.

Very basic wiring patterns are shown in the above and below diagrams

Part 5 – Wood stoves & GWA fire safety requirementsOnly experienced individuals should install wood burning stoves in structures at the site. Older stoves such as period stoves often require careful attention to details to install safely. Stovepipe joints need to be secure, clearances from any combustible material need to be made, and flues need to exit gases and embers safely. From the GWA Site Regulations: Fireproof materials such as corrugated tin (metal panels) should be placed between the stove and any wooden walls or beams. All stove piping, which passes through wooden walls or ceilings, shall be of double wall flue type where the pipe passes through the wall. Stovepipes are discouraged from exiting into the trench system.

From National Fire Protection Association (NFPA) info on the web: All operating wood stoves and furnaces require specific minimum distances or clearance between the bottom, top, sides, front and back of the stove and all combustible materials. Insufficient clearance could cause heat produced by the stove to penetrate nearby combustibles, causing a serious fire.

Some examples of stove clearances

NFPA standards call for a 36-inch clearance between a wood stove and any combustible wall or ceiling surface. Installation clearances may be reduced from 36 inches by installing a heat shield such as sheet metal, spaced at least one inch from the wall along the combustible surface.The stove itself should be placed on non-combustible materials.

For our purposes, non-combustible materials such as bricks, stone pavers or a UL-approved stove mat should be used. A sheet of tin should be placed below any bricks/stone to prevent hot embers from falling between the cracks of bricks for example and igniting wood floors. The floor protection should extend 18 inches out from the firebox door.

Venting the stove is the most important part of the wood-burning system. 90% of all stove-related fires originate within the venting system. A venting system in our case consists of lengths of 24-gauge or heavier stovepipe. The vent should be as short as possible, with no more than 2 right angle elbows. The sections of stovepipe should be assembled with crimped, male ends of the sections facing down, towards the stove.

Stovepipe sections should be fastened with 3 sheet-metal screws or other fasteners at each joint. A manually operated damper can be installed in the stovepipe and is most effective when placed within 18 inches of the stove outlet.

Stovepipe clearance is extremely important. Unprotected walls and ceilings need at least 18 inches of clearance from the stovepipe. As above, heat shields will lower this dimension. Stovepipe must never pass directly through a wooden interior wall, floor, or ceiling without protection. Most fires start here. Use a metal double flue wall thimble for example or a roof thimble designed for this purpose.

Brace stovepipe on exterior side with metal brackets or straps using same clearances from combustible materials. The stovepipe needs to extend above the roofline. It is recommended to install a flue cap with metal screen to prevent sparks from possibly igniting nearby materials.

Install an operating smoke detector and a multi-purpose fire extinguisher in the same room as the wood stove. This is a GWA requirement.

Part 6 – Subcontractors and Suppliers for the Newville Site

SAWMILL LUMBER SUPPLIERS

Chestnut Road Lumber and Dry KilnSteve Hostetler, owner90 Chestnut RoadNewburg, PA 17240(717) 423-5941

Martin Lehman Lumber 41 Shagbark Lane Carlisle, PA 17015(717) 243-0690

Steve Wiser516 Middle RoadNewville, PACell: (717) 856-4946 Home: (717) 776-4764conoex516@gmail.com

Chad Bear223 Pine RdMt. Holly Springs, PA 17065Phone: (717) 486-7431 bearsilverfox@comcast.com

LUMBER AND HARDWARE SUPPLIERS

Lowes850 E High StCarlisle, PA 17013(717) 258-7700(Lowes also has stores in Chambersbug PA and Mechanicsburg PA)

Home Depot1013 S Hanover StCarlisle, PA 17013(717) 249-1771(Home Depot also has store in Mechanicsburg PA)

METAL PANELS, ROOFING AND HARDWARE SUPPLIERS

A. B. Martin Roofing Supply35 Ridge Road

Newville, PA 17241(717) 776-5951

RUBBER ROOFING SUPPLIER

Steve Wiser516 Middle RoadNewville, PACell: (717) 856-4946 Home: (717) 776-4764conoex516@gmail.com

HARDWARE STORES

Lantz Hardware9331 Newburg RdNewburg, PA 17240(717) 423-6681

True Value35 W King StShippensburg, PA 17257(717) 532-6511

EXCAVATION, DOZING

Steve Wiser516 Middle RoadNewville, PACell: (717) 856-4946 Home: (717) 776-4764conoex516@gmail.com

Chad Bear223 Pine RdMt. Holly Springs, PA 17065 Cell: (717) 226-2766 Phone: (717) 486-7431 bearsilverfox@comcast.com

Country Lane Construction150 Pine Knob RdNewville, PA 17241(717) 776-3033

CARPENTRY WORK

Brian Matthews2315 Spring RoadCarlisle, PA 17013Home: (717) 422-5560cell: (845) 417-4072bmatthewsww@gmail.com

Steve Wiser516 Middle RoadNewville, PACell: (717) 856-4946 Home: (717) 776-4764conoex516@gmail.com

GRAVEL AND SAND

Steve Wiser516 Middle RoadNewville, PACell: (717) 856-4946 Home: (717) 776-4764conoex516@gmail.com

VINTAGE REPRODUCTION HARDWARE AND FASTENERS

Van Dyke’s RestorersWebsite: https://www.vandykes.com/

House of Antique HardwareWebsite: https://www.houseofantiquehardware.com/

LANTERNS AND BRACKETS

W. T. Kirkman LanternsWebsite: https://www.lanternnet.com/

Avoid kerosene lanterns that have round globes. They did not originate until post-war. Chimney type globes were used prior to the 1920’s. Kirkman’s “No. 2 Champion Cold Blast” in galvanized finish is historically correct for the period, for example.

This list is compiled for 2019. Please check the list on the GWA website for future updates.

Part 7 – Preparing a cost estimate for the project

How much will it cost and can the unit raise enough money to pay for this? Can the unit provide the labor to build or will it be subcontracted out? Will the GWA be able to subsidize the excavation costs?

Questions such as these generally need to be answered as step one for any project to see if it is viable, and preparing a cost estimate is an important first step. This is a fairly simple procedure; an itemized list made on a pad of paper or on a PC spreadsheet or the like can be very helpful. Set up the estimate in chronological order of work such as in the following example. This example is an oversimplification but you can get the general idea.

Earthwork costs can be a significant amount of the total project cost. Towards that end, the GWA may subsidize all or part of the initial excavation cost, provided the materials to build are on hand. This is policy as of 2019 and can change in the future. Additional earthwork costs (such as any backfill needed at the end of the project, fine grading an the like) are borne by the unit.

Here are additional guidelines and tips that may be useful to prepare an accurate estimate:

Add extra material to your estimated quantities. There may be mistakes in the field, lumber cut to fit certain spaces, and usually some waste. Adding 10% extra materials is a good rule of thumb especially for smaller size lumber such as 2x4s or 1x planking. The last thing

needed when working at the site is to have to run to the lumber yard or metal supplier because something got cut wrong and there wasn’t enough extra material to replace it.

Board Foot – When dealing with sawmill lumber and getting a quotation, you should be familiar with the term board foot and its measurement because that is the unit by which rough sawn lumber is sold. A board foot is a unit of volume for timber equal to 144 cubic inches.

Hardware (nails, screws, lag bolts, hinges and the like) does not need to be itemized unless there is an anal-retentive reenactor desire to count every nut and bolt. A list-to-buy will be needed down the road for sure but for now, the overall cost can be calculated by a good carpenter rule of thumb: total all the material costs (lumber, metal, etc.) and add 15% of that amount for hardware. This number generally rings true. The cost of hardware may be surprisingly high at times. Steel is an expensive commodity.

Labor: This can be a significant cost item in the estimate when the work is to be subcontracted out, and is generally much greater than the total cost of all the materials. A unit that is able to build a project with volunteers can save significantly. When subcontractor work is involved, there is no rule of thumb to estimate the cost and units should obtain quotes for each project.

Add delivery fees and sales taxes. Several suppliers in the Newville area will deliver materials to the site for a fee, modest by city standards. Sales taxes in PA are 6%

A WORD ABOUT STRUCTURE SIZE:

When planning the measurements for the structure, take into account the standard lengths of lumber, which comes in 2-foot increment (with 8’, 12’ and 16’ the most common standard sizes) to maximize efficiency and reduce cutting and waste. A 12’ x 16’ structure, for example, would be more efficient and easier to construct than one, say, with a 13’ x 17’ footprint.

Sawmill lumber may be cut to any lengths but the precut sizes that pressure treated and any modern dimensional lumber comes in has these size limitations, which should be taken into consideration. The amount of time spent in the field cutting lumber to meet odd dimensions can sometimes be considerable and may be overlooked when planning and making drawings.

Part 8 – Completing the GWA construction application form

The on-line form is available as Appendix A in the GWA Site Regulations on the GWA web page.

This form can be linked here: http://www.greatwarassociation.com/Constructionapp.html

The form is fairly straightforward to fill out and complete. If a unit is not able to use the electronic format, they should contact their trenchmaster for an alternative method to submit the application. The old fashioned way of mailing in an application is still acceptable.

Here are instructions and tips for the online form:

Email: Whatever email address is inserted will automatically receive a copy of the completed application when the submit button is clicked.

Note that all fields in this form that are marked with an asterisk are required. The form cannot be submitted if any of these are left blank.

The project location must be specific; in other words “just north of our old bunker” is not an adequate description. Others who are not familiar with a unit’s area may review the form. Use language so that any GWA member can pinpoint the location at the site.

Adding a location image (which is optional) may be extremely helpful towards this end.

A jpeg image from your computer such as a map scan or Google earth image that shows the proposed location can be attached with this link.

In the example shown here, a Google earth image was copied and marked on.

Note A – Project plans and drawings are attached here if they are available electronically. The plans must include enough detailed information about the project’s construction to show that it meets the requirements of the GWA Site Regulations. The larger the project is (i.e. underground bunkers), the more detail that will be needed. Again, files from your computer are attached here.

If you are not able to send drawings electronically, they may be mailed to the trenchmaster for review. In that instance, please indicate that in the box above and contact the trenchmaster. The trenchmaster may also be able to assist with the preparation of drawings needed.

If the project is small, and does not require drawings, sufficient information should be filled in the Construction Details box to show that GWA requirements are met.

Excavation Plan description - Here are examples: “12 feet of trench needs to be dug, 6 feet wide and 8 feet deep”, or “16 ft. x 12 ft. x 8 ft. deep excavation required for bunker footprint, three sides to be backfilled upon completion. This work is to be done by [name].”

Drawings for the excavation work can also be attached if they are available and needed by the trenchmaster.

Materials: If the construction materials are described on the plans to be submitted, there is no need for detail here and in that case, note accordingly here. Otherwise, or for smaller projects where plans may not be needed, list all types of materials that will be used in the project. For example: “Rough-sawn oak to be used for framing and planking, corrugated metal panels to be used for sides, pressure treated lumber to be used for foundations”

The project timeline should include accurate, not wishful, information regarding the project start date and the projected finish date. Timelines that may interfere with GWA events could be a factor in the approval process. Note that approved applications are valid for a period of one year.

When you hit the submit bar, a copy is sent to the trenchmaster and to the email address entered on the form. This copy will have all attachments. It will be forwarded as an email by the trenchmaster to other members of the Site Committee; likewise, the unit recipient can forward his copy to other members in the unit with all attachments viewable.

* * *

Part 9 – Future Addenda

This CP Design Guide is a living document and may be continually edited and updated. The intent is to have construction drawings and designs from approved CP projects, and any documents regarding construction and/or design at the site to be added in the future. Please forward submissions to your Trench Master.

Acknowledgments: I’d like to thank Brian Matthews, carpenter extraordinaire for many of the tips and techniques used in this guide and all the members of my unit’s IR92 Pionier work crew whose skills, dedication and Kameradschaft at the site have been invaluable to the unit and to me. - George Walters “Ranger”