How to Waterproof Decks

Power wash the deck. Before you apply sealant to the deck, you will need to make sure that it is free of any dirt and debris. These tiny particles will cause your sealant to bubble and potentially wear through. If you don't have a power washer, a simple garden hose with a spray attachment will suffice.

Allow the deck to dry completely before proceeding with the sealant. Otherwise, you will be trapping water under the sealant, which will cause the wood to rot from within.

Prepare your deck sealant. Open the can of sealant and stir it thoroughly with a wooden paint stirrer or a ruler. The sealant must be mixed thoroughly to avoid having an uneven finish on your wood.

Apply the sealant. Using a paintbrush, brush the sealant on with the grain of the wood on your deck. Work in small two-foot sections until one area is done and then move on to the next area. Work slowly and make sure the coverage is even. It is better to do two light coats then one heavy coat, as bubbling or dripping can occur if too much sealant is used.

Allow the deck 48 hours to dry before allowing anyone on it. It may be necessary to repeat the sealant process if there are areas that did not receive equal coverage, or if you would like a higher sheen to the wood. However, most wood sealants do provide one coat coverage provided that it is applied evenly.

Repeat this process every 3 to 5 years. Because of the elements your deck is exposed to, you will need to reseal it on a regular basis. In most areas 3 to 5 years is sufficient. However, if your area receives a lot of rainfall or extreme sun and heat, you may need to reseal your deck every 2 years. If you start to see worn spots, this is an indicator that resealing is necessary.