How to Seal a Steel Roof

Steel roofs require protective coatings to prevent corrosion and weathering. If your steel roof shows signs of rusting or other wear and tear, it's time for a new sealant. Before you can seal the roof, prepare it by thoroughly cleaning it and applying a rust preventative primer. Depending on the brand of finish coating you select, you may also need to apply a general metal roof primer. While you're working on the roof, take the opportunity to replace any washers or screws as needed.

Wire brush
Rust preventative primer
Steel roof coating primer
Airless spray gun
Flashing grade sealant
Brush
Finish coating
Wet film gauge

Instructions

- 1
  Clean the steel roof of all dirt and debris. Use a wire brush to scrape any loose paint or rust chips off the roof.
- 2
  Seal any areas that had rust with a rust preventative primer. Allow the entire roof to dry completely before sealing it.
- 3
  Apply a steel roof coating primer if the sealant manufacturer recommends it. Not all sealants require a primer. If you do apply a primer, apply it evenly to the entire steel roof with an airless spray gun. Allow the primer to dry.
- 4
  Apply a flashing grade sealant intended for metal roofs to the lap joints, seams, flashing fasteners and penetrations. Use a brush to apply the sealant evenly. Allow the sealant to dry.
- 5
  Apply a finish coating intended for metal roofs. Use an airless spray gun to apply the finish in a thick, even coat.
- 6
  Measure the finish coating once it is dry. Use a wet film gauge to measure the thickness. If it is less than 18 to 25 dry mils, apply another layer of finish coating. You may need a total of two to three layers to achieve a thickness of 18 to 25 dry mils.

How to Make a Valley on a Tin Roof

The World's Best & Most Energy Efficient Roof Covering Materials

Roof Repairs