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How to Waterproof Plywood

July 22, 2019 by Curtis Lumber & Plywood

Plywood is used in nearly all construction projects in some capacity. You can use it both indoors and outdoors, making it particularly versatile. Because it can be used pretty reliably for outdoor projects, you want to ensure that you know how to waterproof plywood. This will allow you to protect it enough to ensure it will not rot or grow mold. In fact, projects used indoors often also require that you properly waterproof your plywood. Given the damage water can do to houses, you do not want to risk getting water or mold damage.

Before you learn how to waterproof plywood, you need to make sure you know where the plywood will be used. There are different concerns when it comes to plywood that will be used indoors versus plywood used for outdoor projects. Because of this, you need to tailor your waterproofing approach to the kind of project you will be completing.

If you are using the plywood in an area that has minimal concerns related to moisture and mold, you likely can get by using just an anti-fungal preservative, which is very easy and straightforward to apply. That obviously is not the case if you are dealing with something that will be outdoors. That would likely require something far more extensive for protection such as a waterproofing layer. That layer is not particularly challenging to install but the approach is different than what you would expect to do when just using a spray-on preservative.

Types of Waterproofing

There are several different kinds of waterproofing materials and methods used to protect plywood. You want to ensure you use the one that is most suitable for your plywood’s application. The waterproofing material you will most often see is a spray-on or paint-on type of waterproofing. Usually this kind of waterproofing is a liquid latex that you put on the plywood when it is wet. As the material dries, it creates a layer that protects against moisture. This material can be purchased at nearly any hardware store and is easy enough to apply independently. You simply put it on and wait for it to be completely dry.

There are also sealers and oils that can be used to protect against water as well membrane systems and sheet plastics, both of which are available to ward off moisture damage. Again, you will need to use the system and process that works best for your particular project.

Application

The way you apply your liquid will depend on if you are using plywood for building purposes or as a finish material. Most of the time, you can very simply apply the liquid substance using a roller or a brush. Sometimes you can even just spray it on using an electric sprayer like the kind you would use for spraying on paint. You can think of this application as very similar to a painting project.

If using plastic sheeting for waterproofing protection, it needs to be stapled or tacked up usually. That same application process usually applies to interlocking membranes as well. You really only ever use interlocking membranes when the plywood you have is going to be used under natural stone or tile. For plywood that is finished, you will usually only be able to use spray-on sealer since you want to make sure you keep the existing look of the wood.

Follow Guidelines

It can be really crucial to follow the guidelines of your product’s manufacturer when you are learning how to waterproof plywood. You want to install a protective layer for your plywood but that will really depend on the application of the plywood itself. Take for example if you are putting plywood beneath ceramic tile.

You want to make sure you are using the guidelines set by the tile’s manufacturer to make sure you are using the recommended method of waterproofing. This method really applies to every waterproofing method you could use as well as every plywood’s application. Not only will it lead you to a more productive outcome, but you want to make sure you can keep any warranty that might apply to the products you are using. Not following guidelines is a sure way to void any warranty, which means you will be starting over again.

If you need to purchase plywood or you have additional questions on how to waterproof plywood, reach out Curtis Lumber & Plywood. Every project is different, and you want to ensure you are using the right types of plywood and that you are protecting it properly before you get started. Otherwise, you might find that you are doing the same project over again far too soon. Water is the death of houses, but you can avoid water damage, as well as mold growth by ensuring you follow the proper guidelines for waterproofing your plywood.

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