Elastomeric Roofing - TOPCOAT Surface Seal SB Primer

Topcoat Surface Seal SB Primer


TOPCOAT® Surface Seal SB Primer is a light gray, solvent-borne, thermoplastic rubber based, industrial primer/rust inhibitor that must be applied to any areas of rust before TOPCOAT® Surface Seal SB Roofing Membrane can be applied. It is ideal for priming aluminum coated metal roofs, which are beginning to rust through the coating. Surface Seal SB Primer can be used to brush-treat small scattered areas of rust, or it can be sprayed over areas of widespread rust. Heavy, flaking rust and scale must be removed by scraping, wire brushing, or grit blasting, followed by power washing with water.


SB Primer is designed for priming rusty metal roofs prior to applying TOPCOAT® Surface Seal SB Roofing Membrane, TOPCOAT® Membrane or Topcaot®FlexSeal. Unlike TOPCOAT® MP-300, it is compatible with asphalt-based coatings and cements. Substrate shall not pond water for a period longer than 48 hours. Surface must be free of ponding water, ice, snow, and debris prior to application. Do not apply at temperatures below 32°F. Substrate temperatures must be below 120°F when applying product.

  • Can be applied at temperatures as low as 32°F

  • Forms a flexible seal that will not become brittle

  • Limited material warranty available for up to 10 years*

  • Can be part of 20-year Guarantee**

  • Available in 1-gallon and 5-gallon pails

For application questions, please contact GAFMC Contractor Services at

Applicable Standards

ASTM D-412, ASTM G-21, ASTM B-117, ASTM D-1475, ASTM C-794, ASTM E-1644

Note: Repair leaks promptly to avoid adverse effects, including mold growth

*See warranties and guarantees for complete coverage and restrictions.
**When used as a part of a multi-ply system

TOPCOAT® Surface Seal SB Primer Technical Data
Application Rate: 1 gallon/100 sq. ft.
Application Method: Airless sprayer or brush
Application Temp (air, surface): 32°F – 120°F
Drying Time (75°F, 50% RH): Approximately 2 hours
Wet Mil Thickness: 16 wet mils
Dry Mil Thickness: 7 dry mils
Total Solids (by weight): 60% ± 2%
Total Solids (by volume): 45% ± 2%
Specific Gravity: 1.21 ± 0.1
Weight per Gallon: 10.1 ± 0.5 lbs
Viscosity (75°F): 10,000 ± 2,000 cps
Storage: Store in well-ventilated area at 50°F to 80°F; protect from freezing
Shelf Life: 1 Year
Clean-up: Mineral Spirits


All documents are U.S. English unless otherwise noted

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