Post on 24-Sep-2018
THE EFFECT OF REFLECTIVE ROOF COATINGS ON THE
DURABILITY OF ROOF SYSTEMS
Joseph W. Mellott II and Donald C. PortfolioROOF COATING MANUFACTURERS ASSOCIATION
International Roofing Expo
TU-03 Technical
March 6, 2007
Las Vegas, NV
AIA CREDITS
Hanley Wood is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members available on request.
AIA CREDITS
This program is registered with the 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.
LEARNING OBJECTIVES
Recognize the effect of reflective roofing on aging of roofing membranesIdentify the differences in reflectance of various reflective materialsDistinguish the resultant differences in natural weathering at three different US locationsIdentify physical properties of asphalt and roofing membranes to help understand measurable aging properties of the membrane (substrate)
BACKGROUND
1997 Roof Coating Manufacturers (RCMA) Association Technical Committee– Research program with Oak Ridge National
Laboratory (ORNL)– Heat Transfer through roofing systems related to
reflectance and emittance of systemUn-CoatedAluminum Roof CoatingsWhite Elastomeric Roof Coatings
COATINGS TESTED
Aluminum Roof Coating (Non-Fibrated)Aluminum Roof Coating (Fibrated – Good)Aluminum Roof Coating (Fibrated – Medium)Aluminum Roof Coating (Fibrated – Economy)White Elastomeric Coating (Acrylic)White Elastomeric Coating (Styrene-Acrylic)
COATING FORUMLATIONS
Aluminum Roof Coatings– Generic Formulations (Group Agreement)
White Elastomeric– Starting Formulations from 3
manufacturers of latex used in the coatings– Two types
AcrylicStyrene Acrylic
ROOFING MEMBRANE
4 – Ply Glass Built-Up Roofing MembraneSurfacing– Aluminum Coating (NF): 1 gal/sq in 2 coats– Aluminum Coating (F): 1.5 – 2 gal/sq in two
coats– White Elastomeric: 1.5 gal/sq in 2 coats– Nothing
SCOPE OF PROJECT
Original Primary (ORNL)– Effect of reflectance and emittance on heat
transfer through roofing membrane– Effect of weathering on reflectance and
emittance over three yearsSecondary (RCMA)– Effect of reflectance properties of the BUR
membrane system over time
RESULTS ASPHALT PROPERTIES
Coating Type
Ref. Initial
Ref. 3 Yr
SP. °F 3 Yr
Δ SP, °F
Pen, dmm3 Yr
Δ Pen, dmm
White SA 0.86 0.52 109 5 8 4
Al-F Med 0.64 0.34 118 14 6 6
Al-NF 0.71 0.39 124 20 4 7
None 0.06 0.06 131 27 4 7
ASPHALT PROPERTIES
Both increase in softening point and decrease in penetration are measures of asphalt aging
CONCLUSIONSReflective coatings result in a measurable effect on the change of asphalt properties measuredReflective coatings result in a smaller increase in softening point and decrease in penetration than a non-reflective surface
CONCLUSIONSThe asphalt properties measured are associated with the aging of asphaltReflective coatings decrease the rate at which asphalt ages in a BUR systemThere is need for more work due to inadequate design of original work
WHY THE INTEREST IN MEMBRANE PROPERTIES?It Can Be Difficult to Justify Cool Roofing Just in Terms of Energy SavingsInsulation Can Be a Better Energy Savings Choice than a White Coating –Insulation Does Not Have to be Cleaned Periodically and Does Not Have to be Replaced (Re-coated) Periodically
WHY THE INTEREST IN MEMBRANE PROPERTIES?Insulation Causes Higher Temperatures in the Membrane Than No InsulationA White “Cool” Coating Applied to an Insulated or Non-Insulated Roofing System Can Reduce the Temperature of the Membrane
RCMA: The Next Step
Based on the data generated in the preliminary study at Oakridge National Laboratories, The RCMA launched a new study in 2003.
Coating Durability Membrane Performance
Multi-year Project to Determine the Effect of Roof Coatings on Membrane Performance and Weathering Performance of
Coatings
Selection of Coatings
How Were the Coatings Selected?
3 manufacturers of each type selected at random3 manufacturers submitted blind samples1 of the samples chosen for the study
The Substrates
BUR– 2 Plies of Type IV Glass and 1 G2 Base in Type IV
Asphalt
SBS– G2 Base, SBS Cap in Type IV Asphalt
APP– G2 Base, APP Smooth – Torched
EPDM– 45 mil (Black)
Insulation/Deck– ½ Plywood, 2” Iso + ½” Cover board
Deck Design
2 square feet per section8 separate sectionsBuilt for Testing Not as RoofingAllows for 4 separate testsSmall Initial Deck produced for Initial Test
Location of Decks
Northeast OhioWarm, Cold, Wet, Dry
South FloridaHot, Wet
ArizonaHot, Dry
Testing Protocol for BUR, SBS and APP Decks
Tensile / ElongationReflectanceSoftening PointPenetrationIatroscanDSR
Testing Protocol for EPDM Deck
Tensile / ElongationReflectanceCold Bend Thickness
Coating PerformanceSEBS Solvent Based White Elastomeric Coating
20
30
40
50
60
70
80
90
SBS APP EPDM BUR
Ref
lect
ance
Original on Substrate NEO 6 months on Substrate NEO 10 months on Substrate NEO 17 months on Substrate NEO22 months on Substrate NEO 30 months on Substrate NEO 37 months on Substrate in NEO Original on Substrate FLA5 months on Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Coating PerformanceAcrylic White Elastomeric Coating
20
30
40
50
60
70
80
90
SBS APP EPDM BUR
Roofing System Type
Ref
lect
ance
Original on Substrate NEO 6 months on Substrate NEO 10 months on Substrate NEO 17 months on Substrate NEO22 months on Substrate NEO 30 months on Substrate NEO 37 mos. on Substrate in NEO Original on Substrate FLA5 months on Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Coating PerformanceStyrene Acrylic White Elastomeric Coating
20
30
40
50
60
70
80
90
SBS APP EPDM BUR
Roof System Type
Ref
lect
ance
Original on Substrate NEO 6 months on Substrate NEO 10 months on Substrate NEO 17 months on Substrate NEO22 months on Subtrate NEO 30 months on Substrate NEO 37 months on Substrate in NEO Original on Substrate FLA5 months of Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Coating PerformanceHigh Softening Point Asphalt Aluminum Coating
20
30
40
50
60
70
80
90
SBS APP EPDM BUR
Roofing System Type
Ref
lect
ance
Original on Substrate NEO 1 Year on Substrate NEO 16 months on Substrate NEO 23 months on Substrate NEO28 months on Substrate NEO 36 months on Substrate NEO 43 months on Substrate in NEO Original on Substrate FLA5 months on Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Coating PerformanceLow Softening Point Asphalt Aluminum Coating
20
30
40
50
60
70
80
90
SBS APP EPDM BUR
Roofing System Type
Ref
lect
ance
Original on Substrate NEO 1 Year on Substrate NEO 16 months on Substrate NEO 23 months on Substrate NEO28 months on Substrate NEO 36 months on Substrate NEO 43 months on Substrate in NEO Original on Substrate FLA5 months on Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Coating PerformanceWater Based Asphalt Aluminum Coating
20
30
40
50
60
70
80
90
SBS APP EPDM BUR
Roofing System Type
Ref
lect
ance
Original on Substrate NEO 1 Year on Substrate NEO 16 months on Substrate NEO 23 months on Substrate NEO28 months on Substrate NEO 36 months on Substrate NEO 43 months on Substrate in NEO Original on Substrate FLA5 months on Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Coating PerformanceAsphalt Emulsion
0
2
4
6
8
10
12
14
16
18
20
SBS APP EPDM BUR
Roofing System Type
Ref
lect
ance
Original on Substrate NEO 1 Year on Substrate NEO 16 months on Substrate NEO 23 months on Substrate NEO28 months on Substrate NEO 36 months on Substrate NEO 43 months on Substrate in NEO Original on Substrate FLA5 months on Substrate FLA 9 months on Substrate FLA 16 months on Substrate in FLA
Membrane Initial PropertiesProperty ResultsMembrane Identification APP SBS BURSoftening Point, °F 306 249 231Penetration, dmm 16 22 10Tensile Strength, Peak Load, MD, lbf. 123 123 271Elongation, at Peak Load, MD, % 51 34 3.2
Iatroscan Composition
Saturates, % 16.2 13.9 TBDAromatics, % 39.7 24.2 TBDResins, % 36.5 52.7 TBDAsphaltenes, % 7.6 9.2 TBD
DSR TBD TBD TBD
Membrane Initial Properties
Property Results
Membrane Identification EPDM
Thickness, in. 0.435
Tensile Strength, psi 1389
Ultimate Elongation, % 893
Tear Resistance, lbf. 10
DECKS – TAMPA, FL 2005
SBS
EPDMBURAPP
DECKS IN FLORIDA
APP
AcrylicStyrene Acrylic
High SP ALLow SP AL
Water Based AL
Asphalt Emulsion
SEBS
DECKS IN FLORIDA
SBS
DECKS IN FLORIDA
BUR
DECKS IN FLORIDA
EPDM
TYPICAL DIFFERENCES
Styrene-Acrylic Acrylic
TYPICAL DIFFERENCES
WB Low SP High SP
DECKS IN NE OHIO 11-06
SEBS Acrylic
Sty. Acrylic
High SP Al
Low SP Al
Al Emulsion
Asphalt Emulsion
APP
DECKS IN NE OHIO 11-06
BUR
DECKS IN NE OHIO 11-06
EPDM
DECKS IN NE OHIO 11-06
SBS
DECKS IN FLORIDA – 12/2006
Acrylic
Styrene AcrylicHigh SP AL
Low SP ALWater Based ALAsphalt Emulsion
SEBS
APP
DECKS IN FLORIDA – 12/2006
SBS
DECKS IN FLORIDA – 12/2006
BUR
DECKS IN FLORIDA – 12/2006
EPDM
INTERIM RESULTSOUTDOOR WEATHERING
Styrene Acrylic Coating is Performing Significantly Better than Acrylic CoatingLow Softening Point Aluminum Coating is Performing Slightly Better Than High Softening Point Aluminum and Water Based AluminumPerformance of Roof Coatings does not appear to be very Substrate Dependent in the long term
CONCLUSIONS – PART II
Expected Four Years After Initial Membrane SamplingInterim Reflectance Measurements Will Be Determined at Approximate Six Month Intervals
ACKNOWLEDGEMENTS
Deck Construction– Momentum Technologies– SR Roofing Products
Outdoor Weathering and Testing– Henry Company– Momentum Technologies– PRI Asphalt Technologies
THANK YOU
This concludes the American Institute of Architects Continuing Education Systems Program.
QUESTIONS?
Donald C. Portfolio: PRI Construction Materials Technologies, Tampa, FL
Joseph W. Mellott II: The Garland Company, Cleveland, OH