Elastomeric roof coatings represent a specialized category of protective coverings that have revolutionized roof maintenance and restoration over the past few decades. These unique formulations create a seamless, flexible membrane that shields your roof from the elements while extending its functional lifespan. Unlike conventional paint or basic sealants, elastomeric coatings possess remarkable elastic properties that allow them to stretch, flex, and recover as your building and roofing materials naturally expand and contract.
What Defines an Elastomeric Coating?
The term "elastomeric" refers to the coating's rubber-like elasticity—its ability to stretch and return to its original shape without damage. This key characteristic allows these coatings to:
- Expand and contract with the roof during temperature fluctuations
- Bridge small cracks and gaps in the substrate
- Form a continuous, seamless waterproof membrane
- Resist damage from normal building movement and settling
True elastomeric coatings can stretch 100% or more of their original size and recover without cracking or splitting, making them ideal for protecting roofing substrates that experience thermal movement.
Common Types of Elastomeric Roof Coatings
While there are several varieties of elastomeric coatings, the most common types include:
Acrylic Elastomeric Coatings:
- Water-based formulations
- Excellent UV resistance and reflectivity
- Cost-effective and widely used
- Good adhesion to many substrates
- Environmentally friendly with low VOCs
- Typical thickness: 15-20 mils when properly applied
Silicone Elastomeric Coatings:
- Superior ponding water resistance
- Excellent weatherability and UV stability
- Maintains flexibility for decades
- Higher cost but longer lifespan
- Typical thickness: 20-30+ mils when properly applied
Polyurethane Elastomeric Coatings:
- Superior abrasion and impact resistance
- Good chemical resistance
- Available in aromatic (base) and aliphatic (top) coat systems
- Higher cost and installation complexity
- Typical thickness: 20-30 mils in multi-coat systems
Butyl and SEBS Elastomeric Coatings:
- Excellent water resistance
- Good elongation properties
- Solvent-based formulations
- Less common in modern applications
How Elastomeric Coatings Work
When applied to a roof surface, elastomeric coatings create a protective barrier that shields the underlying substrate from:
- Water infiltration: The seamless membrane prevents leaks and moisture intrusion
- UV radiation: Reflective pigments (especially in white coatings) bounce sunlight away
- Thermal shock: The coating's flexibility accommodates expansion and contraction
- Weather exposure: Resistance to wind, rain, and environmental contaminants
The coating cures to form a thick, rubbery membrane that adheres tightly to the roof surface, essentially creating a new weatherproof layer without the need for roof removal.
Application Process
A typical elastomeric coating installation follows these steps:
- Thorough roof cleaning: Pressure washing and removal of all debris and contaminants
- Repairs and preparation: Addressing existing leaks, cracks, seams, and problem areas
- Primer application: When required for proper adhesion to the specific substrate
- Base coat application: Initial layer applied by spray, roller, or brush
- Reinforcement: Fabric reinforcement at seams, transitions, and problem areas
- Top coat application: Final layer(s) to achieve specified thickness and protection
- Inspection and quality control: Ensuring proper coverage and mil thickness
Benefits of Elastomeric Roof Coatings
Property owners choose elastomeric coatings for numerous advantages:
Protection and Longevity:
- Extends roof life by 5-15+ years (depending on coating type and maintenance)
- Creates a renewable surface that can be recoated periodically
- Prevents leaks and water damage to building interiors
- Reduces thermal stress on roofing materials
Energy Efficiency:
- Highly reflective white coatings can reflect up to 80-90% of solar radiation
- Reduces cooling costs by 10-30% in hot climates
- Qualifies for Energy Star and cool roof programs
- Helps mitigate urban heat island effect
Cost-Effectiveness:
- Significantly less expensive than roof replacement
- Installation without business disruption
- Tax benefits (often classified as maintenance rather than capital improvement)
- Reduced lifecycle costs through energy savings
Environmental Benefits:
- Low-VOC options available
- Reduces landfill waste by avoiding tear-off
- Lowers energy consumption and carbon footprint
- Many formulations are water-based and environmentally friendly
Ideal Applications for Elastomeric Coatings
Elastomeric coatings work well on various roof types:
- Metal roofing (prevents rust and seals fasteners)
- Built-up roofing (BUR) and modified bitumen
- Single-ply membranes (EPDM, TPO, PVC)
- Concrete and foam roofs
- Asphalt shingles (in some cases)
Limitations and Considerations
While elastomeric coatings offer many benefits, they're not suitable for every situation:
- Most acrylic elastomerics aren't recommended for areas with prolonged ponding water
- Proper surface preparation is critical for adhesion and performance
- Some substrates require specific primers or coating systems
- Application temperature and weather conditions affect installation
- Professional application is recommended for warranty protection
- Regular maintenance and inspection are necessary for maximum lifespan
Choosing the Right Elastomeric Coating
Factors to consider when selecting an elastomeric coating include:
- Local climate conditions (temperature extremes, rainfall, UV exposure)
- Roof type, condition, and slope
- Budget constraints vs. long-term performance needs
- Energy efficiency goals and potential rebates
- Warranty requirements
- Building use and expected lifespan
Maintenance Requirements
These practices help maximize the lifespan of an elastomeric coating:
- Schedule regular inspections (twice yearly and after severe weather)
- Keep the roof clean and free of debris
- Address any damage or punctures promptly
- Recoat as recommended by the manufacturer (typically every 5-15 years)
- Maintain proper drainage to prevent ponding
The Bottom Line
Elastomeric roof coatings offer an excellent solution for extending roof life, improving energy efficiency, and protecting your building investment without the disruption and expense of roof replacement. With proper application and maintenance, these flexible, protective membranes can provide years of reliable service while reducing energy costs and environmental impact. A professional roofing contractor can assess your specific situation and determine if an elastomeric coating system is right for your roof.