How to waterproof a metal shed

While metal sheds are durable, they are not very energy efficient. The roof on a metal shed absorbs heat from the sun, causing the shed's interior to heat up. Waterproofing a metal shed lowers the roof's surface temperature and drastically reduces cooling costs. Failure to waterproof a metal roof allows moisture to seep under the roof, causing internal corrosion. Waterproof a metal roof a few months after installing the roof, to protect the roof and reduce energy costs.

Sweep the entire roof with a push broom to remove dirt and debris. Spray the roof with water from a garden hose.

Use a screwdriver to tighten or refasten any loose screws on the roof. Dry the roof thoroughly with a clean towel.

Inspect the roof for cracks greater than 1/8 inch wide. Caulk the cracks and fasteners with trowel-grade coating.

Apply seam tape over all horizontal and vertical seams, joints, cracks, flashings, vents or anywhere two different surfaces meet. The seam tape will provide additional protection and reinforcement to the metal roof.

Apply two coats of metal primer to the entire roof with a roller brush. Allow each coat to dry thoroughly.

Paint the entire roof with a coat of acrylic latex roof coating, using the roller brush. Allow the paint to dry.


Use a pressure washer instead of the garden hose. Apply the metal primer and roof coating when the temperature is 4.44 to 32.2 degrees Cor best results.

Things You'll Need

  • Push broom
  • Garden hose
  • Screwdriver
  • Clean towel
  • Trowel-grade coating
  • Seam tape
  • Metal primer
  • Roller brush
  • Acrylic latex roof coating
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About the Author

April Dowling first started writing in high school and has written many news articles for newspaper and yearbook publications. She is currently pursuing a career as an online writer and affiliate marketer. Dowling writes for several websites and keeps many blogs.