How to Clean Decking with a Pressure Washer

Pressure Washing a Deck

Cleaning your dirty deck is maybe something you’ve been putting off for a while, but if the garden hose is no longer getting the job done, it may be time to invest in some power.

Pressure washing is a cheap, energy-saving and efficient way to give your old deck a new lease of life. However, please proceed with caution and take some time to familiarize yourself with the equipment and always put safety first. Best practice with the pressure washer is to start on spots that it won’t matter if you damage them- an unseen corner of a deck is perfect for this. 

Now that the essential pitfalls have been pointed out, lets get into this in more detail.

Rent or Buy?

The first decision is whether to rent or purchase a pressure washer. If you rent one, the costs are reasonable and usually start at around $40 per day. That being said, if your deck is permanent and/or you have a lot of other household tasks lined up for a pressure washer, you’d be better off buying because pressure washers start at around $100 and are very inexpensive.

Setting Up Your Pressure Washer For Cleaning Decks

Once you get your pressure washer and you’ve practiced with it enough to be comfortable, you should decide on your pressure setting and what nozzle (or spray tip) you’ll need.

While it’s tempting to use a high-pressure setting such as 2,000 PSI (pounds per square inch), the truth is that wood simply doesn’t need that much pressure. In fact, if your deck is made out of softwood such as pine or cedar, you should stick with 500 to 600 PSI. Hardwoods can take a little more pressure, but you should still use no more than 1,200 PSI on those.

As far as your nozzle goes, you should use either a fan tip with a 40 to 60-degree spread or a rotating tip; however, the latter requires that you use it with caution and care. Even if the wood on your deck is hard, you should still start with 500 to 600 PSI and work up slowly from there. 

Each type of wood is different, and it’s always better to start with a low PSI and work up slowly to the number that’s right for you. While you’re at it, make sure you never spray any closer than six inches from the deck itself. If you spray closer than that, it can harm or damage the wood.

How to Use Your Pressure Washer

Pressure washers cause thousands of injuries each and every year, so preparing for cleaning your deck is just as important as the actual cleaning. Check out our article for more safety tips.

Make sure you wear long pants, shoes with good soles, and goggles. Remove jewelry and never wear loose clothing as you work with your pressure washer.
Most importantly, always follow the manufacturer’s instructions to the letter because the manufacturer knows more about your pressure washer than anyone else. Most of the accidents that occur each year could’ve been avoided by following these simple rules.

Next, prepare the deck itself, which means sweeping all debris off of it and clearing away anything sitting on the deck, including furniture or anything breakable. You’ll want your deck clear and clean before you start working with your pressure washer. If you choose to use a deck cleaner at this point, it can help to loosen up some of the stuck-on dirt, grime, and debris that’s there, and you can place this cleaner in the pressure washer itself. Feel free to add some cleaning detergent as well, whether you use a deck cleaner or not.

As you clean your deck, you should start at the house and clean the boards outward from there. Always work with the grain and spray lengthwise (parallel to the boards themselves) while slightly overlapping each area. After all, you don’t want to leave bare spots in the wood when you’re finished. When using the pressure washer, use a sweeping motion without pivoting with your arm. Move your arm back and forth laterally to get more consistency out of the job.

Keep in mind that while six inches is the closest you should get to the deck’s surface area, ideally, the wand should be about two feet from it. You can move a little closer when you need to remove stuck-on debris, but remember never to get too close to the deck or you can damage the wood. You should also consider using a stiff brush to work the cleaner between railings and into tight corners, and never let the detergent dry to prevent streaking.

Once the cleaning is complete, simply turn the pressure washer off and let the deck dry. 

Deck-washing is always best on hot summer days because that’s when the water dries the fastest. When the wood dries too slowly, the water might possibly seep into the wood and cause it to warp. While this usually doesn’t happen, it is still a possibility and therefore, you should only wash your deck on warmer and drier days.

Stainer or Brightener

Naturally, you should only mix up the solution according to the manufacturer’s instructions. After you apply the stripper/brightening solution, make sure you rinse it with plain water afterward. These products also tend to make the wood fibers a little on the rough side, which means that after you use them and before you re-stain or seal your wood, you should sand the deck completely first. 

Also, note that these strippers/brighteners are usually toxic to plants, so make sure you cover your plants and shrubs with plastic before you get started so that none of the solution gets on them.

Sanding Your Deck

The first thing you’ll want to do is wait until the deck is completely dry before you start sanding. The second thing you’ll want to do is use the right type of sandpaper.

Sanding not only smooths out the rough edges of the wood fiber, but it also opens up the wood’s pores so that the stain or sealer soaks up in a consistent manner.

Never use very fine sandpaper because it can actually clog the wood pores instead of opening them up. When sanding down the handrail, use sandpaper that is no finer than 100-grit. Use 60- to 80-grit sandpaper for the surface of the deck itself. You can either sand by hand or use a motorized sander with a 5-inch sanding pad. The latter is likely to be much easier on you, of course.

Are You Ready to Get Started?

Cleaning your deck with your pressure washer can be fun, but only if you take the precautions. You need to be safe while you’re working. Most experts recommend that you pressure-wash your deck once a year.

This way, it will remain in optimal condition for as long as you own it. Considering how fast and efficient using a pressure washer is, you can see that the return on your investment is quite high.

If you’ve never before done this type of job, it’s important that you pay attention to all of the tips mentioned in this article so that things go smoothly once you get started.

Most homeowners do well with a basic electric pressure washer, which typically accommodates up to around 2,300 PSI. This is more than enough power and pressure to get your wood deck super clean, especially if you remember to use the right nozzle, stay from six inches to two feet from the deck itself, and use no more than around 1,200 PSI – lower for softwoods. However, to avoid being a statistic and injuring yourself with your pressure washer,  use it according to the manufacturer’s recommendations and adhere to the right dress code.

Final Words

Pressure-washing your deck is a fulfilling experience and can make that deck look amazing. Once you get used to using a pressure washer, it isn’t tricky to do, so having one in your possession is always a good idea, especially once you realize everything you can do with it.