Roof decks, by definition, are decks that exist over living areas, a garage, or over an area that acts like a deck that is intended to be waterproof, yet can be walked upon.

Roof deck applications are generally quite expensive to build and have a multitude of waterproofing problems and applications. A system that our company has developed, and that has worked well for many years, is the one described below. This system consists of the actual deck which should be relatively waterproof if constructed properly at the outset.

The plywood, or wood, should be waterproof and constructed with a CDX or exterior grade of wood. It is suggested if the deck has not been installed yet to give it one coat on all sides with Vapor-Barrier or Elasto-Barrier. These two products have a great deal of rubber in them and are designed to resist water.

After the deck has been installed, the next step is to fill all cracks and crevices with Blue Max trowel-grade coating and filler. This blue filler and sealant can fill cracks. Make the surface as smooth as possible. Flashing of two to three inches should be applied over the outer edges with an adhesive caulking and fastened down with screws or nails. Flashing tucked under the T-111 or equivalent siding at the wall will be necessary. Seam tape can be used on other areas where two surfaces are unlike that need to be joined.


The tools for application will be a push broom, ¾ inch nap roller, utility knife, paintbrush, and rubber gloves. Coveralls are recommended to keep from ruining clothing. Wearing old shoes that you can throw away later is recommended.

Read all label instructions before beginning. Always run a test patch first in an inconspicuous area, to ensure that proper adhesion and drying occur and the product works to your satisfaction.

You will need some coating, as well. You will use 3 gallons of Elasto-Barrier, 2 gallons of Safe-T-Deck and a roll of roofing fabric (42 inches wide and has about 250 square feet of coverage) for every 100 square feet of surface. Roofing fabric looks like fiberglass and goes down like fiberglass. The coating is first poured out for about 10 to 15 feet and spread out about 45 to 60 inches wide. This is done by simply pouring out one or two gallons of Elasto-Barrier from the container. Start at one end of the deck, and work to the other end where you want to stop. Elasto-Barrier is spread out wide enough with a paint roller or pushes broom so the roofing fabric becomes saturated with the wet coatings and the excess coating is pulled off to the next area of application. Overlapping of the fabric is possible but will leave a seam. It is best to try and not have a seam, because it can be seen in the final outcome. After the coating has totally cured for 24 – 48 hours, two more coats of Elasto-Barrier will be applied after the fabric layer. Two more coats of Elasto-Barrier, then two coats of Safe-T-Deck and you are done.

If you already have a waterproof deck, you may wish to just use the Safe-T-Deck. Safe-T-Deck is a thick elastic paint that dries rapidly, waterproofs, and provides a skid-resistant surface. Elasto-Barrier is a highly elastic rubber product designed to such a level that it could waterproof a paper bag if need be. That is a huge advantage in waterproofing technology. Elasto-Barrier is grey in color. It is a great advantage to the homeowner since the DIY (Do-It-Yourselfer) would like to do many of his own projects, and a waterproofing specialist is not always needed or desired. These systems can easily run ten dollars a square foot, or one thousand dollars every one hundred square feet. In this way, one can do it for a tenth of that. The application is simply to pour out the product and paint it on the surface.

This is simply one suggested method. Since the application cannot be controlled, these are simply suggestions. The user assumes the responsibility of the application and the weather and the manner of the application.

Good luck with your application on your deck. Many people have enjoyed this application and most decks last for many years. A coat of Safe-T-Deck is a good thing to do when it gets dirty. Safe-T-Deck is an adhesive coating and can be applied to wood decks quite easily. Over concrete, it is important to power wash first, then when dry, apply Ames’® Super Primer, then coat with Safe-T-Deck.

Need help? Call toll free 1-888-345-0809 to speak with a waterproofing expert.