As insulation and airtightness requirements increase, vapour permeable liquid and self-adhesive air barrier membrane products are rapidly gaining traction in the North American marketplace. This presentation looks at real world testing of various types of these membranes and identifies potential strengths and weakness of these types of products.

1. Vapor Permeable Air Barriers:
Real World Evaluation – What Works, What
Doesn’t and Why
2016 ABAA CONFERENCE & TRADE SHOW
Presented by: LORNE RICKETTS | MASC, EIT
Contributor: GRAHAM FINCH | MASC, P.ENG.
© WWW.RDH.COM - 604-873-1181

2. Outline
 Why We Care About Air Barriers
 Evolution of Air Barrier Systems & Industry Trends
 Evaluation and Comparison of Vapor Permeable
Air Barrier/WRB Membranes

3. Why Airtightness is Important
 Infiltration and Exfiltration Affects:
 Building Energy Consumption – Heat Loss and Gains ($)
 Indoor Air Quality - Pollutants
 Building Durability - Condensation
 Occupant Comfort - Thermal & Acoustics
 >10% of building energy use is due to air leakage12
1. VanBronkhorst, Persily, & Emmerich, 1995
2. Canadian Mortgage and Housing Corporation, 2007

4. Why Airtightness is Important

5.  To control air flow within buildings –
need an Air-Barrier System
 Needed in ALL building types and climate zones
 Is a system of many materials & components which are
interconnected and continuous through the entire building
enclosure – sealed airtight
 Details, ease of installation and material compatibility are
primary design and construction considerations
 Can by placed anywhere within the enclosure*
› Should be protected yet serviceable (if possible)
› With design consideration for the potential for condensation &
convection bypassing stud cavity insulation
› May or may not be combined with vapor & water control functions
› Redundancy is useful
Controlling Air Flow – The Air Barrier System

6. #1: Continuity
 Must be continuous between all
enclosure elements, from above
to below grade, walls to windows
and doors, roof & everything in
between
 Relies on more than one
material
 Compatibility of adjoining
materials critical for long term
sealing
 All trades on project must
understand criticality of air
barrier system & methods for
sealing penetrations
The 5 Requirements for Air Barrier Systems

7. #2: Air Impermeability
 Materials must be resistant to flow
or air at pressures experienced in
the building
 Is a referenced building code
requirement
› Air barrier materials of less than
0.004 cfm/ft2@75 Pa
› Air barrier systems of less than 0.04
cfm/ft2@75 Pa
 Most materials & systems easily
meet requirements
› While important to meet standard a
lower number doesn’t always
translate to better overall building
performance
The 5 Requirements for Air Barrier Systems
Most CMU is not an airtight material by
code definition unless coated
Open & closed cell sprayfoam can be an
air barrier, but gaps, cracks will negate
these numbers by an order of magnitude

8. #3: Durability
 Air Barrier System must be durable
enough to last as long as the
enclosure assembly that it is
installed into (at least 25 to up to
100+ years)
 Must be able to take stresses due
to assembly/material movement,
not be fatigued by cyclical
movement
 Must not degrade due to high or
low temperatures, moisture,
chemicals, contaminants, UV (if
exposed) during construction & in-
service
The 5 Requirements for Air Barrier Systems
Unproven air barrier membrane product
from Europe – failed due to heat aging
effects in roof assembly

9. #4: Strength
 Air Barrier materials must be designed
for the structural wind & resulting
building pressure loads
 Joints and fasteners often critical,
especially for flexible unadhered
membrane systems
› Need for sealing/reinforcing around
sharp fasteners and penetrations
 Adhesion of tapes/sealants critical to
performance & are often the strength
limiting component
The 5 Requirements for Air Barrier Systems

10. #5: Stiffness
 Air Barrier System
must be stiff enough so
that deformations do
not change the air-
permeance and/or
distribute air though
unintentional openings
 One-side supported
sheet membranes
create challenges –
need to support
(rainscreen strapping
works well)
The 5 Requirements for Air Barrier Systems

11. Air Barriers Are Always Systems
AccessoriesMaterials Components
Whole
Building
Airtightness

12. Air Barrier System = As Strong as the Weakest Detail

13. When Airtightness Goes Wrong…

14. Air Barrier System Options

15. Mechanically Attached Air Barrier Membrane
 Loose sheet mechanically attached to wall with cap staples/nails
and sealed with tapes, self-adhered membrane and sealants

16. Rigid Support for Mechanically Attached Air Barriers
During Construction & In-Service

17. Exterior Insulation Sandwich Support for Mechanically
Attached Air Barriers

18. Sealing Mechanical Attached Air Barriers

19. Sealed Sheathing Air Barrier System
 Joints in exterior sheathing (Plywood, OSB, Gypsum) are air-
sealed with sealants, reinforced membrane, strips of self-
adhered membrane, or high-quality tapes

20. Sealed Sheathing Air Barrier System

21. Sealed Sheathing Air Barrier Systems
 Mechanically attached Water Resistive Barrier (WRB) loosely
installed over top of sealed sheathing, but not taped and
detailed as the air barrier

22. Self-Adhered Air Barrier Membranes
 Self-adhered membrane sheets (vapor permeable or
impermeable) applied to sheathing along with tapes/self-
adhered membranes at interfaces

23. Self-Adhered Air Barrier Membranes

24. Liquid/Fluid Applied Air Barrier Systems
 Liquid/Fluid applied membranes (roller, brush or spray)
applied to sheathing with joint/gap fillers or reinforcing

25. Application of Liquid Applied Air Barriers

26. Joints in Liquid Applied Air Barrier Membranes
“band-aid” joints and butt joints Reinforcing tapes, meshes &
membranes

27. Joints in Liquid Applied Air Barrier Membranes

28. Why ALL Joints Get Sealed, Even the Small Ones…
Vapor Permeable Self-Adhesive Sheets
Liquids
Liquids

29. Transitions & Interfaces of Different AB Materials

30. Hybrid Approaches
 Liquid applied membrane window rough openings becoming
common approach with various air barrier approaches – cost
effective & less origami of peel and stick

31.  Air barrier materials should be selected carefully so that when
installed their properties will not negatively affect durability or
assembly drying ability
 Watch vapor permeance of air barrier materials on “cold” side of
insulation in assemblies
 Growing appreciation for vapor permeable products on more
sensitive substrates
Additional Considerations for Air Barrier Systems

32.  Material Compatibility
Additional Considerations for Air Barrier Systems

33. Air Barrier Systems – Material Compatibilities &
Specification Challenges
SBPO
Housewrap
“Special
Silicone”
Below grade
Granulated SBS
membrane
Concrete
Foundation wall
Foil faced
SAM
Silicone
membrane
over plywood
Silicone sealant at
joints and fastener
holes
Foil-faced SBS
Below grade SBS
over Concrete
Foundation
Cement board over
XPS

34. It Is All About the Details

35. Impact of Testing
The Life of a Building
Upstream Effects
Material Selection
Assembly Design
Quality Control

36. Performance & Testing Requirements
 Building codes, energy codes,
and green building programs are
starting to require whole building
airtightness testing for everything from
houses to high-rise
 Washington State & Seattle
 GSA
 US Army Corps of Engineers
 IRC
 IECC
 Passive House
 LEED

37. Impact of Testing
The Life of a Building
Upstream Effects
Material Selection
Assembly Design
Quality Control

38.  Seeing industry shifts from Mechanically Attached to Self-
Adhered Membranes & Liquid Applied Membranes
Trends in Air Barrier Systems

39. Trends in Air Barrier Systems
 Seeing shifts from common bituminous sheet applied
asphaltic peel and stick membranes to non-asphalt
adhesives, and to liquid applied systems (impermeable to
permeable)

40.  Big innovations are being seen in the
wall air barrier system market
 Shift towards “exterior air barrier”
systems on framed walls applied to
exterior gypsum/wood sheathing
 Combined air barrier/water resistive
barrier functions
 Vapor permeable AB/WRB membranes
are growing in popularity due to split
insulation/exterior insulation wall designs
 Fire code (NFPA 285) requirements
driving material choices in some
jurisdictions
Industry Trends & New Air Barrier Systems

41.  Many new cladding
attachment systems &
resulting penetrations for
supports & exterior insulation
 Combined WRB/Air Barrier
behind exterior insulation
 Self-sealing properties
desirable – though can be a
practical challenge
 Current ASTM test standards
have not fully caught up with
real-world applications (huge
range of possible
penetrations)
Industry Trends & New Air Barrier Systems

42. Impact of Testing
The Life of a Building
Upstream Effects
Material Selection
Assembly Design
Quality Control

43. Impact of Testing
The Life of a Building
Downstream Effects
Energy Consumption
Indoor Air Quality
Acoustics
Durability

44. How Well is the Industry Doing – WA State?

45. Buildings are Becoming More Airtight
0.0
1.0
2.0
3.0
4.0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1945 1955 1965 1975 1985 1995 2005 2015
Airtightness[cfm/ft²@75Pa]
Airtightness[L/(s.m²)@75Pa]
Construction of Building [year]
Airtightness Vs Year of Construction of All Buildings
Sample of 179 Buildings
Airtightness versus Year of Construction

46. 2.12
1.12
0.94
0
0.1
0.2
0.3
0.4
0.5
0.0
0.5
1.0
1.5
2.0
2.5
No Requirement, Post 2000
Construction
Washington USACE
Airtightness(cfm/ft²@75Pa)
Airtightness(L/s·m²@75Pa)
Jurisdiction Testing Requirements
Average Airtightness Test Results by Jurisdiction
Performance
Requirement
(2.0 L/ s·m2 @ 75 Pa)
Performance
Requirement
(1.25 L/ s·m2 @ 75 Pa)
(Count 31)
(Count 38) (Count 245)
Testing Requirements are Having an Impact
Airtightness of Buildings – Impact of Requirements
0.4 cfm/ft2 @ 75 Pa
0.25 cfm/ft2 @ 75 Pa

47. How Well Is the Industry Doing – WA State
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
Liquid Applied
(10 Buildings)
Sealed Sheathing
(11 Buildings)
Sheet Applied
(28 Buildings)
Curtain
Wall/Window
Wall/Storefront
(15 Buildings)
Airtightness[cfm/ft²@75Pa]
Airtightness[L/(s·m²)@75Pa]
Leakiest tested
Tightest tested
Median & 1st/3rd
quartile range
WA State Requirement
54 Buildings, Oct 2015 RDH SEA Data
Passive House Range
equivalent ~ 0.6 ACH50

48. Passive House Airtightness – Sealed Sheathing
Orchards & Orenco – Walsh Construction
0.13 ACH @50 Pa, ~0.014 cfm/ft2 @75 Pa

49. Pre-Fabricated Passive House – Self-Adhered Sheet
<0.6 ACH @50 Pa
~0.035 cfm/ft2 @75 Pa

50.  Growing number of options for air-barrier systems, majority
applied at exterior sheathing plane
 Becoming increasingly complicated for designers and
specifiers to select products & ensure compatibility
 Seeing response by manufacturers to move from providing just
materials to whole compatible systems
 Use of vapor permeable liquid and self-adhered sheets
becoming popular choice, especially for more highly insulated
(split insulated) wall assemblies
 Often a go-to option for more air-tight low- to mid-rise wood-
frame buildings
 A lot of options, not all created equal and different pros/cons
of different membranes & systems
Industry Observations

51. Real World Evaluation of Vapor
Permeable Liquid & Sheet Applied Air
Barrier/WRB Membranes

52. Evaluating the Air Barrier/WRB Membrane Market
 From 2013 through 2016 RDH
performed 3rd party critical
evaluation of the most common
vapor permeable air
barrier/WRB membranes
available within the North
American market
 11 liquid applied membranes
 5 self adhered sheet membranes
 14 lab and 14 field tests
performed
 Why? Need for better industry
understanding of AB/WRB
application appropriateness &
missing test standards

53. Why Evaluate?
 Not all products are created equal nor
suitable for all applications
 Key considerations & potential issues
include:
 Longevity, durability, exposure to UV &
heat
 Compatibility & adhesion with other
materials
 Flexibility and gap/crack bridging ability
of field membranes and available joint
treatments
 Curing or adhering in damp, cold or hot
weather
 Important properties changing
negatively with time

54. Key Questions to Answer from the Evaluation
 What designers should consider when selecting various vapor
permeable AB/WRB liquid & sheet membranes for different
wall assemblies and applications?
 What are the real (unpublished) strengths & weaknesses of
different membrane types & chemistries?
 Risk Mitigation
 How does construction exposure impact performance - how long
can membranes be left exposed, what protection is needed?
 Impact of climate and cold, heat, rainwater on substrate and
membranes after application - potential for construction delays
and/or shipping/storage issues?
 Robustness, durability, repairs and re-adhesion

55. What & How to Evaluate
 Series of tests developed to evaluate
selection of 11 liquid applied and 5
self-adhered sheet membranes (all
vapor permeable)
 Membranes selected to represent
cross section of products & chemistries
available on market
 Test procedures designed to be
transferrable across various products
 Real-world applicability prioritized over
standardized testing
 Some ASTM laboratory tests followed
and/or modified
 Developed several new short & long
term field application tests

56. Lab & Field Tests Evaluated
Lab Tests (Incl. ASTM) Field Tests
Cure Time Field Application – Ease of Use
Flexibility Wet-Applied Application
Crack Bridging Wet Cure
Accelerated UV & Heat-Aging Static Gap Bridge
High Temperature Substrate Dynamic Gap Bridge
Short & Long-term Water Immersion Sealant Adhesion Compatibility
Tensile Strength Membrane Compatibility
Elongation Fastener Sealability for Air/Water
Water Ponding Resistance Long Term Mold Growth
Vapor Permeabilty (Wet/Dry Cup) Exterior Weathering – South US
Wet & Dry Substrate Adhesion Exterior Weathering – West Canada
Modified Abrasion Resistance Fire/Torch Resistance
Percentage Solids Re-Adhesion to Aged Substrate

57. Application & Cure Time Test Findings
 Varying material viscosities &
wet-mil thicknesses resulting
in a range of published
application guidelines
 Observed liquid application
difficulty and cure times at
room temperature (72°F) hot
(104°F), cold/frozen (0°F)
substrate conditions
 All products roller applied for
purposes of testing

58. Key Findings – Liquid Applied Cure Time
 Cure time in cold northern climates & potential for freezing a
significant challenge for some membranes
* 48 hour observation means sample did not cure during observed test period

59. Key Findings – Difficulty with Field Application in the
Wintertime
Freezing & ice-lensing in water-based acrylic/latex membranes
Inability to cure (while cold) for some non winter grade silicones/STPEs

60. Gap Bridging Tests
 1st looked at application of liquid
membranes over substrate gaps from
1/16” to 1/4” and ability to “bridge”
gaps without pin-holing as curing
 Key finding – need to detail joints
first with sealant or other joint
treatment for almost all membranes
 2nd looked at application of
membranes over initial gap width and
subjected to dynamic movement of
varying gap widths
 Key finding – None of the tested
liquid membranes can span moving
gaps well – need joint treatments in
all applications

61. Key Findings – Gap Bridging Abilities of Liquids
 Thick or thin – ALL liquid membranes
are very poor at bridging substrate gaps
that either open up in service (sheathing
joints/wood connections etc.) or gaps
which may move in-service due to
substrate shrinkage or building
movement
 Why you must use joint treatments:
sealants, reinforcing meshes, tapes,
membranes etc. at all substrate joints
that could move in-service
 Self-adhered sheets do however
perform well at spanning small gaps &
better for unstable substrates like cross
laminated timber (CLT)

62. Crack Bridging of Liquid & Sheet Membranes?
Vapor Permeable Self-Adhesive Sheets
Liquids
Liquids

63. Impact of Plywood Substrate Checking on Membrane
Performance?
Two thinner (less elastic) membranes applied to plywood which was able to
wet-up & dry numerous times due to full sun/rain exposure after application

64. Impact of UV Exposure & Weathering
 Many membranes do not perform well
when left exposed to UV in the field
for longer than 3-6 months
 Exceptions being silicones and other
products that are formulated to be
more UV stable
 Note: some manufacturers only allow
1-2 months (as evidenced by results
here) which is often too short of
window for installation of claddings
 Many membrane properties are
negatively affected including water
repellency, tensile strength,
elongation, vapor permeance & re-
coating/repair ability

65. Accelerated UV Field Exposure Testing
 Accelerated QUV testing (6 months) is much more severe
than field testing but provided good relative observations that
correlated with field exposure results

66. Re-Adhesion and Repairs to Weathered Samples?
 Tests performed to determine if
membranes could be
re-adhered to themselves in
the event they are left exposed
and damaged by UV & weather
exposure
 Mixed results, though generally
able to re-adhere liquids and
obtain cohesive failures though
some difficulty with degraded
and surface damaged self-
adhered sheets

67. Elongation Properties – Before & After Aging
-400%
-350%
-300%
-250%
-200%
-150%
-100%
-50%
0%
50%
100%
0
50
100
150
200
250
300
350
400
450
500
Silicone Silicone STPE Latex Acrylic
Polymer
STPU Acrylic
Polymer
Silicone Latex Acrylic
Polymer
3 Ply PP 3 Ply PP 3 Ply PE 3 Ply PE
%Change
Elongation(%)
Change in Elongation
Unweathered Weathered %Change

68. Tensile Properties – Before & After Aging
-300%
-250%
-200%
-150%
-100%
-50%
0%
50%
100%
150%
0
2
4
6
8
10
12
14
Silicone Silicone STPE Latex Acrylic
Polymer
STPU Acrylic
Polymer
Silicone Latex Acrylic
Polymer
3 Ply PP 3 Ply PP 3 Ply PE 3 Ply PE
%Change
UltimateTensileStrength(MPa)
Change in Tensile Strength
Unweathered Weathered %Change

69. Key Findings: Lab & Field Mold Growth Testing
 Be wary of ASTM “mold-
resistant” claims
 Under favorable warm & humid
conditions and a few months of
time mold will growth on the
surface of most liquid
membranes

70. Membrane Construction Robustness
 Varying Degrees of Surface Toughness & Abrasion Resistance
 Tougher acrylic & latex membranes performed well - silicone, STPe
and STPu membranes all similarly soft and easily damaged

71. Impact of Prolonged Wetting & Immersion
 Some membrane properties degrade when exposed to
prolonged wetting (swelling, reversion, fungal growth)

72. Water Ponding Resistance – Short & Long Term
 Modified ASTM Hydrostatic
pressure testing performed to
evaluate water ponding resistance
(i.e. horizontal surfaces including
window sills, parapets etc.)
 Observations at 1, 2, and 48 hours
and 1 week
0 1 2 3 4
Examples of Evaluation Scale Results

73. Results – Liquid Applied 1/2
0=None, 1=Very low, 2=Low, 3=Moderate, 4=High
Observations
Sample ID Pre-test 1hour 2 hours 48 hours 1 week Measure
(0-4)1
SEC 2500
(L01)
1
SEC 2600
(L02)
1
R-Guard
Cat5 (L03)
0
Barritech VP
(L04)
3
ExoAir 230
(L05)
2
XL-Perm Air
VP (L06)
3
Silicone
Silicone
STPe
Latex
Acrylic
Polymer

74. Results – Liquid Applied 2/2
0=None, 1=Very low, 2=Low, 3=Moderate, 4=High
Observations
Sample ID Pre-test 1hour 2 hours 48 hours 1 week Measure
(0-4)1
SEC 2500
(L01)
1
SEC 2600
(L02)
1
R-Guard
Cat5 (L03)
0
Barritech VP
(L04)
3
ExoAir 230
(L05)
2
XL-Perm Air
VP (L06)
3
ExoAir 230
(L05)
2
XL-Perm Air
VP (L06)
3
Air-Bloc
33MR (L07)
2
DefendAir
200 (L08)
3
EmeraldCoat
(L09)
3
Enershield
HP (L10)
0
Liquid Tyvek
(L11)
4
STPU
Acrylic
Polymer
Silicone
Latex
Acrylic
Polymer
STPe

75. Results – Self-Adhered Sheets
0=None, 1=Very low, 2=Low, 3=Moderate, 4=High
Enershield
HP (L10)
0
Liquid
Tyvek
(L11)
4
WrapShield
SA (S01)
4
SopraSeal
Stick VP
(S02)
Apparatus
failure
Perm-A-
Barrier VPS
(S03)
3
Blueskin
VP 160
(S04)
4
Observations
Sample ID Pre-test 1hour 2 hours 48 hours 1 week Measure
(0-4)1
SEC 2500
(L01)
1
SEC 2600
(L02)
1
R-Guard
Cat5 (L03)
0
Barritech VP
(L04)
3
ExoAir 230
(L05)
2
XL-Perm Air
VP (L06)
3
3 ply
PP
3 ply
PP
3 ply
PE
3 ply
PE

76. Water Ponding Resistance
 Most membranes fail ponding test after 1-2 hours (usually
“just after” the ASTM test timeline)
 Self-adhered sheet applied membranes generally less water
resistant than liquid applied membranes in this application
 Slight relationship between water transport and vapor
permeance of the sample membranes, but not always
 No relationship between water transport membrane and
thickness
 Generalized differences between chemistry, though not
always consistent
 Key Message – difficult to determine acceptable water
resistance for some applications from standard testing &
numerical water column tests

77. Ongoing Research – Use of Vapor Permeable Liquids
on Wood-frame Window Sills?
Can this horizontal membrane be vapor
permeable like the jambs & head?

78. Are Vapor Permeable Liquids Safe for Use on Wood-
frame Window Sills?
0
5
10
15
20
25
30
35
40
45
0 Days 7 Days 14 Days 21 Days 28 Days
MoistureContent(%)
Plywood Edge - At Center
L01 BASF MaxFlash L02 Prosoco R·Guard FastFlash
L03 DowCorning 778 Liquid Flashing L04 DuPont Tyvek Fluid Applied Flashing
L05 GE Momentive SCS2000 SilPruf* L06 Protectowrap LWM200
Safe MC <20%
not safe with these liquids
safe with these liquids
maybe okay with these liquids
Moisture Content of Edge of Plywood at Window Sill

79. Impact of the Wrong Liquid Applied Vapor Permeable
on a Wood Window Sill
Mold after 30 days due to absorption into OSB sheathing below a relatively
absorptive & permeable liquid applied window sill flashing

80. Wet Weather Challenges with Liquid Membranes

81. Comparative Rainwater Exposure Testing
Membranes after 1 hour of simulated rain water exposure (1.4 mm/minute)
Acrylic
Polymer STPe
Silicone
Latex
Acrylic Polymer
Silicone
Acrylic Polymer
Silicone
Latex
STPu
STPe

82. Adhesion to Dry & Damp Wood Substrates
 Membranes applied separately to
dry and wet plywood samples
and allowed to cure for >1 month
(plywood allowed to dry) before
pulling

83. Adhesion to Dry & Damp Wood
C
C
A
C
A C
C
C
A
A
A A C
A
A A
A
C A C
C
A
A
C
A
C A
0
0.5
1
1.5
2
2.5
MembraneAdhesiveStrength-MPa
Adhesive Strength of Membrane - Dry & Damp Plywood Substrate
Dry Plywood
Damp Plywood
A

84. Sealant Adhesion & Material Compatibility
 Applied 28 different common construction
sealants (of all chemistries) to the 16
different membrane substrates
 Sealant beads pulled in triplicate to record
the peel force and failure mechanism
(adhesive/cohesive)
 Wide range of results
 Sealants generally more compatible with
liquid applied membranes than self-adhered
sheets
 Stick with similar chemistries where possible
 Key conclusion – always test
compatibility prior to specifications

85. Material Compatibility with Construction Tapes & Peel
and Stick Membranes
 Very difficult to stick some tapes/membranes to several of the
membranes – need for compatible systems & solutions for
enclosure interfaces (i.e. roofing, below grade etc.)

86. Membrane Self-Sealing Abilities
Self-taping metal screw for
cladding attachment support
Fuel-cell actuated nail type
insulation retaining fastener

87. Membrane Self-Sealing Abilities?
 ALL liquid and self-adhered
sheet membranes (even 45
mil SAM) will leak with the
right amount of water and
air pressure through screw
fasteners
 Missing a stud with a self-
tapping screw or stripping a
fastener almost guarantees
a leak
 Further research is needed
to develop realistic fastener
self-sealing testing
procedures for WRBs

88. Liquid & Sheet Membranes & Self-Tapping Screws
3 ply polypropylene sheet, fibers
damaged with screw threads & no
longer self-sealing
Thin elastomeric liquid membrane chewed
up by screw threads & no longer self-
sealing
Thick liquid membrane chewed up by screw
threads & no longer self-sealing
Thick elastomeric liquid membrane
chewed up by screw threads & no longer
self-sealing

89. Flammability
 Testing the “what-if” scenario
when the roofing torch comes
into contact with these
membranes at tie-ins etc.
 Several of the membranes
were quite resistant to flame
whereas some were found to
be quite combustible (STPu
and few other chemistries) to
support propagation of flame
(even ones that claimed
acceptance with NFPA 285)

90. Evaluation Criteria & Summary
 Long-term water resiliency
 Water Absorption Test, Water Ponding Resistance Test, and Long Term
Mold Resistance Test.
 Ease of application
 Cure Time Test, Wet Applied Field Run Test, Application Difficulty Test,
Re-Adhesion Test, Wet Cure Test, and Static Gap Bridge Test.
 Compatibility with other materials
 Sealant Adhesion Test, Peel and Stick Membrane Compatibility Test,
Fastener Self-Sealability Test.
 Construction Robustness
 Flexibility Test, Crack Bridging Test, High temperature Test, Pull
adhesion (dry and wet) test, Modified abrasion resistance test, and
Dynamic gap bridge test
 Longevity
 Accelerated UV & Heat Age Test, Tensile Strength and Elongation Test,
and Exterior Weathering Test

91. Conclusions
 Found advantages and disadvantages of each membrane –
no clear winner across all categories
 Top 5 scored between 6.6 and 7.0 out of 10.0 in evaluation scale
(All liquids and 3 different chemistries)
 Lowest 5 score between 4.3 and 5.8 out of 10 (3 of 5 were self-
adhered sheets)
 With highest score being 70%, improvement could be made to all
(and will be in time)
› Already seen “winter-grade” membranes being introduced in
past year to respond to cold weather issues
 Thick vs Thin membrane marketing – no correlation to useful
real world performance (incidentally top 3 performers were all
thinner membranes)

92. Conclusions
 Most useful to look at each membrane in context of assembly
and desired performance requirements
 Watch length of construction exposure
 Check compatibility of all interfacing materials
(good specs)
 Consider where being used (behind exterior insulation? open
rainscreen cavities? horizontal surfaces?)
 Don’t be swayed by marketing literature & claims and don’t
assume current ASTM test standards cover all situations or real-
world applications
 Many of these 28 tests can be easily replicated yourself – best
done comparatively instead of looking at absolute performance
values
 No one size fits all solution!

93. How it Might Impact ABAA
 Opportunity for an organization like ABAA help raise the bar
for AB/WRB membranes and set reasonable & useful
standards for evaluation

94.  rdh.com
Questions + Discussion