This document provides an overview and agenda for an Energy Trust of Oregon envelope design training event held on October 2015. The training covered key topics related to building enclosure design including critical barriers like the thermal barrier, air barrier and vapor barrier. It discussed approaches to designing continuous barriers and managing issues like thermal bridging. Insulation strategies like interior, exterior and split insulation were also reviewed. The document aimed to educate designers on best practices for creating efficient, durable and low energy building enclosures.
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Energy Trust New Buildings Envelope Design Training
1. Energy Trust New Buildings
Envelope Design Training
October 27th, 2015
2. About
• Independent nonprofit
• Serving 1.5 million
customers of
Portland General
Electric, Pacific Power,
NW Natural and
Cascade Natural Gas
• Providing access to
affordable energy
• Generating
homegrown, renewable
power
• Building a stronger
Oregon and
SW Washington
4. 4
Projects served:
• New construction
• Major renovation
• Tenant build-out
• Additions or
expansions
5. Trainings and Events
• Allies for Efficiency Training Series
• Building Energy Simulation Forum
• Allies for Efficiency 2.0 (tentative title)
Priority Registration for New Buildings Allies!
7. Energy Trust of Oregon
Envelope Design
Training
AIA Portland
October 2015
Marty Houston,
AIA, CSI, LEED AP
Walsh Construction Co.
8. Enclosure Design Training
• The Role of the Building Enclosure in the
Creation of Low Energy Buildings…
• Critical Barriers
• The Thermal Barrier
• The Air Barrier
8
11. Definition:
Water Vapor Diffusion
The process by which water vapor spreads or
moves through permeable materials caused
by a difference in water vapor pressure.
11
13. Definition:
Vapor Permeability
Permeability, rated in Perms, is a measure of
the rate of transfer of water vapor through a
material.
The higher the number, the easier it is to pass
water vapor through a material.
13
17. Definition:
Dew Point
• The dew point is the temperature to which a
given parcel of air must be cooled, at
constant barometric pressure, for water vapor
to condense into water.
17
20. 20
Pop Quiz
1. How many of you know the difference
between an air barrier, a weather resistive
barrier and a vapor barrier?
2. How many materials do you need to have all
three in one wall?
23. The Path to Low Energy Buildings
1
2
3
4
23
Basic Building
Design
Enclosure
MEP
On-site Renewable
Energy
24. The Path to Low Energy Buildings
1
2
3
4
24
Basic Building
Design
Enclosure
MEP
On-site Renewable
Energy
Load Reduction
25. The Path to Low Energy Buildings
1
2
3
4
25
Basic Building
Design
Enclosure
MEP
On-site Renewable
Energy
Load Reduction
Meeting loads as
efficiently and cleanly
as possible…
26. The Path to Low Energy Buildings
1
2
3
4
26
Basic Building
Design
Enclosure
MEP
On-site Renewable
Energy
Load Reduction
28. Basic Building Design (BBD)
28
• Low energy building design should focus first
on a few basic building design concepts:
– Building size & shape
• As small as possible for the given program
• As compact as possible for the given program, relative to
climaticfactors
– Building orientation
– Optimized glazing design
33. BBD
• Optimized Glazing Design – i.e. windows
sized, configured and oriented to optimize
daylighting, views and solar gain
– Window-to-wall ratio managed to avoid excessive
heat loss while allowing for daylighting and views
– Glazing systems designed to avoid excessive solar
gain – i.e. glass coatings, shadings, etc.
– Use well-insulated & airtight glazing systems
33
36. Critical Barriers
• Water-Shedding Surface Rain Penetration Control
• Water-Resistive Barrier Rain Penetration Control
• Thermal Barrier Thermal Control
• Air Barrier Air Leakage Control
• Vapor Barrier Vapor Diffusion Control
36
37. Critical Barriers
• Water-Shedding Surface Rain Penetration Control
• Water-Resistive Barrier Rain Penetration Control
• Thermal Barrier Thermal Control
– Controls conductive and radiant heat flow
• Air Barrier Air Leakage Control
– Controls air flow / convective heat flow
• Vapor Barrier Vapor Diffusion Control
37
38. Critical Barriers
Thermal Barrier
Exterior
Stucco Cladding
Air Space
Sheathing Paper
Exterior Sheathing
Insulated Stud Space
Polyethylene Sheet
Interior Gypsum Board
Interior
Critical Barriers:
Vapor Barrier
Air Barrier
Water Resistive Barrier
Water Shedding Surface
Exterior Interior
39. Continuity – A Key Principle
• Continuous barriers are required to achieve
effective thermal and moisture control
• Continuity of critical barriers must be
provided, not just at field areas, but also at
interface details
– Transitions
– Penetrations
– Terminations
39
40. Continuity – A Key Principle
• Lack of continuity at critical barriers may lead to:
– Water leakage
– Air leakage
– Thermal bridging
– Condensation
• Resulting in:
– Poor energy performance
– Durability problems
40
41. Design of Critical Barriers
• Designer of the building enclosure should be
able to trace the continuity of each critical
barrier through the enclosure system
• Begin with building sections / wall sections
• Continue with foundation, wall and roof details
• Establish lines of continuity of all five barriers
41
48. RDH
Window: Aluminum Rebate (Box) Frame
Wall Assembly: Non Combustible - Exterior Insulation
Cladding: Brick Veneer
WINDOW SILL – JAMB
Steel Stud Framing
Dens-Glass Wall Sheathing
Beveled Wood Sub-Sill
Self Adhered Membrane
Metal Angle
Sill Membrane
Corner Membrane
Jamb Membrane
Shims
Sealant
Self Adhered Membrane
Interior Gypsum Board
Wood Stool
Exterior Rigid Insulation
Brick Veneer and Ties
Metal Drip Edge
Backer Rod & Exterior Sealant
Backer Rod & Interior Sealant at jamb
Window
VAPOUR BARRIERVAPOUR BARRIER
AIR BARRIERAIR BARRIER
EXT. MOISTURE BARRIER
VAPOUR BARRIER
AIR BARRIER
WATER SHEDDING SURFACE
EXT. MOISTURE BARRIER
VAPOUR BARRIER
END
48
Source:
RDH Building Sciences
THERMAL BARRIER
49. Durability - A Key Principle
• Durable = sustainable
• Selection and use of durable materials - suited
to the application / exposure - is critical
• Effective design and detailing of the enclosure
for watertightness, airtightness and thermal
resistance is essential for achieving both
energy performance and long term durability
49
50. The Air Barrier
• The air barrier is the system of materials that
controls air leakage / convective heat flow
through the building enclosure
• The air barrier is not one material but instead
is an integrated system of many different
materials/components
50
51. The Problem of Air Leakage
• Air leakage accounts for 20-40% of the heat
loss through building enclosures…
• Air leakage = higher energy costs
• Air leakage = larger carbon footprint
• Air leakage = reduced water penetration control
• Air leakage = increased condensation risk
• Air leakage = poor airflow control
– Impacts reliability of ventilation system design
51
52. 52
Source: State of Wisconsin Minimium Requirements for the Building Envelope
53. Air Barrier - Definitions
• Air barriers are defined by their air permeance
• Air Barrier Association of America (ABAA) has
taken lead position in developing and
promulgating standards
• Now incorporated in many codes - including
WSEC
• “Materials”
– ≤ 0.04 cfm/sf @ 1.57 psf pressure differential
– ASTM E 2178, Standard Test Method for Air
Permeance of Building Materials
53
54. Air Barrier - Definitions
• “Assemblies”
– A collection of air barrier materials and air barrier
components assembled together in a specific
manner to create continuity (ABAA)
– ≤ 0.04 cfm/sf @ 1.57 psf
– ASTM E 2357, Standard Test Method for
Determining Air Leakage of Air Barrier Assemblies
54
55. Air Barrier - Definitions
• “System”
– An air barrier system is a system of building
assemblies within the building enclosure designed,
installed, and integrated in such a manner as to stop
the uncontrolled flow of air into and out of the building
enclosure (ABAA)
– A whole building air barrier is a system
– ≤ 0.40 cfm/sf @ 1.57 psf
– ASTM E 779, Standard Test Method for Determining
Air Leakage Rates by Fan Pressurization
– Alternate standard: ≤ 0.25 cfm/sf @ 1.57 psf (USACE)
55
58. Air Barrier - Materials
• Material selection criteria includes:
– Air permeance
– Vapor permeance
– Water resistance (if serving as WRB also)
– Cost
– Constructability
– Availability
• Location / placement of air barrier relative to
insulation location is major determinant
58
59. Air Barrier - Approaches
• Interior Side
– Airtight Drywall Approach
– Sealed Polyethylene Approach
• Exterior Side
– Exterior Sheathing Approach
– Sheathing Membrane Approach (“housewrap”)
• Where cavity insulation approach is used
• Vapor permeable
59
60.
61.
62. Air Barrier - Approaches
• Exterior Side
– Exterior Sheathing Approach
– Sheathing Membrane Approach (“housewrap”)
• Where cavity insulation approach is used
• Vapor permeable
– Sheathing Membrane Approach (“peel & stick”)
• Where exterior insulation approach is used
• Vapor impermeable
62
63.
64. Air Barrier - Approaches
• Exterior Side
– Exterior Sheathing Approach
– Sheathing Membrane Approach (“housewrap”)
• Where cavity insulation approach is used
• Vapor permeable
– Sheathing Membrane Approach (“peel & stick”)
• Where exterior insulation approach is used
• Vapor impermeable
– Sheathing Membrane Approach (fluid-applied)
• Vapor permeabilitydependent on whether cavity
insulation or exterior insulation approach is used
64
65.
66. Air Barrier - Continuity
• To design and construct a complete air
barrier system for the building, continuity
must be provided at interfaces between all
materials and components…
• Easier said than done!
66
67. Air Barrier - Continuity
• Key Details for Air Barrier Continuity:
– Wall to foundation
– Roof to wall
– Floor lines
– Window and door perimeters
– Other penetrations
– Transitions between wall types
– Transitions between cladding materials
67
69. Airtightness & IAQ
• Mechanical ventilation becomes increasingly
important as building airtightness increases
• Effectiveness - and efficiency - of ventilation
system becomes more highly critical to
ensuring overall building performance,
including indoor air quality…
– Dedicated fresh air delivery to each space
– Controlled air flow between spaces
– Controlled ventilation rates
– Heat recovery from exhaust air
– IF YOU BUILD IT TIGHT- VENTILATE RIGHT! 69
71. The Thermal Barrier
• The thermal barrier is the system of materials
that controls conductive and radiant heat flow
through the building enclosure
• Insulation - yes - but many other materials
and components serve as part of the thermal
barrier
71
86. Other Thermal Bridges
• Window Frames (Aluminum & Steel)
• Metal Subframing at Cladding Systems
• Steel Ledger Angles at Cladding Systems
• Projecting Slab Edges (Concrete)
• Large Structural Framing Members (Steel)
86
96. Condensation Risk
• Thermal bridges not only cause problems
with poor thermal performance but can also
lead to significantly increased risk of
condensation problems
96
105. INSULATION STRATEGIES
Interior Insulation(wall)
• Advantages
• easier to install
• Materialcosts low
• Disadvantages
• Allows dewpoint interior to weather barrier
• May requirefire separationfrom habitable space
• Does not protect weather barrier from thermal
movements
• Thermal bridgingat framing members reduces
effectiveR-value
106. INSULATION STRATEGIES
Interior Insulation (wall)
• Product Types
• Fiberglass batts (3.1 to 4.3/in)
• Mineral wool (3.7 to 4.5/in)
• Cotton batts (3.5/in)
• Sprayed-in cellulose (3.6 to 3.8/in)
• Sprayed-in fiberglass (3.7 to 4.2/in)
• Closed cell spray foam (6/in)
• Open cell spray foam (3.5/in)
107. INSULATION STRATEGIES
Exterior Insulation (wall)
• Advantages
• Mitigates thermal bridging
• Protects weather barrier from thermal movements
• Pushes dewpoint exterior of weather barrier
• Disadvantages
• Installation requires more coordination
• Higher material cost
• Drying time of wall may lengthen depending on
material choices
108. INSULATION STRATEGIES
Exterior Insulation (wall)
• Product Types
• Extruded polystyrene (XPS) (4.5 to 5.0/in)
• Expanded polystyrene (EPS) (3.6 to 4.0/in)
• Polyisocyanurate (5.6/in)
• Closed cell spray foam (6/in)
• Mineral wool (3.7 to 4.5/in)
109. INSULATION STRATEGIES
Split Insulation(wall)
• Advantages
• Mitigatesthermal bridging
• Protects weather barrier from most thermal
movements
• Sometimes cost effective
• Disadvantages
• Installationstill requires more coordination
• Drying time of wall may lengthendepending on
materialchoices
• Weather barrier materialchoices narrow
• Dewpoint will reside in stud cavity….but for how long?
110. INSULATION STRATEGIES
Interior Insulation(roof)
• Advantages
• Easier to install
• Materialcosts low
• Disadvantages
• Allows dewpoint interior to roof membrane
• Does not protect roof membrane from thermal
movements and weathering
• Susceptible to moistureduring construction
• Thermal bridgingat fasteners reduces effectiveR-
value mildly
111. INSULATION STRATEGIES
Infrared Scan of EPDM Roof
THERM model w/ fasteners
thru all insulation
THERM model w/ fasteners thru
first layer of insulation
112. INSULATION STRATEGIES
Exterior Insulation (roof)
• Advantages
• Mitigates thermal bridging
• Protects roof membrane from thermal movements
• Pushes dewpoint exterior of roof membrane
• Quicker “dry-in” of building
• Disadvantages
• Installation requires more coordination
• Insulation needs to be covered (pavers, ballast,
vegetation, etc.) to protect from exposure
171. Energy Trust of Oregon
The Quality Process-
You Don’t Get
Something for Nothing
AIA Portland
October 2015
Marty Houston,
AIA, CSI, LEED AP
Walsh Construction Co.
181. “Cost of Quality Versus Cost of Non-
Quality in Construction: the Crucial
Balance”
Yehiel Rosenfeld
Published November 2008
181
182. Key Ideas and Definitions
• All Buildings are Prototypes
• ISO9000: Quality is a Managerial Issue
• Focus on Proactive Measures
• Internal Failures
• External Failures
• Total Cost of Quality
182
191. Total Costs of Quality
• Prevention
• Appraisal
• Internal Failures
• External Failures
191
192. Hidden Costs of Non- Quality
• Exposure to Future Liabilities
• Failure to Retain Existing Customers (tenants)
• Loss of New Customers (tenants)
• Short and Long-Term Damage to Reputation
• Increased Insurance Costs
192