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October 8, 2015
2016 Code Readiness
Advanced Wall Construction
Pacific Gas and Electric Territory
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Sponsored by PG&E
These programs are funded by California utility customers and administered by PG&E under the auspices of the California Public Utilities Commission.
“PG&E” refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation. © 2014 Pacific Gas and Electric Company. All rights reserved.
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Program Overviews
Drive energy efficient design and construction through incentives and design assistance– California Advanced Homes Program (CAHP): single family– California Multi‐Family New Homes (CMFNH): multifamily
Programs target two CPUC goals: – By 2015: 90% of new homes at least 20% better than 2008 code– By 2020: 100% of new homes to reach Zero Net Energy (ZNE)
Program is funded under the auspices of the CPUC– Programs may revise incentive levels and requirements during
the program cycle– Ratepayer funded, public service
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Upcoming Events
We look forward to continuing the conversation!
October 16‐18th Monterey Design Conference:Pacific Grove, CA
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Advanced Wall Construction
Panelist:David Heslam, Earth Advantage
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WELCOME
David HeslamExecutive Director
Earth Advantageearthadvantage.org
Agenda
1. Wall Assemblies2. Moisture Management3. Cost Comparisons
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Learning Objectives
– Discuss assembly U‐Factor of 0.065 in all climate zones– Understand which wall assemblies comply with the 2016 Title
24 Prescriptive Code– Review issues for implementing necessary changes in your
projects– Insure effective moisture management for high performance
wall assemblies– Review alternative high R value wall assemblies which comply
with 2016 Code
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Wall Assemblies
1. Title 24 standards2. Assembly options
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2013 Code versus 2016 Code Standards
2013 Code: Residential Package A Prescriptive Standard– Assembly U‐Factor of 0.065 in all climate zones– Typically : R‐15 + 4, 2x4 @ 16oc or R‐19 + 2, 2x6 @ 16oc
2016 Code: Residential Package A Prescriptive Standard– Assembly U‐Factor of 0.051 in all climate zones except CZ 6 & 7
Prescriptive change: performance tradeoffs will be possible and common.
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Wall Assembly Table 1
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Wall Assembly Table 2
Most likely to be used in Production Housing– Wall Framing Options
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**Multiple combinations of similar materials will achieve these same U‐factors
U‐factor FramingStud
SpacingCavity
Insulation Exterior Insulation Cavity Insulation Type
0.050 2x6 24” OC R‐19 R‐4 (1") Low density fiberglass batt
0.049 2x6 16” OC R‐21 R‐4 (1") High density batt or BIB
0.048 2x6 16” OC R‐19 R‐6 (1.25") Low density fiberglass batt
0.049 2x4 16” OC R‐15 R‐8 (2") High density batt
Wall Upgrades: Advantages and Disadvantages
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– Water vapor control– Super Insulation– Greenhouse gases
– Labor cost– Material cost
– Planning– Floor plan– Dimensional changes– Trades Coordination
– Wavy siding and drywall– Furring details– Siding and trim details– Cavity insulation quality– Air sealing typical– Weather barrier details
Low density fiberglass batt – Option 1
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U‐factor FramingStud
SpacingCavity
Insulation Exterior Insulation Cavity Insulation Type
0.050 2x6 24” OC R‐19 R‐4 (1") Low density fiberglass batt
Planning ‐Floor plan ‐Dimensional changes ‐Trades Coordination ‐Wavy siding and drywall ‐Furring details +Siding and trim details +Cavity insulation quality ‐Air sealing typical +Weather barrier details +
Water vapor control +Super Insulation ‐Greenhouse gases ‐
High Density Fiberglass Batt – Option 2
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U‐factor FramingStud
SpacingCavity
Insulation Exterior Insulation Cavity Insulation Type
0.049 2x6 16” OC R‐21 R‐4 (1") High density batt or BIB
Planning ‐Floor plan ‐Dimensional changes ‐Trades Coordination ‐Wavy siding and drywall +Furring details +Siding and trim details +Cavity insulation quality ‐Air sealing typical +Weather barrier details +
Water vapor control +Super Insulation ‐Greenhouse gases ‐
Low Density Fiberglass Batt – Option 2
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U‐factor FramingStud
SpacingCavity
Insulation Exterior Insulation Cavity Insulation Type
0.048 2x6 16” OC R‐19 R‐6 (1.25") Low density fiberglass batt
Planning ‐Floor plan ‐Dimensional changes ‐Trades Coordination ‐Wavy siding and drywall +Furring details ‐Siding and trim details ‐Cavity insulation quality ‐Air sealing typical +Weather barrier details +
Water vapor control +Super Insulation ‐Greenhouse gases ‐
High Density Fiberglass Batt – Option 2
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U‐factor FramingStud
SpacingCavity
Insulation Exterior Insulation Cavity Insulation Type
0.049 2x4 16” OC R‐15 R‐8 (2") High density batt
Planning +Floor plan +Dimensional changes +Trades Coordination ‐Wavy siding and drywall +Furring details ‐ ‐Siding and trim details ‐Cavity insulation quality ‐Air sealing typical +Weather barrier details +
Water vapor control +Super Insulation ‐Greenhouse gases ‐
Staggered Stud Wall
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Staggered Stud Wall
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Planning ‐Floor plan ‐Dimensional changes ‐Trades Coordination ‐Wavy siding and drywall ‐Furring details +Siding and trim details +Cavity insulation quality +Air sealing typical +Weather barrier details +
Water vapor control ‐Super Insulation +Greenhouse gases +
Double Stud Wall
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Double Stud Wall
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Planning ‐Floor plan ‐Dimensional changes ‐Trades Coordination ‐Wavy siding and drywall ‐Furring details +Siding and trim details +Cavity insulation quality +Air sealing typical ‐Weather barrier details +
Water vapor control ‐Super Insulation +Greenhouse gases +
Ply‐On‐Foam (aka Thermally Broken) Shear Wall
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Site built advanced nailing 16d @ 3”
AdvantagesFurring details +Siding and trim details +Weather barrier details +
Ply‐On‐Foam Product Example
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10d nails @ 4” for panels having 1" of insulation
Additional resources:– Building Green Portland– Ply‐on‐foam walls increase
energy efficiency
Moisture Management
1. Exterior water management2. Interior water management3. Drying potential
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Moisture Management
High R value walls are vulnerable to condensation
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Exterior Bulk Water Management
Best Practices– Flashing of all penetrations to the primary weather resistive
barrier (WRB). – Bond break at minimum so WRB is not coated with stucco– Provide a drainage gap for bulk water and solar driven vapor
moisture that can occur on stucco after wind driven rain.
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Exterior Bulk Water Management ‐ Drainage Gap
Drainage Gap Options– Delta‐Dry– Mortairvent mortar deflection and ventilation system– Home Slicker Stone & Stucco rainscreen– Korax Stucco Rainscreen Panel– WaterWay rainscreen drainage mat
Further Reading on Green Building Advisor: – To Install Stucco Right, Include an Air Gap
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Exterior Bulk Water Management ‐ Lap Siding
Best Practice– Build a ventilated rain screen
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Prevent Interior Moisture Migration
– Implement impeccable air sealing in the walls from the interior.– Air leakage of moist interior air into the walls has the highest
potential for moisture delivery into the walls. 90x higher
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Image Source: Lstiburek, Joseph. Mixed-Humid Climates. Eden Prairie, MN: EEBA, 2005
Drying Potential of Assemblies
Walls must have drying potential and vapor permeable in one direction, drying to the inside or outside
Best practice is to be vapor permeable in both directions– If you use a product with a Perm Rating of <0.1 it is not vapor
permeable and you are shutting down drying in that direction
Be careful when choosing exterior foam products. – Perm Ratings vary with thickness of foam. Ratings are given per
inch, 2” of foam halves the perm rating.– If exterior rigid on the outside is impermeable make sure your
wall can dry to the inside. Use inside:– Vapor semi‐impermeable PVA primer and latex paint or– Smart vapor retarder31
Perm Ratings of Materials
Permeability Perm Rating Range Materials
Class I
Vapor impermeable
<0.1 perm rubber, polyethylene, glass, alum. foil, sheet metal, foil faced polyisocyanurate insulation
Class II
Vapor semi‐impermeable
0.1 to 1.0 perm oil‐based paints, un‐faced extruded polystyrene XPS > 1‐inch, PVA primer + 2 coats of latex
Class III
Vapor semi‐permeable
1.0 to 10 perm plywood, bitumen impregnated kraft paper, OSB, extruded polystyrene XPS < 1‐inch, expanded polystyrene EPS, 30‐pound building paper
Class IV
Vapor permeable
> 10 permunpainted gypsum board, un‐faced fiberglass batt, cellulose insulation, some latex paints, 15 pound
building paper, house wraps
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Interior Drying Potential of Assemblies
Smart vapor retarders– Change permeability based upon relative humidity
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Images: http://foursevenfive.com and http://www.certainteed.com/
Interior Drying Potential of Assemblies
Hydroscopic materials– Change to a higher permeability rating when wet
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Cost Considerations
1. New cost study2. Cost comparison
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Cost Considerations
How do these options compare?– A recent study takes a look at cost considerations for various
wall assemblies
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Unit Costs Comparison
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* 2010 Costs Portland, Oregon
Wall Framing Exterior Sheathing
Cavity Insulation
Exterior Insulation
Water/Air Control Layer
Vapor Control Layer
Detailing at Openings
Total $/sf
1 2x6 @ 16 oc$3.73
½” plywd
$0.77
R‐21 FGbatt$0.49
None
$0.00
SBPOsheet$0.49
Smart retarder$.078
Casing + head flashing$0.54 $6.79
3 2x6 @ 24 oc$3.61
½” plywd
$0.77
R‐21 FGbatt$0.49
1” XPS
$1.86
SBPOsheet$0.49
none Casing + head flashing$0.76 $7.92
4 2x6 @ 24 oc$3.61
½” plywd
$0.77
R‐21 FGbatt$0.49
1” XPS
$2.46
SBPOsheet$0.49
none Casing + head flashing$1.09 $8.85
5 2x6 @ 24 oc$3.61
½” plywd
$0.77
R‐21 FGbatt$0.49
4” XPS
$5.17
SBPOsheet$0.49
none Casing + head flashing$1.21 $11.68
Example unit costs from the High R Walls study
Comparison Matrix of Fifteen Assembly Options
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Additional Resources
Building America Solution Center– FREE: CAD files, images, case studies, design guides
Building Science Corporation– Advanced design guides, including: A Hygrothermal Analysis of
Various Exterior Wall Systems
PG&E’s Pacific Energy Center – Classes, resource library
Hammer and Hand– Free Design Guides
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Questions?
Thank you!
CMFNH:[email protected] Hartkopf
Scott KesslerShannon Todd
CAHP:[email protected]
Matthew ChristieKevin Robison
Michelle Waffle‐OteroDeborah Hayman
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(866) 352‐7457