Can You Topcoat a Deck?

Cleaning and Brightening

• Before applying a topcoat to your deck it is important to clean the deck with a commercial deck cleaning product. The cleaner can be rolled or mopped on and then sprayed off with a strong garden hose attachment. A power washer may damage your wood, and is not recommended. Even new wood decks should be cleaned before topcoating. Using a wood brightener after cleaning will restore the natural color of the wood.

Preservers

• Wood preservers are penetrating products that protect wood from insects, molds and fungus. They are either oil-based or water-based and can be applied to old wood to prevent further deterioration or to new wood to prevent decay. Wood preservers can be tinted or clear and are applied prior to the topcoat. Oil-based preservers will require a solvent such as turpentine or paint thinner for cleaning brushes.

Sealant

• A sealant is a non-penetrating topcoat that is applied to prevent moisture damage to your deck and is available with additives for UV protection and mildew resistance. If you do not want your wood to turn gray, you will need to use UV protection. Sealants may be water-based or oil-based and come in a variety of finishes from flat matte to high gloss. Keep in mind that the high-gloss topcoat may be very slippery when your deck is wet. Consider adding a slip-resistant product to your sealant if you are using a high-gloss sealant. Sand will work as an anti-slip agent but it will be sharp and uncomfortable. Commercial anti-slip products have rounder particles that will be more comfortable on bare feet.

Volatile Organic Compounds

• VOCs are compounds that are harmful to the environment and to humans and are often found in oil-based deck maintenance products. VOC restrictions vary from state to state, and VOCs have even been banned in some states. Due to environmental concerns, there are now oil-based stains that do not contain VOCs. Be sure to read deck maintenance product labels thoroughly and ask for the material safety data sheet to familiarize yourself with the proper handling and safety concerns for any deck maintenance product.