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.
Applying Pressure
Although highly effective for cleaning concrete, applying this much pressure to your deck can cause irreversible damage. To clean a deck effectively, about 1,500 pounds of pressure will do the job nicely, without causing permanent damage.
To clean a deck, some homeowners choose a washer with a pressure range of 1,300 to 2,400 psi, the same as washing a car. HGTV recommends working with the lowest pressure that cleans your deck materials gently: about 500 to 600 psi for soft woods like cedar or pine, and up to 1200 to 1500 psi for pressure-treated wood.
The pressure you need to wash your deck's surface can vary. Less is more when it comes to pressure washing wood or composite decks. For composite decks it's recommended that you can use up to a 3100 psi to pressure washer your deck. You only want to use enough pressure to remove embedded dirt and other contaminants.
Yes, a pressure washer will effectively remove deck staining. Use a pressure water rated for approximately 1,500 pounds per square inch (PSI) and position the nozzle at about a 30-degree angle, keeping it at least 3 inches away from the surface. But be careful.
Apply a cleaning solution
'Whilst you can use soap water, a specialist product such as Jeyes Patio and Decking Power is likely to be more effective to get rid of stubborn moss and algae,' says Sophie Herrmann, spokesperson for Jeyes Fluid. 'Mix it with water, pour it on and leave it to do its work.
If you have timber deck boards, a power washer's pressure may cause splintering and damage to the timber fibres. If the timber surface already has some splintering, pressure washing will only exacerbate the issue.
The short answer is 48 hours. You should wait at least two days after pressure washing your deck before you consider staining it, to give time for it to dry. Now let's talk about specifics. Cleaning your deck is an all-important first step in the staining process.
Treated pine decks don't last long when they're exposed to the weather. They split and crack and will need to be replaced within a couple of years. If you don't want the grey look and you want your deck to be protected, then yes… you should seal your deck after pressure washing.
Reach for the 1500 PSI Pressure Washer and use the 40-degree nozzle to clean painted soft-wood surfaces, aluminum siding, and windows. Brick, stone, and vinyl can handle the higher pressure of the 1600 PSI model. For stucco, stick to the gentler cleaning power of the WORX Hydroshot described below.
The larger your deck, the more frequently you should power wash it. For decks up to 500 square feet in size, it's usually recommended to be power washed once every year. For decks larger than 500 square feet, it's recommended to be power washed twice a year.
Concrete cleaning calls for powerful pressure washers featuring high pressure levels of 3000 PSI. However, if you will be using the power cleaner to maintain a range of surfaces in addition to concrete, choose one with adjustable pressure levels and set it to about 3000 PSI when you need to clean concrete.
Using a scrub brush is a low-cost option that is suitable for small decks and does not require any special equipment or training. Using a power washer is a quicker and more efficient method that is suitable for large decks or tough stains, but requires some knowledge and experience.
Sand the entire deck to remove any old stain, paint, or varnish from the wood. After sanding, power-wash the deck and allow it to dry for at least 24 hours before staining. Sanding exposes porous wood that's ready to soak up the stain, but this isn't possible if the wood is full of water.
2,000 to 3,000 PSI
Good for cleaning concrete surfaces with light to moderate oil stains, most automotive cleaning, pools, many industrial applications.
This looks like very small raised wood grain fibers or hair on the decking boards. When you are prepping a deck you essentially remove a layer of oxidized or damaged wood cells. The more you need to remove, the greater the chance of making the wood look “fuzzy” or “soft”.
The deck will need a minimum of 48 hours to dry after the cleaning. If it rains, wait two more days for the wood to dry. Avoid staining in high heat, high humidity and in direct sunlight.
When cleaning a cedar deck with just about any sort of cleaner, it's possible to end up with a white film often called "wood fuzzies" or furring. Furring can occur any time cedar is cleaned but is most seen in two scenarios: in new cedar or with heavily oxidized wood.
A deck cleaning solution is a great option to help remove tough, stuck-on oils and grime, though you can pressure wash a deck without it. If you opt for a deck cleaning solution, then you usually will mix the cleaner with water and pour the mixed cleaning solution into the dispenser on the pressure washer.
Your deck may not have grime on it, but the color of the stain may wear away. While you can apply a new layer of the stain without power washing, a pressure wash can help prepare the wood to absorb the stain. It will last longer afterward, and you won't have to worry about dirt getting stuck under the stain.
After you've pressure washed your deck, you'll need to wait for it to completely dry. Sometimes, this can take as long as 48-hours. Once it's dry, you'll want to sand your deck lightly. This is necessary to remove any splinters or fuzzy patches that pressure washing can cause.
Warm water can be used on its own to wash a wood or composite deck. Liquid dish soap (ammonia-free) is safe for use on cleaning your deck when mixed with a little warm water.