Easy Steps for Sealing Your Deck With Thompson’s WaterSeal

Thompson’s WaterSeal includes a complete line of deck sealers and stains for protecting deck wood from moisture and sunlight. Applying a sealer and/or stain typically is recommended every one to three years, depending on the finishing product, deck use, weather conditions, and sun exposure. All Thompson’s WaterSeal products are DIY-friendly, and most need only a single application on a clean, dry deck. You can apply some products with a garden sprayer or paint roller, but for classic deck stain, a paint pad on an extension pole is best.

Choosing a Sealer

Finishing your deck starts with choosing a sealer or stain/sealer. Generally speaking, a sealer does not color the wood and is designed primarily for protection against moisture, while a stain/sealer includes pigment that helps protect against the damaging effects of sunlight (UV degradation) in addition to sealing out moisture. There are three basic categories of sealers or stains: clear sealer, semi-transparent stain, and solid stain. Keep in mind that all deck stains are also sealers.

Clear sealer offers very little UV protection but retains the natural color of the wood. It is not recommended where decks are subject to significant sun exposure. It also must be reapplied more often than most stains, typically every 2 to 3 years, depending on sun exposure. Semi-transparent stain adds some color to the wood and offers a moderate amount of UV protection. It is the most common type of deck finish because it strikes the best balance between UV protection and a natural wood look. Solid stain is similar to paint, as it hides the wood’s grain almost completely. The tradeoff is that solid stain offers the best UV protection.

When to Seal Your Deck

There are a few rules to keep in mind when applying a deck sealer or stain:

• For clear sealer, the deck surface and air temperature must be above 50 degrees Fahrenheit during application and drying time.
• For deck stain, the deck surface and air temperature should be between 50 and 95 Fahrenheit for application and drying.
• The forecast should indicate no rain for at least 24 hours after application.
• The deck surface should be allowed to dry for at least 48 hours before application.

It’s also a good idea to wait for a calm day (little or no wind) to finish your deck, especially if you plan to use a garden sprayer. Stain is best applied when the deck surface is not in direct sunlight.