How to Seal Your Deck- DIY Project


Sealing  your deck is a great DIY project that is easy to do. Sealing a deck will add years to the structure’s life. Think of sealant as an anti-aging treatment, a face lift of sorts for your deck. Cleaning and sealing your deck will restore its solid, smooth appearance, if you do it properly.

What type of sealant to use?

If you are not sure what type of sealant to use, as there are many different types of sealants on the market. The temptation is to choose the “all-natural” sealer with oils. Keep in mind that these oils are food for algae an mildew, which will eat away deck sealer. If you opt for a natural sealer, select one that contains mildicides and algaecides. Meanwhile, synthetic sealers contain resins that don’t appeal to mildew or algae. These are water-based and safe for the environment. Water-based, synthetic resin deck sealers are also available in a wide range of colors.

"Sealing a Deck"

Deck Sealant

Preliminary Steps before Applying Sealant

Before you even open the can of sealer, the deck must be cleaned. This job can be quite a workout, and it does involve some elbow grease if you clean by hand. First clear the deck of debris, then clean the surface with an oxygen bleach/water mix. Some sealers can be applied immediately after cleaning, while the deck is still damp. Other products require a completely dry deck. Once you choose a sealer, carefully read the instructions on the label.

The right cleaning tools will make this job much easier. To apply the cleanser for soaking, you can use a handpump sprayer, similar to one you would use for liquid lawn treatments. Allow the liquid to sit on the deck for at least 15 minutes so the solution soaks in. This will make the job of scrubbing much easier. For scrubbing, hand-held plastic scrub brushes with nylon bristles are versatile, and you can purchase them at most grocery or hardware stores. A brush on a pole will save your back as you scrub the deck surface, and a toilet brush is ideal for wedging bristles into tight spaces, such as in between boards or underneath railings.

You can use a power washer to clean off the deck. This will get the job done faster, and you can rent or purchase this equipment from home improvement stores, or rental stores.

However, this is information on hand-scrubbing because we have found that repeatedly using power washers can wear away soft “spring” wood over time, making your deck look like a fishing pier.

Apply sealers with a paintbrush, hand-pump sprayer and lambswool applicator. Brushing on deck sealant is time consuming, but necessary for areas like railings and hard to reach spaces. Otherwise, use a sprayer to apply sealer to deck boards, then smooth with a lambswool pad. This evens out the sealer.

Be sure to check for good weather conditions on the day that you want to do your project. Also, watch the clock with this project. Start the process in the morning or late afternoon, before the temperature climbs past 75 degrees. That way, water and cleanser will evaporate more slowly.

Supplies for Sealing Deck

  • Water
  • Powdered oxygen bleach, (NOT chlorine bleach)
  • Large bucket
  • Hand- pump sprayer
  • Cleaning brushes
  • Deck sealer
  • Paintbrush
  • Lambswool applicator

DIY Steps to Seal a Deck

1. Remove all furniture and container plantings from the deck and sweep off the surface.

2. Mix 6 dry ounces of powdered oxygen bleach per gallon of warm water (one part bleach to 21 parts of water). Stir until it is completely dissolved. Apply cleaning solution to a small area, and start scrubbing. Rinse the area thoroughly with clean water, then move on. Clean the deck first, then move on to railings and high areas.

3. Wait for the deck to dry completely before applying the sealer. (Check instructions as water based sealers can be applied to damp surfaces.)

4. Apply sealer on railings and hard to reach areas with a paint brush. Coat evenly. For more protection, apply two separate coats of sealer rather than one thick layer. For larger surfaces, use a hand spray tank to apply sealer to three deck boards at a time. Once you apply the sealer, follow up with a single swipe of the lambswool applicator. A smooth, continuous stroke will even out the sealer and allow just the right amount to soak into the deck.

5. Allow the deck to dry thoroughly. Replace furniture, and fire up the grill. Time to enjoy!

* Deck material info may be found in this article: Surfacing materials for your Deck or Patio.

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