EPDM Membrane Roofing
EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber roofing membrane widely used for commercial and low-slope applications. Known for its exceptional weathering characteristics, flexibility in cold temperatures, and long-term durability, EPDM has been a staple in the commercial roofing industry for over 50 years, providing reliable waterproofing performance across diverse climate conditions.
Composition
Specialized material designed for weather protection and durability on building roofs
Properties
Thickness
45-90 mil (0.045"-0.090")
Standard thicknesses are 45, 60, and 90 mil, with 60 mil being most common for commercial applications. Thicker membranes generally offer greater durability, puncture resistance, and warranty terms.
Weight
0.25-0.40 lbs/ft²
Lightweight material, with the total system weight depending on attachment method and insulation. Mechanically-attached systems are lightest, while ballasted systems add significant weight from stone or pavers.
Elongation
300-450%
Exceptional elasticity allowing the membrane to stretch significantly without rupturing, accommodating building movement and thermal cycling. This property contributes to EPDM's excellent performance in areas with significant temperature fluctuations.
Temperature Flexibility
-40°F to 180°F (-40°C to 82°C)
Maintains flexibility and performance across an extremely wide temperature range, making it suitable for virtually all climate zones from arctic to desert conditions.
Solar Reflectance Index (SRI)
Black: 0-5, White: 78-90
Traditional black EPDM has very low solar reflectance, absorbing heat. White EPDM (achieved through the addition of titanium dioxide and special polymers) provides high reflectivity for energy efficiency in hot climates.
Fire Rating
Class A (ASTM E108)
When tested as part of a roof assembly, typically achieves Class A fire rating. Performance depends on the complete system including insulation and deck.
Applications
Commercial Buildings
Widely used on office buildings, retail centers, warehouses, manufacturing facilities, and other commercial structures with low-slope or flat roofs, particularly where long-term weathering performance is prioritized over initial cost.
Educational and Institutional Facilities
Common on schools, universities, hospitals, and government buildings due to durability, reliability, and compatibility with rooftop equipment and penetrations.
Industrial Facilities
Preferred for industrial buildings with chemical exposure concerns, as EPDM offers excellent resistance to many industrial pollutants, acids, and environmental contaminants.
Retrofit and Recover Applications
Frequently used to recover existing roof systems, including built-up roofing (BUR), modified bitumen, and older single-ply membranes, avoiding costly tear-off and disposal.
Cold Climate Installations
Particularly suitable for northern regions with extreme cold temperatures due to exceptional low-temperature flexibility and resistance to thermal shock and ice damage.
Green Roof and Solar Integration
Serves as the waterproofing layer beneath vegetative (green) roof systems or as the substrate for photovoltaic installations, with specialized versions available with enhanced puncture and root resistance.
Advantages
- Exceptional weathering and UV resistance with minimal degradation over time
- Superior flexibility and elongation, accommodating building movement
- Excellent performance in extreme temperature conditions (-40°F to 180°F)
- Long service life with documented performance exceeding 30+ years
- Good chemical resistance to common environmental contaminants
- Low maintenance requirements with simple repair procedures
- Environmentally friendly with minimal VOCs and potential for recycling
- Available in wide sheets (up to 50 feet) reducing field seams
- Multiple installation options (fully adhered, mechanically attached, ballasted)
Limitations
- Traditional black EPDM absorbs heat, potentially increasing cooling loads in hot climates
- Seam technology historically weaker than heat-welded systems, though modern products have improved
- Susceptible to puncture damage from foot traffic without walkway pads
- Adhesive seams require careful application and are sensitive to contamination
- Black surface shows dirt and debris more prominently than lighter colored membranes
- Potential for oil migration from the membrane over time (plasticizer loss)
- White EPDM typically costs more than black EPDM
- Requires skilled installation with proper tools and techniques
- May require more frequent cleaning in areas with significant airborne contaminants
Sustainability Profile
Sustainable roofing options include recycled materials, cool roofs that reduce energy consumption, and living roofs that provide insulation and manage stormwater. Durability is a key factor in sustainability assessment.