How to Restore the Roof on a Metal Building

Metal building roofs are known for their longevity, which is largely due to their resistance to mold, pests, fire and harsh weather conditions. Although metal roofing outlasts many conventional roofing materials, it isn’t indestructible to damages. Temperature fluctuations cause metal roofing sheets to expand and contract, resulting in occasional cracks and split seams. Moisture and air also penetrate damaged metal panels, causing the roof to corrode. Damaged metal roofing can leak and ruin a building's interior, so immediately repair and restore a metal roof on a metal building to preserve the building’s structural integrity.

Safety glasses
Rubber gloves
Full-length clothing
Slip-resistant shoes
Wire brush
Broom
Asphalt-based plastic roof cement
Trowel
Reinforcement fabric
Mixing blade
Power drill
Aluminum roof coating
Paint stirring utensil
Paint tray
3/4-inch nap roller
Paintbrush

Instructions

- 1
  Put on safety glasses, rubber gloves, full-length clothing and slip-resistant shoes for protection during the entire roof restoration process.
- 2
  Inspect the roofing for scaly patches of corrosion. Scrub any reddish-brown corrosion flakes off the roof using a wire brush.
- 3
  Sweep the corrosion flakes and any additional dirt, gravel, twigs, leaves and grime off the leaking areas of the roof using a broom. Clean the damaged areas to prepare for plastic roof-cement application.
- 4
  Spread a 1/8-inch-thick coating of asphalt-based plastic roof cement over the previously corroded metal and other leaking areas, such as cracks, split seams and damaged flashings, using a trowel. Extend the roof cement 2 to 3 inches beyond the damaged area. Apply the cement in dry, sunny weather with temperatures between 50 and 120-degrees Fahrenheit.
- 5
  Embed reinforcement fabric in the wet plastic roof cement to strengthen the patch. Press the fabric into the cement using the trowel.
- 6
  Cover the reinforcement fabric with another 1/8-inch-thick coating of the roof cement. Spread the cement 2 to 3 inches beyond the patched area using the trowel.
- 7
  Allow the patched portions of the metal roof to cure for 30 days before coating the roof.
- 8
  Attach a mixing blade to a power drill. Mix aluminum roof coating with drill on a dry, sunny day in temperatures over 60-degrees Fahrenheit. Pour the aluminum coating into a paint tray.
- 9
  Apply the aluminum coating along the edges of the metal roof using a 3/4-inch nap roller. Cut in around roof pipes, chimneys, skylights and other penetrations with a paintbrush.
- 10
  Fill in the remaining metal sheets with aluminum coating at the coverage rate of 1 gallon of coating per 75 square feet of metal roof. Using the nap roller, apply the aluminum coating in even strokes. Start at one edge of the metal roof and continue lengthwise across the roof to the other edge, applying the strokes back and forth across the width of the roof.
- 11
  Allow the aluminum coating two weeks to fully cure.

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