How to Waterproof a Concrete Roof

A concrete roof is often seen on businesses as a flat roof, but concrete shingles have been gaining in popularity for use on homes. A concrete roof is as susceptible to the elements as a roof made from other materials. A concrete roof does afford a much longer life than other materials. You can lengthen this life further by waterproofing your concrete roof. The article that follows will show you how to properly waterproof a concrete roof.

Step 1 - Clean Your Roof

In order to waterproof a concrete roof, you first need to start with a clean surface. Use the push broom and dust pan to remove any dirt or debris from the roof. Remove as much of the debris as possible and take your time so you can do this correctly.

Step 2 - Carry Out Mild Repairs

Concrete can crack and produce leaks just like any other roofing material. But the concrete roof is easier to repair and protect. First you need to find any crack, breaks or holes in the concrete roof. These areas are a prime spot for water to erode the concrete further.

Use the silicone caulk and caulking gun to fill all of the cracks and holes. Use the putty knife to smooth out the silicone as well as to push it further into the crack or hole. Repeat this process until you are confident that the imperfection is completely sealed. Allow the silicone to dry before you move forward with waterproofing.

Step 3 - Prime the Concrete Roof

Priming helps in the waterproofing process. First use the seam tape to cover any seams in the concrete. Cover the entire seam with one piece of seam tape and then cut it with the scissors. Make sure the seams are centered. Walk the seams to press them down further. Next apply a coat of concrete primer to the roof. Start at one end and paint yourself into a corner; then use a paintbrush to finish the corner. Wait for the primer coat to dry and determine if you would like to add a second coat.

Step 4 - Waterproof the Concrete Roof

Pour the vapor barrier into the paint sprayer and liberally spray on an even coat to the concrete roof. Try to apply the waterproofing as evenly as possible. You will also overlap with the last spray you placed.

Allow the vapor barrier to dry before you add a second coat. After your final coat dries, you can paint or prime it a different color.