To Prime or Not to Prime...That is the Question

To Prime or Not to Prime...That is the Question

This parapet wall and low slope surface has been primed with an asphalt-based primer prior to the application of Peel & Seal®.

This parapet wall and low slope surface has been primed with an asphalt-based primer prior to the application of Peel & Seal®.

The headline says it all. And builders, whether the more experienced contractor, manufacturer, or dealer, should be asking this question. Priming the surface can be a critical step.

For this continued dialogue on MFM Building Products’ roster, we’ll discuss Peel & Seal®. This benchmark product is the original, self-stick roll roofing specifically designed for low-slope residential and commercial applications. Peel & Seal®’s patented formula (consisting of laminated aluminized foil, high-density polymer films and a thick layer of rubberized asphalt) provides a durable and maintenance-free roofing surface.

In this photo, Peel & Seal is being installed directly to the primed surface. No need for any special glues, coatings, hot torches, etc.

In this photo, Peel & Seal is being installed directly to the primed surface. No need for any special glues, coatings, hot torches, etc.

However, some substrates require an asphalt-based primer prior to the application of the product — very important for the best possible adhesion. In fact, the better the contact with the substrate, the better that Peel & Seal® will perform. In some cases, a surface does not require priming and the product can be adhered directly, but any surface containing dust, debris or dirt will compromise the bond. 

Here is the finished product. Peel & Seal® is designed to be permanently exposed to the elements and carries a 10-year limited warranty.

Here is the finished product. Peel & Seal® is designed to be permanently exposed to the elements and carries a 10-year limited warranty.

MFM Building Products gets a lot of technical calls with questions about applying Peel & Seal® to various surfaces, so below are some common construction surfaces and suggested preparations. In the end, though, the key to correct installation is a clean, dry, and flat surface.

COMMON CONSTRUCTION SURFACES:

  • Wood (weathered wood must be primed)
  • Metal (rusty metal must be primed)
  • Plywood (weathered plywood must be primed)
  • OSB (weathered OSB must be primed)
  • Composition Board (must be primed)
  • Fully Cured Masonry (must be primed)
  • Rigid Insulation Board
  • Smooth Asphalt Roofs
  • Fiberglass Base Sheets (must be primed)
  • EPDM Roofs (must be primed with an MFM-approved EPDM primer)
  • Mobile Homes, Campers, RV Roofs

Please let us know if there are any surfaces that you have had problems with or you can contact MFM Technical Services at 800-882-7663.