Pressure-Washing a Deck

Get the expert knowledge you need for power washing a deck.

Pressure Washed Deck

Pressure Washed Deck

Woman walking on a clean deck that has been pressure washed.

Photo by: Jupiterimages

Jupiterimages

By: Sean McEvoy

Power washing a deck seems like a simple task. Just point and shoot, right? But the reality is that without the right equipment and knowledge, power washing your deck can potentially cause costly or even irreparable harm to the wood.

Choosing the right power washer and operating it at the correct pressure setting are the first keys to correctly power washing a deck. Power washers can be powerful enough to carve into brick or gentle enough to remove a few cobwebs.

Refinish Your Deck in a Weekend

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Refinishing a Deck

A deck can be a valued extension of the home, but time and the elements  will take their toll. If it has been a few years or even decades since your deck has been given the attention it deserves, it may be time to refinish with necessary repairs, a thorough cleaning and a fresh coat of paint or stain.

Photo By: Photo by Mick Telkamp

Determine Your Needs

A deck that is just a couple of years old or has received regular maintenance is still likely to benefit from a good cleaning. An older deck may need repairs to railings or steps, replacement of split or splintering planks and decisions will need to be made regarding the type of stain used to protect and beautify the structure.

Photo By: Photo by Mick Telkamp

Sweep and Assess

Clear any furniture or plants from the deck, grab a broom and clear off  surface debris. As you traverse the deck, make note of any split, splintered or rotting lumber, raised screws or nails, rusted hardware  and any other problems which will need to be addressed.

Photo By: Photo by Mick Telkamp

Select a Cleaning Solution

Diluted bleach is a popular choice for deck cleaning, but isn’t necessarily the best choice. Over time, stain is more likely to fade or discolor and bleach can hasten the degradation of the wood. Instead, select a cleaner formulated specifically for deck cleaning and follow manufacturer instructions regarding dilution and application.

Photo By: Photo by Mick Telkamp

Apply Cleaner

Deck cleaner can be spread by using a brush or broom to sweep across the surface or applied using an inexpensive tank sprayer as shown here. Make sure all edges, corners and gaps are treated as will as the deck surface. Follow manufacturer instructions regarding use, but in most cases, the solution should be left to soak on the wood for a period of time before continuing.

Photo By: Photo by Mick Telkamp

Pressure Washing

A pressure washer is a powerful tool for cleaning a deck. Take care to select a nozzle appropriate for the job. Spray nozzles are categorized by the angle of the spray. A zero degree “red tip” provides the most powerful stream, but can damage the soft wood. Consider a nozzle with a spray angle of 25 or even 40 degrees to clean your deck without scarring the surface.

Photo By: Photo by Mick Telkamp

Controlling the Spray

Hold the spray wand at an angle to push dirt and grime away from the contact point. Use consistent motion and distance for uniform cleaning without the risk of pitting or scarring.

Photo By: Photo by Mick Telkamp

Repeat Cleaning Process, If Necessary

If it has been a long time since the deck has been pressure washed or has been subject to unusual mildew or staining, a second application of deck cleaner and another round of pressure washing may be needed for a thorough cleaning. If you were on the fence about applying a new stain to the deck, it may be easier to decide once you’ve seen it at its cleanest.

Photo By: Photo by Mick Telkamp

Tap Down Exposed Nails

Wood shrinks over time and nails that were driven flush with the surface of the deck may need to be tapped down.

Photo By: Photo by Mick Telkamp

Replacing Planks

Planks that have cracked, split or rotted may need to be removed. Individual planks may be pried up and replaced with new lumber of the same type. Although a structurally sound choice, newer wood will not match older when using a clear sealer or a semi-transparent stain.

Photo By: Photo by Mick Telkamp

Selecting a Stain

If the lumber used to build your deck looks just perfect in condition and color, you may elect to apply a clear sealer. For most of us, the deck will benefit from a little color, but the choice of stain used will vary with preference and deck condition. A deck that is in good condition with minimal splintering and uniform color throughout is a good candidate for a semi-transparent stain, which soaks into the wood and leaves the grain of the wood visible. Solid stains, as we use on this project, coat the surface of the wood like paint and will hide replaced lumber and minor weathering. If the condition of the wood is especially weathered, a resurfacing stain containing grit is a forgiving choice and can hide cracks as deep as 1/4".

Photo By: Photo by Mick Telkamp

Apply Stain

Plan to stain once deck is completely dry and no rain is in the immediate forecast. Tape off edges as needed and make sure no debris is present. A paint pad or roller can be used to apply stain to the deck, but care should be taken to apply evenly. Solid stains are more forgiving, but uneven application or “touch up” spots will stand out when using semi-transparent stains.

Photo By: Photo by Mick Telkamp

Corner, Gaps and Railings

A paintbrush should be used in corners, railings and in gaps between planks. Railings and gaps between deck boards require special attention and can impact the amount of stain and time needed for the project.

Photo By: Photo by Mick Telkamp

Solid Stain

While the look of solid stains obscure wood grains, pitting, scarring and other indicators of age and use are hidden.

Photo By: Photo by Mick Telkamp

Leave an Escape Route

Apply stain from corner or wall to deck edge to allow an egress when finishing up.

Photo By: Photo by Mick Telkamp

Continued Maintenance

A yearly cleaning and inspection will keep the deck looking good, but expect to re-stain in anywhere from three to 10 years, depending on the type of stain used. Proper care and maintenance of your deck can drastically increase its lifespan with minimal expense.

Photo By: Photo by Mick Telkamp

For cleaning a wooden deck, you'll be best served by using the lowest pressure setting that's still effective. For soft woods like cedar or pine, this is usually about 500 to 600 psi. For harder woods, it can go up to 1200 to 1500 psi.

Choose the right tip to use as well. For wood cleaning, generally a fan tip or rotating tip (used carefully) will work best. Remember to always start the water pressure in a safe area pointing away from people and glass windows, and start at least two feet from the wood deck, then feather the pressure into range from about a foot to 18 inches from the deck. Never get closer than 12 inches from the deck unless you're using low pressure.

Remember to start in an area that would be easy to repair or replace. For example, try starting on a stair tread, which would be simpler to replace than an entire deck board. Once you're sure you've got the right pressure setting, work from the house outward and be sure to keep a consistent distance as you hold your arm steady and sweep, working with the grain of the wood. If the washing results in raised soft wood fibers, you will need to sand before staining your newly cleaned deck.

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