Can You Waterproof Plywood?

Nov 14, 2022

Sometimes our projects might leave exposed portions of plywood, which are not impervious to the elements by any means. While a versatile medium, you’ll want to ensure that you’ve taken measures to protect any exposed portions of plywood from weather. Can you waterproof plywood to do this? The quick answer is: YES! Here’s a DIY guide we’ve created to show you how simple and easy this is to do.

What Can You Put on Plywood to Make it Waterproof?

You have a variety of options to consider when looking for a solution for your plywood treatment. You might be wondering: can you paint plywood to make it waterproof; or can you waterproof thin plywood?

In short, the best solution here is to use Liquid Rubbe r Deck Coating, which basically rolls right on to the plywood you are waterproofing like a coating of paint. Once applied, it will bond and cure to create a watertight barrier that will prevent moisture penetration while also protecting the wood from other elements, like UV rays, heat, wind, rain, snow and so on.

How Much Liquid Rubber Deck Coating Will You Require?

A good rule of thumb is that you’ll want about 1 gallon of Liquid Rubber Deck Coating for every 50 square foot piece of plywood. It’s advised that you use at least 3-4 coats for optimal coverage and protection. For every 100 square feet you plan to waterproof, make sure you’ve accounted for that with at least 2 gallons of deck coating in your supplies list, although we do advise that you use all the recommended material for the best coverage and protection.

Before you waterproof your plywood, you’ll want to make sure that you have all of the necessary supplies.

Things you’ll need:

How to Waterproof Plywood with Liquid Rubber

Step 1: Fill & Sand Surface Areas

Before you do anything else, make sure you’ve cleaned the surface areas and filled any gaps you find in the plywood with standard wood filler. After the wood filler dries, use the sandpaper to smooth things out to create a flat and seamless surface.

Step 2: Clean the Surface

Make sure the exterior surface of the plywood is clean and clear of debris and dirt. Then using a standard large paint brush, apply two or three coats of Liquid Rubber Multipurpose Epoxy Primer.

Step 3: Use Geotextile to Seal Edges

Allow a few hours for the primer to set and dry. Next, use the Liquid Rubber Geotextile to create a waterproof seam between anywhere that the edges of plywood connect with other sheets.

Step 4: Apply Liquid Rubber Deck Coating

Using a paint roller, carefully apply the first coat of Liquid Rubber Deck Coating. Make sure to use even strokes and to apply a thick coat to each pass. Allow each coat to fully dry and cure before applying the next one. We advise you to apply at least 3 coats of deck coating.

That’s all there is to it! As you can see, it’s pretty straightforward to waterproof plywood using liquid rubber products.

What Happens If It Rains?

For the best results, take a look at the weather forecast in your area before you plan your project out, providing for a window in between rain days (you’ll want at least 48 hours of dry time for the rubber membrane to fully set and cure).

Can You Waterproof Painted Plywood?

The simple answer here is: No. The paint will have to be sanded away first, and you’ll want to use primer before you waterproof it. This way, the liquid rubber can fully bond with the plywood and protect it.

Need Even More Tips?

We’ve got you covered! Check out some other helpful DIY guides we’ve created that can give you even more tips and tricks.