Many different varieties of caulk are available on the market. Because there is such a large variety of wood applications in the homebuilding process and different kinds of caulk, it's best to ask a professional which kind to use based on your project. When it comes to using caulk on treated wood, the question isn't whether you should (you can!), but what conditions the caulk will be subjected to, and whether the kind you choose will adhere well to the material.

Treated Wood

Wood is treated to preserve it and help give it some protection against fire, weather and the elements. The most common kind is pressure-treated wood. This refers to the process of infusing chemical preservatives into the wood under pressurized conditions. The chemicals are of different categories: waterborne preservatives, oil-borne preservatives, creosote and fire-retardants.

Things to Consider for Caulking

It is best to ask a professional about caulking your treated wood. There is all-purpose caulking, silicone caulking and any number of different caulks for different jobs. You can get expert advice by visiting a home improvement store and talking to a salesperson.

Caulking treated wood is permissible, but the conditions of your project may affect your choice. The three things you'll need from your caulk are that it to stick to the surface it's being used on, that it stretch and recover its shape when the materials expand and contract, and that it remain flexible as it ages. Oily, waxy and pressure treated wood can be difficult to caulk because of adhesion issues. One thing to do to make sure that your caulk adheres properly is to clean the surface thoroughly of all dust, debris and paint chips before you caulk.