Applying Sealant To A Flat Roof

a flat rooftop
  • 4-12 hours
  • Beginner
  • 50-450
What You'll Need
Trash bags
Rubber gloves
Bright spray paint
Metal putty knife
Alcohol-based cleaner
Flat-blade knife
Roofing cement
Roof tape
Roof patch materials
Dust pan
Roof gravel
Sponge mop

Flat roof sealant is found as not just one product but several products and items that you use in order to properly seal a flat roof. The flat roof sealant process prevents water, moisture, and debris from entering the building or home. Completing the flat roof sealant process isn't difficult, but is one project that can be laborious and very detailed. The article that follows will show you how to seal a flat roof.

Step 1 – Determine Troubled Spots

The flat roof sealant process is easy on new roof constructions but an older roof may be in need of repair. Put on your gloves and climb up to the roof with your materials. You may need to make several trips. Inspect all of the seams to ensure that the roof tar is intact. If you find a seam that does not look completely attached use your knife to check it. Slide the blade under the lip of the seam (where it overlaps). If the blade enters further than 1 inch and moves without restriction you will need to make sure this area is properly sealed. Use the spray paint to mark all areas that need more attention to seal.

Step 2 – Area Preparation

A flat roof can become very dirty and flat roof sealant will not properly stick to dirt so it is important that you clean and prepare the flat roof. Use the broom and sweep away all the debris into the dustpan and dispose of it in the garbage bags. Make use of the metal putty knife to scrape away any gravel on the roof so that the membrane is exposed.

Step 3 – Repairs

If you have found issues with the flat roof then you need to repair them prior to applying flat roof sealant over the entire roof. Use the trowel and place some of the roofing cement over the area and spread it out six inches beyond the spot to repair. It is imperative to fill the exposed membrane. Trim strips of the patching material and press into the cement using steady and even pressure smoothing it out over the area.

Step 4 – Seal the Roof

With the trouble areas patched, you can now work on the rest of the flat roof. Begin at one of the far corners of the roof and apply roofing cement with the trowel. Spread it out until the membrane is covered the cement is even. Work methodically in small sections to ensure proper coverage. Continue until the last area to be done is the area by the ladder.

Step 5 – Clean and Final Seal

After the concrete has dried you will bring a bucket of alcohol-based cleaner and a mop-up to the flat roof. Clean the roof with the cleaner and then apply roofing tape to the seams making sure it smoothed out and pressed firmly to stick. Cover the flat roof with roofing gravel.