Advanced Framing - WoodWorks
Transcript of Advanced Framing - WoodWorks
2/6/2014
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Advanced Framing:
Balancing Structure, Energy, and Cost
Presented on February 26, 2014 by
Karyn Beebe, PE, LEED AP
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© The Wood Products Council 2014
“The Wood Products Council” is a
Registered Provider with The
American Institute of Architects
Continuing Education Systems
(AIA/CES), Provider #G516.
Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.
This course is registered with AIA CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.
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Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Course Description
As California marches towards net zero energy buildings,
architects and engineers are seeking cost-effective options that
maintain strength and durability of the structural system while
meeting energy-efficiency and other sustainability goals.
Advanced framing is a system of wood construction techniques
designed to optimize material use and increase energy efficiency.
The objective is to eliminate unnecessary lumber from the
framing process, reducing construction costs and thermal
bridging while increasing the amount of insulation that can
potentially be used to improve thermal performance of the
envelope.
Learning Objectives
1. Understand the structural nuances associated with creating a
direct load path with advanced framing techniques, including
stacked framing and lateral load transfer.
2. Discover advanced framing’s relationship to “green building” and
energy efficiency, including the potential for increased R-value
and minimization of thermal bridging.
3. Review aspects of advanced framing, including: 24” o.c. framing,
single top plates, ladder blocking at wall junctions, 2-stud corners,
correctly sized headers to openings in load-bearing walls only,
offset allowances with single or double top plates, avoiding
excessive framing at window openings, and raised heel trusses.
4. Discuss case studies illustrating the lumber and cost savings
associated with advanced framing in non-residential projects.
Agenda
1. What is Advanced Framing?
2. Why should one adopt Advanced Framing?
When?
3. How do you phase it into your project?
4. Challenges
5. Examples
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What is Advanced Framing?
(NOT Advanced Framing)
What is Advanced Framing?
(NOT Advanced Framing)
What is Advanced Framing?
(NOT Advanced Framing)
What is Advanced Framing?
(NOT Advanced Framing)
What is Advanced Framing?
a.k.a
Optimum Value Engineering
(O.V.E.) a.k.a
In-Line Framing a.k.a.
Stacked Framing
What is Advanced Framing?
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APA Construction Guide
Released February 2012
APA Form Number M400
What is Advanced Framing?
Suite of Framing Techniques
Advanced Framing is not a
“take all or leave all”
concept.
Using any or some of the
techniques is still
“Advanced”
The more holistic the
approach, the more savings.
What is Advanced Framing?
Why adopt Advanced Framing?
Energy Efficiency
Cost Effectiveness
Sustainability
Structural Integrity
Sacramento Habitat for Humanity: Net Zero Energy, 21 points beyond
LEED Platinum, Advanced Framing.
Why?
(Energy Efficiency)
“Title 24” – Part 6
California Energy Code
2013 Standard has been
delayed July 1st
Prescriptive v.
Performance
Climate Zone Changes
Why?
(Energy Efficiency)
NetZero Energy Goals for CA 2020 Residential/2030 Commercial
How do we get there?
Improve wall assemblies – Decrease air infiltration,
increase wall insulation, use thicker walls (2x6 framing)
Add renewable energy
Use ADVANCED FRAMING!
Why?
(Energy Efficiency)
Maximize space
for cavity
insulation
Minimize
insulation voids
Reduce thermal
bridging
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Why? (Energy Efficiency)
Energy Star 3 Thermal Enclosure System Rater Checklist
4.4.5 Advanced Framing, including all of the items below:
4.4.5a All corners insulated ≥ R-6 to edge 17, AND;
4.4.5b All headers above windows & doors insulated 18, AND;
4.4.5c Framing limited at all windows and doors 19, AND;
4.4.5d All interior/exterior wall intersections insulated to same R-value as the rest of
the exterior wall 20, AND;
4.4.5e Minimum stud spacing of 16" o.c. for 2x4 framing in all Climate Zones, and
in Climate Zones 5 – 8, 24" o.c. for 2x6 framing unless construction
documents specify other spacing is structurally required 21
4.4 Reduced thermal bridging at above-grade walls
separating conditioned from unconditioned space
(rim/band joists exempted) using one of the following
options: 12, 13
Why?
(Cost Effectiveness)
More resource efficient than conventional framing
Optimizing lumber usage reduces material costs
Reduced framing labor
Increase efficiency of
other trades:
Fewer studs for plumbers
and electricians to drill
Fewer cavities to fill
Less waste and dumpster
costs
WOOD FRAMED WALLS
2x6 – R-20 Cavity Insulation 2x4 – R13 Cavity + R-5 Foam
(Advanced Framing) (Conventional Framing)
System Issues Value
Impact System Issues
Value
Impact
More earthquake resistant
construction * + More susceptible to earthquakes - More energy efficient
(R17.3 – R17.8) + Less energy efficient
(R15.6 – R16.8) - Ease of future attachments to
exterior wall + More difficult for future attach to
exterior wall - Walls with less risk of trapping
moisture + Walls with greater risk of trapping
moisture -
*If fully sheathed with wood structural panels
Why?
(Cost Effectiveness)
WOOD FRAMED WALLS
2x6 – R-20 Cavity Insulation 2x4 – R13 Cavity + R-5 Foam
(Advanced Framing) (Conventional Framing)
System Issues Cost
Impact System Issues
Cost
Impact
Similar volume of wood
Advanced Framing 2x6 $
Similar volume of wood
Conventional 2x4 $
Reduced labor - $ Cavity insulation + foam + $
Cavity insulation only - $ More complex wall envelope + $
Continuous nail base for cladding - $ Complicates cladding attachment + $
Standard window installation - $ Complicates window attachment + $
Special extension jambs + $ Special extension jambs + $
Why?
(Cost Effectiveness)
Why?
(Sustainability)
Wood has long been a successful
green building strategy
Renewable resource
Less energy to manufacture
Less pollutants to manufacture
Performs well on life-cycle analysis
Advanced Framing delivers greater
environmental dividends
Optimizing material usage
Reducing construction waste
Why?
(Sustainability)
Green Codes/Certification Systems that reward
points to projects using Advanced Framing
techniques
LEED, LEED for Homes
CALGreen
Green Point Rated
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Why?
(Structural Integrity)
Stacked Framing provides direct
load path
2x6 studs @ 24" o.c. are 2-1/2
times stiffer than 2x4 studs @
16" o.c.*
Wall Bracing Solutions
Siding Attachment Solutions
* Moment of Inertia Comparison
How?
Phasing In Advanced Framing
1. Switch to 2x6 studs to increase cavity insulation
depth and R20 energy code requirements.
2. Change wall framing module from 16" o.c. to 24" o.c.
Retain the use of double top plates to avoid in-line
framing.
3. Incorporate intersecting wall techniques and energy
efficient corners, beginning with three-stud corners,
that allow for greater insulation volume. Implement
energy-efficient headers and single-member framing
around openings.
4. Eliminate double top plates.
Conventional Framing
16”o.c. Member Spacing
CONVENTIONAL 2x4 Studs at 16" o.c., Double top plate, 3-Stud corners,
FRAMING: 2-Stud ‘T’ junctions, Double 2x12 header on jack studs,
Redundant cripples at ends of window sill plate
Advanced Framing
24”o.c. Member Spacing
ADVANCED 2x6 Studs at 24"o.c., Single top plate, 2-Stud corners,
FRAMING: Ladder junctions, Wood structural panel headers,
Single studs at sides of openings, Redundant cripples omitted
Wall Frame Comparison
Single
top plate Wood structural panel
box or single-ply header
Single studs at
sides of opening
Ladder blocking
(optional)
Advanced
Framing
Conventional
Framing
Advanced/
Conventional
Framing
2x6 studs,
24"o.c.
Redundant cripple
studs eliminated
Two-stud corner or
California corner
Three-stud Corners
Insulated Three-stud Corner
(California Corner)
Outside corner
Difficult to
insulate
Traditional Corner
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Two-stud Corners
Outside corner
Drywall clip
to hold drywall
in place
Two-stud Corner
(with Drywall Clips)
Alternatives
2012 IRC,
Figure R602.3(2) FRAMING DETAILS Note: A third stud and/or
partition backing stud shall be
permitted to be omitted through
the use of wood back-up cleats,
metal drywall clips, or other
approved devices that will serve
as adequate backing for facing
materials.
Two-stud Corners
Corner stud
2x Ladder Blocking at 24"o.c.
or Drywall Clips
Outside corner
2x Ladder Blocking at 24"o.c.
or Drywall Clips
Interior Wall
Intersection Options
Ladder Junction Single top plate
3" x 6" x 0.036" galvanized steel plate
Interior wall
2x ladder blocking at 24"o.c.
Install blocking with wide face vertical
for maximum backing to wall finish and
for maximum insulation in exterior walls.
Interior Wall
Intersection Options
Junction for Continuous
Drywall Application
3" x 6" x 0.036" galvanized steel plate
Drywall
Interior stud set in ½ inch (or more)
from exterior wall studs
Detail courtesy of NAHB Research Center
Single
top plate
Openings
Non-Load-Bearing Walls
Conventional Headers Not Required
Opening in
non-load-
bearing
wall
Single top plate
Cripple studs as required
Opening top plate may be doubled for
openings wider than 8'
Single opening top plate
Note: Use jack studs as required.
Engineered Wood & Lumber Headers
2012 IRC Section R602.7.1
Single-Ply Header
at Top Plate
Top plate
Single-ply load-bearing header
(flush outer face of header with outer edge of studs)
Cavity insulation space
(to stud depth less single header thickness)
Header bottom plate
(to complete rough opening at header)
For many openings 4 feet wide or less in one-story
buildings, single studs at sides of rough openings
may be adequate. 2012 IRC Table R502.5(1).
Jack stud or approved framing connector
2012 IRC Tables R502.5(1) & R502.5(2)
Outside of wall
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Engineered Wood & Lumber Headers
2012 IRC Section R602.7.1
Single-Ply Header
with Cripple
Top plate
Single-ply load-bearing header
(flush outer face of header with outer edge of studs)
Cavity insulation space
(to stud depth less single header thickness)
Header bottom plate
(to complete rough opening at header)
For many openings 4 feet wide or less in one-story
buildings, single studs at sides of rough openings
may be adequate. 2012 IRC Table R502.5(1).
Jack stud or approved framing connector
2012 IRC Tables R502.5(1) & R502.5(2)
Outside of wall
Engineered Wood & Lumber Headers
Large Opening Single Headers
Top plate
Cavity insulation space
3-1/8" or 3-1/2" glued laminated timbers (glulams),
or multiple-ply structural composite lumber (SCL),
or sawn lumber header
Jack studs as required
Outside of wall
2012 IRC Section R602.7.1
Engineered Wood & Lumber Headers
Approved Framing Connector Option Single or Double-ply Headers
Cavity insulation space
Header hanger
(such as Simpson Strong-Tie HH or equivalent)
Single stud at sides of rough openings
(most openings up to 48" wide) outside
of wall
2012 IRC Section R602.7.1
Alternate Header Connection: Where the number of required jack studs equal one,
the header is permitted to be supported by an approved framing anchor attached to the full-height wall stud and to the header.
Wood Structural Panel Box Header
for Load-Bearing Walls
One-sided Wood Structural Panel Box Header
Single top plate
Cavity insulation space
(to full width of wall studs)
Drywall interior finished
Single stud at sides
of rough openings to 48" wide,
jack stud required span > 48"
Cripple studs on
stud layout
Min. 15/32
Performance
Category wood
structural panel
Header top plate
to complete rough
opening at header
Wood Structural Panel Box Header
for Load-Bearing Walls
The top plate of the wood structural panel box header shall be continuous over header.
For construction details and maximum spans, see 2012 IRC Section R602.7.2, Figure R602.7.2 and Table R602.7.2.
Two-Sided Wood Structural Panel Box Header
Insulation
Cripple studs on stud layout
Min. 15/32 Performance Category
wood structural panel or thicker
(sanded or MDO plywood may be used
on inside surface in lieu of drywall)
Note: Framing fastening per code.
Wood Structural Panel Box Header
for Load-Bearing Walls
Nail Pattern Single top plate
Wood structural panel face shall be
single piece of 15/32 Performance
Category or greater sheathing
Slant nail if necessary
Cavity insulation space
behind wood structural panel
Single stud at sides of
rough opening to 48" wide
Jack stud required if span > 48"
3" 3" 3"
9“
or
15”
depth
NAIL PATTERN
2012 IRC, Table R602.7.2 8d common nails
minimum 3"o.c. spacing
stagger nails ½"
Strength Axis
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Wood Structural Panel Box Header
for Load-Bearing Walls
TABLE R602.7.2* MAXIMUM SPANS FOR WOOD STRUCTURAL PANEL BOX HEADERS
HEADER
CONSTRUCTION
HEADER
DEPTH
HOUSE DEPTH (feet)
24 26 28 30 32
Wood Structural
panel – one side
9" 4' 4' 3' 3' -
15" 5' 5' 4' 3' 3'
Wood Structural
panel – both sides
9" 7' 5' 5' 4' 3'
15" 8' 8' 7' 7' 6'
* Spans are based on single story house with clear span trussed roof or two-story
with floor and roof supported by interior-bearing walls.
Wood Structural Panel Box Header
Energy Heel Truss to Wall
Wood Structural Panel Overlap
Energy heel truss
Fastening per design
Optional rafter-tie or tension strap
inside or over wall sheathing per
manufacturer recommendation
Plywood or OSB wall sheathing
Ensure correct fastening of
sheathing to top plate per shear
wall, wall bracing, or combined
shear and uplift requirements.*
*See rafter-tie manufacturer’s instructions for installation of strap over sheathing and into framing.
Ceiling Frame – Attic Insulation
Typical Attic Insulation with “Regular Heel”
R-30 = 10" Insulatable depth
at rafter heel
Minimum 1" space between
insulation and roof sheathing
R-38 = 12"
R-49 = 15"
2009 IRC, N1102.2.1 or 2009 IECC, 402.2.1
Ceilings with attic spaces. When Section N1102.1
would require R-38 in the ceiling, R-30 shall be deemed to
satisfy the requirement for R-38 whenever the full height
of uncompressed R-30 insulation extends over the wall
top plate at the eaves. Similarly, R-38 shall be deemed to
satisfy the requirement for R-49…….
Ceiling Frame – Attic Insulation
Typical Attic Insulation with “Energy Heel”
R-30 = 10"
Insulatable depth
at truss heel
Minimum 1" space between
insulation and roof sheathing
R-49 = 15"
R-38 = 12"
Rough Opening Placement
The placement of openings in
load-bearing walls and the layout
of framing members above
openings have significant impact
on header sizing for
advanced framing.
Minimum required materials
to frame rough opening
Structure above imposing
tributary loads on header
Potential increased header
size - increased load from structure above
Excess materials due to
inefficient opening
placement
Best
Placement
36" wide
opening
36" wide
opening
36" wide
opening
24" wide
tributary load
24" wide
tributary load
48" wide
tributary load
Note: Jack studs may not be required if using wood structural panel headers.
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Double Top Plate Offsets
(2x4 Framing)
2012 IRC Section R602.3.3 Bearing studs. Where joists, trusses or rafters are spaced more
than 16 inches o.c. and the bearing studs below are spaced 24 inches o.c., such members
shall bear within 5 inches of studs beneath.
Prescriptive Member Placement for
Double Top Plate Wall Construction
Trusses spaced > 16"o.c.
Studs at 24"o.c.
2x4 top plate maximum offset,
Max. offset = 5"
Max. offset = 5"
Double Top Plate Offsets
(2x6 Framing)
2012 IRC Section R602.3.3 Bearing studs. Where joists, trusses or rafters are spaced more
than 16 inches o.c. and the bearing studs below are spaced 24 inches o.c., such members
shall bear within 5 inches of studs beneath.
Exception: 1. The top plates are two 2x6 inch or two 3x4 members.
Prescriptive Member Placement for
Double Top Plates with 2x6 Walls
Truss
Studs at 24"o.c.
2x6 top plate no maximum offset
No Maximum Offset
Single Top Plate
Offsets
2012 IRC Section R602.3.2 Top plate. Wood studs shall be capped with a double top plate...
Exception: A single top plate may be installed in stud walls…provided the rafters or joists
are centered over the studs with a tolerance of no more than 1 inch…
Prescriptive Member Placement for
Single Top Plate Wall Construction
Common/repetitive members supporting
uniform loads applied to single top plate
Trusses or floor joists at 24"o.c.
Studs at 24"o.c.
1" 1"
Single Top Plate
Offsets
2012 IRC Section R602.3.2 Top plate. Wood studs shall be capped with a double top plate...
Exception: A single top plate may be installed in stud walls…provided the rafters or joists
are centered over the studs with a tolerance of no more than 1 inch…
Prescriptive Member Placement for
Single Top Plate Wall Construction
Rafter
Ceiling joists
Studs at 24"o.c.
1" 1"
Single Top Plate Connections
Longitudinal Top Plate Splice
3" x 12" x 0.036" Galvanized steel plate
12- 8d (2-1/2" x 0.113") Nails each side*
Prescriptive Connection
*Plate size and number of fasteners required is
greater than 2009 International Residential Code.
Single Top Plate Connections
8-16d (3-1/2" x 0.135") nails
each side of splice.
Alternate Connection:
Wood Splice
Splice Joint
Single top plate
Splice joint
Longitudinal Top Plate Splice
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Single Top Plate Connections
Intersecting Wall Connection
3" x 6" x 0.036" galvanized steel plate
6-8d (2-1/2" x 0.113") nails each side
2012 IRC, Section R602.3.2
2x6 lumber splice
2-10d (3" x 0.128") nails each side
2012 IRC, Table R602.3(1), Item 19
Prescriptive Connection Alternate Connection
Single Top Plate Connections
Corner Framing
3" x 6" x 0.036" galvanized steel plate
6-8d (2-1/2" x 0.113") nails each side
2012 IRC, Section R602.3.2
2x6 lumber splice
2-10d (3" x 0.128") nails each side
2012 IRC, Table R602.3(1), Item 19
Prescriptive Connection Alternate Connection
Challenges
Wall Sheathing Installation
• Fasten panels as recommended with 8d nails
• 6" o.c. at all panel edges
• 12" o.c. in the field
• Space panels 1/8" at all panel ends and edges
• Use minimum 7/16 category panels
• Some OSB panels alter strength-axis orientation
to allow vertical placement with strength axis
across studs
Recommendations for 24" o.c. studs
Recommended WSP for
Stucco Exterior Finish
Stud
Spacing
Panel
Orientation
APA Rated Sheathing
Performance Category Span Rating
16" Horizontal 3/8 24/0
Vertical 7/16 Structural 1 OSB 24/16
15/32, 1/2 5-ply or OSB 32/16
24" Horizontal 7/16 24/16
Vertical 19/32, 5/8 5-ply or OSB 40/20
• Blocking recommended between studs along horizontal panel
joints
Wood's Strength Direction
Arrow
Optional
Str
en
gth
Axis
Strength
Axis
Arrow
Required
Common Not Common
Strength Axis
48" 48"
Building Elements: Panels
Cross Face Panels “Strength Axis This Direction”
Strength in Short Direction for
Vertical Installation
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Whole House Design
In new home construction, the walls of a
house also present a great opportunity to protect
the house from the forces of nature Whole House Design
Whole House Design
In new home construction, the walls of
a house present a great opportunity
to prevent energy loss
Examples
Examples
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Your Next Advanced Framing Project
U.S.A.
Looking for Opportunities to Assist Builders with
Advanced Framing and Build Case Studies
All-wood Podiums in Mid-rise
Construction
Oceano at Warner Center
4 Story over 1 wood podium
structure
244 units
City of Los Angeles
(APA Case Study N110)
All-wood Podiums in Mid-rise
Construction
Panelization & BIM
Framer works closely with design
team from project inception
Emphasis on Stacking
Avoid 80-90% field issues
preconstruction
Cost savings – waste reduction
and faster construction schedule
Burden is on the builder to
produce structures that are:
1. Cost-effective to build
2. Strong and safe
3. Energy-efficient and
environmentally-friendly
Balancing Cost,
Structure and Energy
Customer Satisfaction
APA Web Site: apawood.org
CAD Details
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Questions?
Karyn Beebe, PE, LEED AP
(858) 668-7161
This concludes The American Institute of Architects
Continuing Education Systems Course