How to Waterproof a Flat Roof Deck

What You'll Need
Drop cloth
Waterproof sealer
Small paint brush

A flat roof deck is a wonderful area in your home where you can hold parties or other outdoor functions, but it is also important to waterproof it, as damaged wood is not very aesthetically pleasing and would look old right away. Usually, flat roof decks are made with wood material and as we all know, wood ages and is not resistant to water damage. Nor is it resistant to insects, such as termites and wear such as wood rot, unless pressure treated lumber is used. And when choosing a sealer, make sure you consult your local hardware professional what type of sealer to use on your flat roof deck. It’s also best to check your local weather forecast for the rain schedule. You do not want rain to come while you are waterproofing your deck with sealer. Rain should not be in the forecast for at least 48 hours or better yet, 72 hours.

Step 1 – Clean the Deck                   

Make sure it’s free from dirt and debris. Any dirt and debris will not make your waterproofing sealer stick to the lumber.

Step 2 – Cover the Deck

Cover furniture or items on your flat roof deck that are not meant to be waterproofed with the drop cloth. Any sealer that will get on your other furniture can cause aesthetic damage. It is best to get everything out of your deck when waterproofing and put them at a safe distance.

Step 3 – Apply Sealer                       

Take your roller and start applying sealer on your deck. Apply by making an even, thin layer of sealer. It is very important to apply sealer on every part of your deck because water damage will have to start somewhere and that unsealed part can be it. Inspect well before you jump to the next part of the deck that you will apply sealer on.

Step 4 – Remove Excess Sealer

If bubbles or puddles form on the layer of waterproofing sealer, use your small paintbrush to even it out and remove excess sealer. If sealer is applied evenly, your deck will be less likely to discolor in the future.

Step 5 – Let Sealer Sit                      

Let sealer sit for 15 to 30 minutes.  Avoid getting dust or debris while your deck waterproofing sealer is still wet, as this can also cause discoloration on your deck and unsightly bumps.

Step 6  - Dispose of Sealer       

Check how you can dispose of empty containers properly, as these cans are toxic. If you should keep the remainder of the sealer for future touch-ups and cover the container properly. Read label for storage instructions. It is best not to keep these containers in warm areas.

Step 7 – Leave the Deck                  

Do not walk or use the deck within 48 hours from the time you finished applying the waterproof sealer. More time should be given if it is humid outside or if it doesn’t look completely dried.