A GAF contractor spraying an acrylic coating on an asphalt roof.

Roof Restoration: Silicone over Asphaltic

Silicone roof coating protects against leaks

A contractor on roof applying GAF Silicone Mastic

Stand up to ponding water with GAF Silicone Roof Coatings

Choose GAF Silicone Protective Coatings for protection against leaks due to ponding water, wide temperature application window, and tenacious adhesion when restoring existing metal, asphaltic, aged single-ply, SPF, and previously coated roofs.

Featured silicone coating solutions for asphaltic roofs

A container of GAF Unisil High Solids SIlicone Roof Coating, professional grade.

GAF Unisil High Solids Silicone Roof Coating

A high-solids, moisture-cure silicone coating that provides protection against weather elements, UV rays, and leaks due to ponding water for a variety of substrates. View data sheet
See product
A container of GAF Silicone Mastic sealant, professional grade.

GAF Silicone Mastic

A thick, high-build silicone sealant featuring low odor, an easy application, a fast moisture cure, and enhanced adhesion to a variety of substrates. View data sheet
See product

Learn about warranty and guarantee coverage

Warranty info

5 steps to restoring asphaltic roofs with GAF Silicone Roof Coatings

1. Qualify the roof

  • Ensure the asphaltic roof is clean, dry, and tight
  • Perform moisture scan/identify all wet areas
  • Conduct adhesion test to ensure proper adhesion of coating
A contractor power washing a flat roof using GAf's Cleaning Concentrate

2. Prep the substrate

A contractor on flat roof applying GAF Multi-purpose Primer with a roller.

3. Prime the roof

  • Apply a bleed-blocking primer to encapsulate and negate any asphaltic bleed-through
  • Apply GAF Multi-Purpose Primer at a rate of 0.66 – 1.0 gallons per square for smooth surfaces; 1.0 – 1.3 gallons per square for granulated surfaces
A contractor treating a seam on a flat roof with GAF Silicone Mastic

4. Detail seams, flashings, and penetrations

  • Treat all seams using GAF Silicone Mastic
    • Tight seams: apply GAF Silicone Mastic at a rate of 160 linear feet per gallon
    • Loose seams: must be three-coursed with GAF Silicone Mastic and 6” GAF Premium Fabric
    • Three-course loose seams at a rate of 75 linear feet per gallon
  • Treat all curbs, penetrations, and drains with GAF Silicone Mastic and 12” GAF Premium Fabric
    • Three-course at a rate of 160 linear feet per gallon
A contractor coating a flat roof with GAF Unisil Silicone.

5. Coat the roof

  • Apply GAF Unisil Silicone or GAF Unisil High Solid Silicone per the specifications for a 10/15/20-year limited warranty or guarantee1
    • GAF silicone can be brushed, rolled, or spray-applied
  • GAF Unisil Silicone will require a minimum of two coats
  • GAF Unisil High Solid Silicone can be applied in one or multiple coats
    • For one-coat systems ensure the roof is 2:12 slope or less
    • Apply at a maximum of 2 gallons per square
  • Consistently check wet mil thickness for uniform coverage

Download the complete installation steps


Additional Resources

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