How to Keep a Patio Roof Cooler

Sweep the entire patio roof, using a push broom. Remove all loose grime from the patio roof to prepare for the coating.

Spray the entire roof surface with fresh water from a garden hose to blast any remaining debris off the roof. Let the roof dry thoroughly overnight.

Patch up any leaks on the patio roof by spreading the elastic patching compound 1/8-inch thick over any cracks or damaged roofing with a stiff-bristled brush. Extend the compound 2 inches beyond the cracks and damaged areas.

Cover the bed of elastic patching compound with reinforcing fabric. Press the fabric into the compound.

Spread a 1/8-inch-thick layer of patching compound over the fabric, using the stiff-bristled brush. Let the patched patio roof cure for 48 hours.

Open a container of white elastomeric roof coating and mix it thoroughly with a paint stir stick. Pour the mixed roof coating into a paint tray.

Apply the white coating along the edges of the patio roof, using a 3/4-inch-nap roller. Make one pass around the perimeter of the roof.

Fill in the rest of the patio roof with the elastomeric coating, using the nap roller, working back and forth across the width of the roof, making each back-and-forth pass overlap by 1/2-inch, until the entire patio roof is coated. Metal roofs need 1 gallon of the white coating per 80 to 100 square feet, while porous roofing materials require 1 gallon per 50 to 75 square feet.

Let the coated patio roof cure for 72 hours.

Apply a second coat of elastomeric coating to the patio roof, using the same application procedure used for the previous coat. Let the second coat cure for 72 hours, as well.