Roof Restoration: Silicone over Metal

Protect against metal roof leaks

Roofers on top of commercial roof

Stand up to ponding water with GAF Silicone Roof Coatings

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

Featured silicone roof coating solutions for metal 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
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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
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Two buckets of GAF Mult-purpose primer parts A and B

GAF Multi-Purpose Primer PART A & B

A two-component, 9-to-1 ratio, water-based epoxy primer for optimizing adhesion of coatings over new and existing substrates. View data sheet
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Learn about warranty and guarantee coverage

Warranty info

5 steps to restoring metal roofs with GAF Silicone Roof Coatings

Contractor with brush on metal roof

1. Qualify the metal roof

  • Ensure the roof is clean, dry, and tight
  • Conduct adhesion test to ensure proper coating adhesion
Contractors preparing roof for coatings

2. Prep the substrate

  • Make any necessary repairs to the sheet metal and secure or replace all loose or missing fasteners
  • Power wash the roof using GAF Cleaning Concentrate
  • Install sheet metal crickets behind rooftop units, if needed
roofing contractor treating seams

3. Treat seams and fasteners

  • Treat ridges and rake edges with a roof brush and GAF Premium Fabric embedded into GAF Silicone Mastic
    • Three-course at a rate of 75 linear foot per gallon
  • Seal vertical seams with GAF Silicone Mastic. Typical standing seam profiles do not require seam treatment1
    • Check with GAF Technical Services or the GAF Liquid-Applied Roofing Manual - Seam Treatment Guide
  • Encapsulate all fasteners with GAF Silicone Mastic
Contracting treating penetrations before coating

4. Detail penetrations

  • Treat all curbs, penetrations, and drains with GAF Silicone Mastic and 12” GAF Premium Fabric
    • Three-course at a rate of 75 linear foot per gallon
Roofing contractor spraying coating on flat roof

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

Use these links to connect with the products and people you need to get the job done.

Roofing supply near me

Find distributors that carry GAF low-slope products and systems.
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Contact Commercial Support

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