CHAPTER 14 Wall Systems Copyright Goodheart-Willcox Co., Inc. May not be posted to a publicly...

CHAPTER14Wall Systems

Copyright Goodheart-Willcox Co., Inc. May not be posted to a publicly accessible website.

• Describe different types of masonry wall systems.• Explain the use of ties, flashing, weep holes,

lintels, sills, jambs, and expansion joints in masonry wall systems.

• Explain the effects of moisture condensation in masonry walls and the methods used to resist condensation.

Objectives


• Describe construction procedures for thin brick veneer, including thin bed set, thick bed set, and precast panels.

• Explain the design, function, and construction of arches.

• Describe the joints used for movement in masonry.• Understand the function of caps and copings.• Install a retaining wall.

Objectives (Cont.)


• Single-wythe or multiple-wythe• Reinforced or unreinforced• Provide excellent structural performance• Easily maintained and attractive• Energy efficient due to high thermal mass

Masonry Walls


• Most energy codes specify U-values– Heat flow through a building product based on difference

between external and internal temperatures– R-value is thermal resistance of heat loss through a

building product– R = 1/U

Energy Codes


• Loadbearing or nonloadbearing

Solid Masonry Walls


6″ Masonry Walls with SCR brick

• SCR brick• Nominal thickness of

2 2/3″ produces 16″ in six courses

• Nominal 6″ wide and 12″ long


• Exterior nonloadbearing walls• Curtain walls

– Not wholly supported at each story

• Panel walls– Supported at each story and self-supporting between

stories

• Both types must be able to resist lateral forces

Four-Inch RBM Curtain and Panel Walls


Design of Four-Inch Walls

• Partially reinforced• Ladder- or truss-type

reinforcement• Drainage space on inside

of wall• Expansion joints

Brick Industry Association


• Walls built using solid or hollow masonry units• Separated to form inner and outer wall• Two types

– Cavity walls– Masonry bonded walls

Hollow Masonry Walls


Cavity Walls

• Widely used in low- and high-rise buildings

• Superior rain penetration resistance, thermal capabilities, sound transmission, and fire resistance

• Continuous air space2″ to 3″ wide


• Exterior wythe– Usually a nominal 4″ thick– Solid or hollow brick

• Interior wythe– 4″, 6″, or 8″ thick– Brick, structural clay tile, or hollow or solid concrete

masonry units

Construction of Cavity Walls


• Air space has insulation value and can be filled with insulation material for added reduction of heat transfer

• Acts as a barrier to moisture• Must be kept free of mortar droppings

Cavity


Weep Holes

• Required at bottom of cavity wall

• Mortar opening creates void for moisture inside wall cavity to exit

• Located immediately above flashing


Flashing

• Thin, impervious material • Usually made of metal• Keeps any moisture that

might collect in cavity away from inner wall

Portland Cement Association


Insulation

• Rigid boards installed horizontally within air space against cavity face of backup wythe

• Granular fill is usually poured directly into cavity from bag or from hopper



• Adjacent wythes tied together with corrosion-resistant 3/16″ diameter steel or metal ties

• Ties in alternate courses should be staggered• End of ties should be bent to 90° angles• Additional ties needed at openings

Bonding


• Diverts moisture out of cavity through weep holes• Continuous flashing at bottom of cavity and wherever

cavity is interrupted• Over unprotected wall openings• At window sills, parapet walls, and spandrels

Flashing


• Must be provided wherever flashing is used• Located in joints of outer wythe immediately above

flashing• Spacing is approximately 2′ O.C maximum

– Weep holes using wick material should be 16″ O.C. maximum

Weep Holes


• Movement of outer brick wythe is greater than that in solid or composite walls

• Expansion joints are recommended through outer wythe on each side of external corner where walls are 50′ or more in length

Expansion Joints


Hollow Masonry Bonded Walls

• Used as foundation and exterior loadbearing walls

• Not resistant to high moisture


Anchored Veneered Walls

• Brick and stone masonry facing veneer

• Veneer is attached, but not bonded to, backing

• Veneer does not act structurally with rest of wall


• Nominal 3″ or 4″ thick exterior brick wythe is anchored to backing system with metal ties

• Clear air space between veneer and backing• Wood frame, steel frame, concrete, or masonry backing

system• Facing of masonry units or other weather-resisting,

noncombustible materials

Anchored Brick Veneer Construction


• Brick veneer wall assemblies are drainage-type walls that resist rain penetration

• Flashing and weep holes work with air space to resist moisture penetration

• Brick veneer with wood or metal frame backing is usually built with minimum 1″ air space

Moisture Resistance


• Brick veneer on frame backing transfers weight of veneer to foundation

• Foundation brick ledge supporting brick veneer should be at least equal to total thickness of wall assembly

• Foundations must extend beneath frost line

Brick Veneer Foundations


Masonry Wall Ties

• Noncorrosive metal ties– One tie for every 2 2/3 sq ft

of wall area– Maximum spacing of

24″ O.C. in either direction

• Nail must be located within 5/8″ of bend in tie



• Must be embedded at least 5/8″ into bed joint from air space

• At least 5/8″ cover of mortar to exposed face• Corrugated ties must penetrate to at least half the

veneer thickness and have at least 5/8″ mortar cover

Wire Ties


Flashing and Weep Holes

• Position above grade– As close as possible to

bottom of wall– As close as possible above

openings and below sills

• Weep holes should be in head joints directly above flashing

• Weep hole spacing– No more than 24″ O.C. for

holes in which mortar has been completely removed

– Maximum of 16″ O.C. for holes with wicking material


Lintels

• Brick veneer backed by wood or metal frame must be supported by lintels over openings

• Lintel materials– Loose steel– Stone– Precast– Concrete– Cast stone– Reinforced brick


• May be needed to allow for horizontal movement• Required in brick veneer when there are

– Long walls– Walls with returns– Large openings

Expansion Joints


Composite Walls

• Two walls bonded together with masonry or wire ties

• Vertical collar joint (narrow space between facing and backup units) prevents passage of water


• First course of facing may be either headers or stretchers

• All facing courses are laid in a full mortar bed with head joints completely filled

• Facing headers are laid every seventh course• Mortar extruded on backside should be cut flush with

trowel before it hardens

Building an 8″ Composite Wall


• Wythes can be bonded across collar joint by parging backside of facing

Building an 8″ Composite Wall (Cont.)

Portland Cement Association


12″ Composite Wall

• Facing header course is laid overlapping the header block

• Header block can be laid with recessed notch up or down


• Water affects many building materials• Condensation can be decreased through ventilation or

dehumidification• Mechanical devices and heat exchangers remove

moisture-laden air

Resisting Moisture Condensation


Reinforced Masonry Walls

• Steel reinforcement embedded in masonry units

• Structurally bonded by grout core– Grouting techniques vary

• Full bed joints are used


Reinforcing Masonry Walls

• Maximum spacing of principal reinforcement should not exceed 48″

• Primary use of steel reinforcement is in vertical members, lintels, and bond beams


Retaining Walls

• Reinforced masonry• Two common designs

– Gravity– Cantilever

Cantilever-Type


• Single- or multi-wythe• Similar to reinforced masonry walls but without

reinforcements• Grout is added to core in loadbearing masonry walls to

provide added strength• Other uses include filling bond beams and collar joint in

two-wythe walls

Grouted Masonry Walls


• Thin brick units approximately 1/2″ to 1″ thick• Give appearance of conventional brick wall• Most common face size has nominal dimensions of

2 2/3″ × 8″• Adhered veneer

Thin Brick Veneer


• Thin bed set

Thin Brick Veneer Classifications



• Thick bed set

Thin Brick Veneer Classifications (Cont.)



Thin Brick Faced Precast Panels

• Forming table creates size and shape of wall panel

• Thin brick composes exterior face of panel, becomes bonded and embedded into panel when concrete mix is poured into form

• Constructed indoors and delivered to site

Gage Brothers in Sioux Falls, SD


• Horizontal or vertical spaces for plumbing, heating ducts, electrical wiring, etc.

• Chases are located inside of wall and are from 4″ to 12″ in width

• Recesses are limited to 1/3 of wall thickness

Chases and Recesses


• Structural member placed wall opening to support loads above– Steel lintels should be supported on either side of

opening for at least 4″– Reinforced concrete lintels should have a minimum

bearing of at least 8″ at each end– Longer lintels should have greater bearing surfaces at

ends

Lintels


Types of Lintels


• Brick masonry lintel with stirrups

Detailed Brick Masonry Lintel



• Slight movement occurs at location of lintels• Control joints are often located at ends• Noncorroding metal plate is placed under ends where

control joints occur to prevent uncontrolled cracking• Full bed of mortar should be used over plate

Movement at Lintels


• Masonry units span an opening by transferring vertical loads laterally to adjacent masonry units, and thus to abutments

Arches


Arch Terminology


• Arches are normally classified by:– Curve of intrados– Function, shape, style

• Arches are also classified as major and minor

Arch Classifications


Types of Arches



Types of Arches (Cont.)



Function of Arches

• Compression stresses are distributed through arch

• Weight is diverted to abutments

• Some may require steel reinforcements



• Odd number of units are used so keystone falls at center of crown

• Arch voussoirs are usually in radial orientation• Different shapes and sizes of brick selected based on

arch type, dimension, and desired appearance

Arch Design


Arch Spans

• Short spans– Tapered brick is

recommended to avoid wide mortar joints at extrados

• Larger spans– Requires less taper of the

voussoirs– Formed with rectangular

brick and tapered mortar joints

– Mortar joint should be between 1/8″ and 3/4″


• Dimension of arch at skewback that is perpendicular to arch axis, except in jack arches

• Depends on size and orientation of brick used• Usually a multiple of the brick’s width• Arch depth should increase with increasing arch span

Arch Depth


• Two methods– Special shapes and uniform joint thickness– Units of uniform thickness with varying joint thickness

• All mortar joints must be completely filled

Brick Masonry Arch Construction


Centering for Arches

• Temporary shoring supports masonry

• Centering is usually made from wood


Jack Arch Construction

• Supported by steel if opening is over 2′ wide

• Steel must be bent to the camber

• Each joint should be same width as entire length of joint

• End joints are horizontal to radius of arch


Segmental Arch Construction

• Number of courses is determined by length of extrados

• Size of brick is determined by length of intrados

• Rise should be 1/6, 1/8, 1/10, or 1/12 of span


Window and Door Details

• Details are necessary for mason to plan ahead

• Relationships between head, jambs, and sill to masonry wall



Sills

• Channel water away from a building

• Single or multiple units• Built in place or

prefabricated• Made of cut stone, brick,

concrete, or metal


Joints for Movement in Masonry

• Volume changes in masonry material result in movement

• Joints allow for movement to occur and to prevent cracks

• Types– Expansion joints– Control joints– Building expansion joints– Construction joints


Expansion Joints

• Separate brick masonry into segments

• Prevent cracking due to changes in temperature, moisture expansion, elastic deformation, and creep

• Horizontal or vertical

• Located so as not to compromise structural integrity



• Creates a plane of weakness in concrete masonry to control location of cracks

• Vertical opening through concrete masonry wythe• Must be located so structural integrity of concrete

masonry is not affected

Control Joint


• Divides building into separate sections so stresses developed in one section do not affect integrity of remainder of structure

• Through-the-building joint allows adjoining parts of building to move freely from one another

Building Expansion (Isolation) Joint


• Used where masonry work is interrupted• Mason terminates work at a vertical plane and then

continues laying brick until that section of wall is complete

• Next section of wall begins at construction joint• Located where least likely to impair strength

Construction (Cold) Joint


• Prevent cracks due to differences in expansion and contraction rates of materials

• Building paper or flashing separate two surfaces of masonry material

• Used between floor slabs and foundations• Allow each element to move somewhat independently

while providing support

Bond Breaks


• Enclose a building• Provide attractive appearance• Large soffits requires expensive forming and shoring• Brick masonry soffit may be more efficient for small

soffit area• Usually reinforced and grouted

Brick Masonry Soffits


Stone Quoins

• Large square stones used at corners and around openings of building for ornamental purposes

• Height is odd number of brick courses

• Length is equal to one or more units used in wall


• Freestanding structures– Straight walls– Pier and panel walls– Serpentine walls

• Can be perforated

Garden Walls


• Masonry texture and color give character• Thickness provides lateral stability against wind and

impact loads• Different copings

Straight Walls


• Series of relatively thin panels 4′ thick, braced by masonry piers

• Easy to build and economical• Ideal for uneven terrain• Foundations are required only for piers

Pier and Panel Walls


Serpentine Walls

• Serpentine shape provides lateral strength so wall can be built 4″ thick

• Radius of curvature no more than twice height above grade

• Depth no less than 1/2 of height


• Channel water away from building– Cap is covering within height of wall– Coping is covering at top of wall

• Single or multiple units• Tops slope in one direction or both directions• Made of brick, precast or cast-in-place concrete, stone,

metal, or terra cotta

Caps and Copings


• Shelf or ledge formed by projecting successive courses of masonry out from face of wall

• Used to achieve a particular appearance or to provide structural support

• Horizontal projection should not exceed 1/2 thickness of wall or veneer

• Projection of single course should not exceed 1/2 of unit height or 1/3 of unit bed depth

Corbels


• Masonry in which successive courses are stepped back from face of wall

• When racking back to achieve desired dimensions, make sure cores of units are not exposed

Racking


Segmental Retaining Walls (SRW)and Hardscape

• Constructed of high-strength concrete blocks or units made for dry stacking

• SRW blocks are used to build retaining walls

• Hardscape is intended for decorative purposes

Anchor Wall Systems, Inc.


Retaining Wall Products

• Some have locking lip on lower back edge

• Prevent forward movement exerted by earth pressures

• Straight and beveled front units with uniform or tapered widths


Retaining Wall Installation

• Prior to construction, prepare a layout plan that considers topography, drainage patterns, soil conditions, and local code restrictions

CHAPTER 14 Wall Systems Copyright Goodheart-Willcox Co., Inc. May not be posted to a publicly...

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