How To Pressure Wash (and Treat) Your Wood Deck Without Damaging It

Unlock the secrets to revitalizing your deck with our comprehensive guide on pressure washing, featuring a detailed video demonstration, step-by-step instructions, and answers to frequently asked questions. Dive into this essential read to transform your deck from weathered to wonderful with ease and efficiency.

Video Guide to Pressure Wash Your Deck:

Difference Between Pressure Washing A Wood Deck and Composite Decking

A wood deck is made from fine-quality lumbers such as cedar, pine, larch, and spruce, ideal for outdoor environments. After pressure washing and cleaning, it’s advisable to apply stains and sealants to the wood deck. Staining maintains the condition of natural wood surfaces. Typically, it uses wood stripper and wood brightener for cleaning. Do not treat the deck with chlorine bleach. It will strip the deck of its natural colors.

While composite decking is composed of a mix of plastic and wood with a coat or cap of vinyl. It is designed to ward off dirt, making it simple to clean and necessitating minor upkeep. This type of decking is highly flexible in terms of patterns and color options. Power washing a composite deck involves cleaning without the need for a sealer. Formulated bleach can also be used, but with certain knowledge.

Overall, the step-by-step process of pressure washing both wood decks and composite decking is similar and differs only with the use of stain and solution.

How To Pressure Wash A Deck Without Damaging It

A deck is an investment for homeowners. It adds value to your home by increasing living space. Protect that investment by cleaning a dirty deck occasionally and re-treating it every 2–3 years. This routine of maintenance work will not only sand off the dirty look but also extend its life by many years.

It is important to follow these steps and techniques on how to pressure wash a deck to avoid damaging the wood or surface of the deck. The cost of repair can be quite high if not handled with care.

Surface Preparation Of The Deck

First, protect yourself. Dress accordingly so that it covers your body.
Make sure to protect furniture and plants around the deck with sheets of plastic.
For a wooden deck, use 80-grit sandpaper over the deck surface.
Broom away all the dust and make sure the entire deck is clear.

‍Pressure Washing Your Deck

The recommended pressure setting for pressure washing a deck is typically between 1,500 and 2,000 pounds per square inch (PSI).

Use your pressure washer with a 40-degree nozzle tip to wet the surface before applying any solution.
Pre-rinse off any dirt and debris.
Hold the pressure washer at a slight angle, with a distance of about 12–18 inches from the surface of the wood. Use broad, sweeping motions to cover the entire area evenly.

Tip: “You can install a swivel in your pressure washer wand. It allows the gun to completely rotate, helping you to move around and avoid the hose.” – Ed Kennedy, Professional Pressure Washer, Kennedy Exterior Cleaning

3. Cleaning Your Deck With Solution

Solution for Wood Deck:

Use a wood stripper and wood brightener in two separate steps to assist the pressure washing. Use products specific to the type of wood your deck is made of.
For wood stripper, get the surface all wet and then apply stripper using a pump sprayer or paint brush. Let it sit for 15 minutes without letting it dry.
Rinse with a pressure washer on a light spray.
Then apply the brightener using a pump sprayer; this will remove any discoloration. Let it sit for 15 minutes without letting it dry.

Solution for Composite Decking:

Check what type of dirt is present on the deck.
According to Ed Kennedy, professional pressure washer, for mold and other organic stains, bleach is efficient at removing them. Other sources of stain, like rust and oxidation, require a special chemical.
Ed Kennedy recommended 3% bleach solution in a bucket of water, it is recommended to use an injector, an X-Jet M5 nozzle, that is inserted at the tip of the pressure washer wand. It automatically reduces the solution to 1.5%, which is suitable for a deck.
Use a pop-up spray to hit the delicate sections that might have been missed, such as the side railings of the deck.

After putting a solution in place and letting it sit for a while, You can use a brush to deal with stubborn spots. Preferably, slightly brushing the whole deck is a good idea, so it can help the solution sip through the area and catch the dirt.

4. Rinsing Off The Deck

After 15 minutes, you can now use the pressure washer with the 25-degree nozzle to give the deck a final wash, removing all the stains and the remaining brightener detergent in an even sweeping motion with different angles. On the vertical railing, etc., rinse the bottom up.

5. Staining Your Deck (For Wood Deck)

This is optional, but staining your deck can provide an extra layer of protection and will last for a longer time before pressure washing again.

After the deck has been power washed, we recommend allowing it to dry thoroughly for safety reasons; typically, we advise waiting 48 hours before applying any sealant or finishes for maximum protection.
Before staining, cover your house with plastic or anything else you don’t want to get a stain on.
Apply the stain with a paint roller in two thin coats over the surface. Use a paintbrush for the tight spots.
What treatment or stain should you use?

Well, it’s up to you, as there are four types of stains:

Clear/natural transparent type
Toner (which brings out the look of the grain)
Semi-transparent (mostly masks grain)
Solid (covers it completely)

UV protection is greatest with solids and least with clear or transparent.

The type of stain to use depends on the grain of the wood on your deck.

Let it dry for 24 hours, then have a celebratory party.

How Often Should You Do Deck Cleaning?

The recommended frequency for pressure washing a deck depends on various factors, such as the climate, level of foot traffic, and surrounding vegetation. As a general guideline, it is advisable to pressure wash your deck at least once a year to remove dirt, grime, and mildew buildup. However, in areas with high humidity or heavy rainfall, it may be necessary to pressure wash more frequently, perhaps every six months.

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Can You Use a Surface Cleaner for Decks?

Low-pressure surface cleaner can be used on decks but is not recommended. Most pressure washers’ service in the center comes with pretty high pressure. There is a chance it could rip deck material. Most pressure washers often recommend this be used on concrete surfaces.

Sources

Lowe’s Home Improvement has a deck projects page that explains in summary how to clean your deck with a pressure washer. There’s some decent info that was used when researching this article.
Decks.com advice on pressure washing your deck is more in-depth and includes specific details on pressure and risks of damaging wood.