Building Enclosure Design Fundamentals, Components, and Assemblies COLIN SHANE M.ENG., P.ENG., P.E. PRINCIPAL, SENIOR PROJECT MANAGER RDH BUILDING SCIENCE INC. JULY 11, 2018 Disclaimer: This presentation was developed by a third party and is not funded by WoodWorks or the Softwood Lumber Board. 1 of 63
Copyright Materials This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. RDH Building Sciences Inc. 2015
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. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Course Description Building enclosures are responsible for controlling heat flow, air flow, vapor flow and a number of other elements. Through a combination of building science fundamentals and current research, this presentation will explore design considerations associated with wood-frame building enclosures and the role of control layers. Discussion will focus on best practices for designing durable, energy-efficient enclosures using traditional light wood-frame construction.
Learning Objectives Review building science fundamentals and building enclosure design considerations for light wood-frame buildings. Explore the role of control layers in building enclosures for elements such as heat flow, bulk water intrusion and air flow. Discuss best practices for light wood-frame building enclosure design, detailing, and construction techniques. Explore the thermal benefits of utilizing wood-frame construction.
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 6 of 97
Wood-frame Building Enclosure Design Guides 2011 Building Enclosure Design Guide Wood-frame Multi-Unit Residential Buildings Emphasis on best practices, moisture and new energy codes 2013 Guide for Designing Energy- Efficient Building Enclosures Focus on highly insulated woodframe assemblies to meet current and upcoming energy codes CLT Handbook 7 of 63
Building Enclosure Design Fundamentals Support Control Finish Structural loads Heat flow Air flow Vapor diffusion Water penetration Condensation Light and solar radiation Noise, fire, and smoke Being durable and maintainable Being economical & constructible Looking good! 8 of 63
The Old Way 9 of 63
The New Way Light & Tight 10 of 63
Trends in Building Enclosure Design Trend towards more energy efficiently building enclosures Air barriers now required in 2012 IECC Continuous insulation becoming more common More insulation = less heat flow to dry out moisture Marginal assemblies that worked in the past may no longer work Need to fully understand the science and interaction of design parameters 11 of 63
What do we know? Control Air Control Rain Building Enclosure Control Vapor Control heat 12 of 97
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 13 of 63
How do Walls get Wet and Dry? 14 of 63
Building Science: Wetting and Drying How can we keep the sheathing and other materials dry? Don t let them get as wet Create air space to promote drying Design for vapor diffusion drying Keep sheathing warm Safe Storage Capacity Wetting Drying 15 of 63
Water Penetration Control Strategies 16 of 63
Rainscreen Cladding 17 of 63
Rainscreen Cladding - Stucco 18 of 63
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 19 of 63
Air Penetration Control Why? Code requirement Moisture Air holds moisture that can be transported and deposited within assemblies. Energy Unintentional airflow through the building enclosure can account for as much as 50% of the space heat loss/gain in buildings. 20 of 63
Types of Air Barrier Systems Loose Sheet Applied Membrane Taped Joints & Strapping Sealed Gypsum Sheathing Sealant Filler at Joints Liquid Applied Silicone sealants and silicone membrane at Joints Sealed Plywood Sheathing Sealant & Membrane at Joints Sealed Sheathing Membrane at Joints Self-Adhered vapor permeable membrane Plywood sheathing 21 of 63 with taped joints (good tape)
Airtightness Does Not Happen By Accident 22 of 63
How to Tell the Membrane is Not the Air Barrier 23 of 63
Definitely Not An Air Barrier But What Is? 24 of 63
Testing Air Barrier Systems 25 of 63
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 26 of 63
Targets for Walls in Comm/Res Buildings Climate Zone IECC 2015 Above Grade Walls: Min. Eff. R-value Steel Wood 7 15.6 / 19.2 19.6 6 15.6 / 17.5 19.6 5 & 4C 15.6 15.6 4 A/B 15.6 15.6 3 15.6 15.6 2 13.0 / 15.6 15.6 1 13.0 15.6 Based on Maximum Effective Assembly U-value Tables (C402.1.2 (2012), C402.1.4 (2015)) Residential Building R-values buildings similar or in some cases slightly higher 27 of 63
Conductive Heat Loss Control 28 of 63
Conductive Heat Loss Control Insulation between studs is most common heat control strategy Need to consider effective R-values Wood ± R-1 per inch Continuous insulation may be required in some climate zones per IECC 29 of 63
Framing Effect on R-values Overall Effective R-Value ( o F ft 2 hr/btu) 24 22 20 18 16 14 12 10 8 6 Steel 3 5/8 Stud Wood 2x4 Stud Framing @ 16 o.c. Wood 2x6 Stud Steel 2x6 Stud 4 2 0 0 5 10 15 20 25 30 35 40 Framing Factor % 30 of 63
Insulation Placement Consider effective thermal resistance, vapor diffusion profile, and relative durability 31 of 97
The Standard Approach The Old Way Assembly ½ gyp 2x6 @ 16 o.c. R-20 high density insulation ½ sheathing WRB/furring/cladding Standard framing factor 77% cavity, 23% framing U-0.064 R-15.6 32 of 97
Higher R-Values -New Option Option #1 #1 Assembly ½ gyp 2x8 @ 16 o.c. R-30 high density insulation ½ sheathing WRB/furring/cladding Standard framing factor 77% cavity, 23% framing U-0.045 ± R-22.0 33 of 97
Higher R-Values - Option #2 Assembly ½ gyp 2x6 @ 16 o.c. R-21 high density insulation ½ sheathing / WRB 1 insulation (R-4.2 cont.) Furring/cladding Standard framing factor 77% cavity, 23% framing U-0.046 ± R-22 34 of 97
So, What s the Difference? R-22 R-22 35 of 97
Exterior Insulation Selection (Vapor Control) Rigid exterior foam insulations (XPS, EPS, Polyiso, closed cell SPF) are vapor impermeable Rules of thumb: Vapor barrier on warm side Fibrous insulations (mineral fiber / glass fiber) are vapor permeable Allows drying to the exterior Often safer in cold and mixed climates Vapor permeance properties of WRB/air barrier membrane is also very important 36 of 97
Building Science: Wetting and Drying How can we keep the sheathing and other materials dry? Don t let them get as wet Create air space to promote drying Design for vapor diffusion drying Keep sheathing warm Safe Storage Capacity Wetting Drying 37 of 97
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 38 of 63
The Perfect Assembly Rain penetration control: rainscreen cladding over water barrier Air leakage control: robust air barrier system Heat control: continuous insulation layer Locate all barriers exterior of structure Keep structure warm and dry 50+ year old concept! 39 of 97
Wood-Frame Assemblies Perfect Wall 40 of 97
Wood-Frame Assemblies Perfect Roof 41 of 97
Wall-to-Roof Detail 42 of 63
Details Continuity of Control Layers In practice, need to evaluate and design assemblies and details that are not perfect Continuity of control layers within and between assemblies is critical 43 of 63
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 44 of 63
Cross Laminated Timber Ronald McDonald House 45 of 63
CLT Construction Moisture Keep it dry during construction as best as possible 46 of 97
CLT Wall Assemblies 47 of 63
Roof Assembly R-40+ Conventional Roof Assembly 2 ply SBS, 4 Stonewool, 4 Polyiso, Protection board, Tapered EPS (0-8 ), Torch applied Air/Vapor Barrier(Temporary Roof), ¾ Plywood, Ventilated Space (To Indoors), CLT Roof Panel Structure (Intermittent) 48 of 63
CLT Considerations Get the architect to take the final photos 49 of 63
Roadmap BACKGROUND Basics BEST PRACTICES Walls CASE STUDIES CLT Water Low-slope Roofs Air Steepslope Roofs Deep Energy Retrofit Heat 50 of 63
Deep Energy Retrofit Moisture damage at walls and windows Concealed barrier stucco cladding Vented low-slope roof assembly Energy efficient rehabilitation of wall, window, and roof assemblies 51 of 63
5-Storey Wood-frame w/ Exterior Insulation 52 of 63
New Exterior Wall Assembly 53 of 63
New Sloped Roof / Overhang Assembly 54 of 63
New Low-Slope Roof Assembly 55 of 63
Completed Building Enclosure 56 of 63
Summary Control moisture, air, and heat Best practices: Drained & ventilated cladding Keep structure warm and dry: control layers on exterior Less than perfect practices: Analyze and understand wetting / drying balance Provide continuity of control layers within and between assemblies and details 57 of 97
This concludes The American Institute of Architects Continuing Education Systems Course Colin Shane cshane@rdh.com www.rdh.com
Discussion + Questions Colin Shane cshane@rdh.com rdh.com 59 of 63