A Step by Step Guide To Cleaning and Sealing a Deck

So you're looking to seal your deck but you don't know where to start? Well we're here to help you out. 

So you want to seal your deck! Before you get started, there are a few things to keep in mind. If your deck is newly built, wait a minimum of 30 days before sealing the wood. Lastly, be sure you understand the difference between sealing, staining, and painting.

Sealing a deck uses a wood sealant that prevents moisture from penetrating the wood grain, and prolongs the life of your deck, and cuts down on long-term maintenance. These sealants usually don't have a deep color penetration and typically look lighter after drying than an actual stain. They also offer less UV protection than a stain.

Staining a deck uses a wood stain, a mixture of a wood pigment with added UV stabilizers. Stains are excellent at giving your deck a deep, rich color. The added UV protection provides the stain with a longer lifespan. The downside of only using a wood stain is that even high-quality wood stains only have moderate water repellent qualities. The wood will begin soaking in water long before the color fades.

Painting a deck can offer both color and water sealing to the wood. The downside to this approach is that paint has a shorter lifespan than either stain or sealant. If you choose to go this route, wait at least six months after any new construction to dry the wood entirely. Any moisture trapped within painted wood can cause the paint to fail prematurely.


Sealing a deck can be a costly and time-consuming process. You certainly don't want to undertake this project if you don't need to. Before starting or buying any materials, you'll first want to make sure the wood is ready to accept a sealant. The first step in accomplishing this is called a water test. The water test is the easiest way to ensure that the wood can absorb sealer or finish. Either wait for it to rain or sprinkle a little water on your deck. If the water soaks in immediately, the wood on your deck is ready to absorb a sealant. If it beads up or stands on the deck, your deck may not need sealing yet.


Before sealing the deck, you'll want to get it ready. This process begins simply by removing all furniture from the deck area. If there are plants or shrubs near the deck, you'll want to protect them by spraying them with water and then covering them with plastic. Water and covering your nearby plants keep them from getting too hot and protects them from the stain. Also, cover any nearby wood structures, such as siding or benches that you don't want to stain. Next, you'll want to inspect your deck flooring for any loose planks, splinters, or breaks. Replace any boards that can't be easily repaired and be sand down any rough surfaces and splinters you find.


Next, you'll want to clean the deck thoroughly by using a specially made deck cleaner. These cleaning agents have added surfactants that help scrub away dirt and grime that may have settled in the wood grain. A pressure washer can come in handy during this step, but a quality deck brush is a great alternative. After the cleaner has soaked in, spray everything with a garden hose or pressure washer, then allow the deck to dry for two days.


Once the cleaning is complete, and the deck is thoroughly dry, you can begin the sealing process. A few key things to keep in mind about this process:

  • It's best to wait for two days in a row of dry, warm weather for the sealing step, but less than 90 degrees Fahrenheit.
  • It is best to start in the early morning, giving yourself plenty of time before the hottest part of the day.
  • Remember to stir the sealer rather than shaking it. Shaking the sealer can result in bubbles forming in the finish.

Start sealing by applying a thin, even coat of sealer over a small board section with a paint roller and an extension handle or a paint sprayer. It is best to go slowly during this process and focus on completing one full coat over the entire deck before considering a second. Trying to apply a second coat too early can result in thick drips that will dry unevenly and cause a mess. You can use a paintbrush to apply the sealer in corners or difficult areas to reach with a roller.

Now that your deck is fully sealed from the weather comes the most challenging step: waiting two full days before using or moving your furniture back onto the deck! While sealing your deck can be a time-consuming DIY project, it is also gratifying and an investment in a valuable property enhancement.