Can I Pressure Wash Treated Wood?

Treated wood is in many places, but it is mainly used to build wooden decks. Can you pressure wash treated wood without damaging it?

Treated wood can be easily cleaned with a pressure washer. To avoid damaging the wood, use a 40-degree nozzle, and keep it two feet away from the wood while cleaning it. If needed, move the nozzle closer to the treated wood to remove the tougher stains.

It is very easy to pressure wash treated wood if you know how to do it correctly.

How to Pressure Wash Treated Wood

Before you begin pressure washing treated wood, check what type of wood it is. Softwoods such as southern yellow pine will likely be damaged if you use a pressure washer to clean them (Source). However, even if you are pressure washing softer woods, you can avoid damaging them if you hold the nozzle far enough away.

Use the 40-degree nozzle tip so you don’t put any unnecessary pressure on the wood that may cause it to become damaged. The detergent and pressure from the 40-degree nozzle tip should be enough, even for the tough stains.

Remember to keep the nozzle moving at all times to avoid damaging the wood, even if it is not a soft type of wood. Any wood can become damaged by a pressure washer.

Pressure washing treated wood may not be necessary. Many decks are treated with a solution that prevents deep stains that would require pressure washing.

If you do not have a pressure washer, but want to clean your deck made of treated wood, soak your deck in soapy water and use a mop. This will clean off most of the dirt and grime.

However, using a pressure washer rather than a mop to clean treated wood will save you a lot of time and hassle, especially if there is a lot of grime and build-up.

Here is a list of step-by-step instructions on how to clean treated wood:

  • Remove anything that is hanging from the wood to prevent damaging the items. Remove any furniture from the area that you intend to clean.
  • Sweep away loose dirt, debris, and leaves.
  • Attach the soap nozzle to the pressure washer if you are choosing to use detergent. If you are not using detergent, attach the 40-degree nozzle.
  • Hold the end of the nozzle 2 feet away from the wood.
  • Move the nozzle in a straight, sweeping motion until the entire area is cleaned to your satisfaction. Redo any spots with deep stains if necessary.

Optional Last Step: Stain and seal the wood. The pressure washer likely removed the sealant on the wood and some of the stain color. This is a great time to change the color of the wood’s stain if you are planning on changing it in the future.

What Kind of Pressure Washer Should I Use?

There are four different types of pressure washers. They are hot water electric, cold water electric, hot water gas, and cold water gas pressure washers.

The hot water pressure washer is the best kind of pressure washer to use to clean treated wood. Cold water pressure washers do not remove grime as well as hot water ones. It is up to you if you want to use an electric or gas-powered pressure washer since the cleaning ability of both types of pressure washers is the same.

Both types can be rented at your local hardware store if you do not want to purchase a pressure washer, and the hardware store will likely offer both types of pressure washers.

If you are planning on purchasing a pressure washer to use in the future, the hot water electric pressure washers tend to be slightly cheaper than the other types, depending on the brand and size of the pressure washer.

What Type of Cleaner Should I Use?

While using detergent with your pressure washer will help you deep clean treated wood, it is not necessary. Wood is a porous material, and many treated woods are treated with stain-resisting materials, which eliminates much of the need for a cleaning detergent paired with a pressure washer. The pressure washer can get the job done with or without the cleaning detergent.

If you do choose to use a detergent, avoid using bleach-based cleaners. “Bleach-based cleaners have been found to cause harm to wood cells,” which will cause the wood to wear out faster than it should (Source). The bleach-based cleaners can also harm nearby plants because of the harsh chemicals included.

Oxygenated cleaners are an alternative to the bleach-based cleaner. However, oxygenated cleaners are trickier to deal with than many pre-mixed cleaners. Many oxygenated cleaners are powdered concentrates that need to be mixed with warm water and only stay active for half an hour, so you’ll want to make sure you get your work done quickly.

Other detergents are formulated to specifically be used with pressure washers. In my opinion, they are the best kind to use. They can easily be found in any hardware store. Use a gentle detergent that is designed to clean wooden surfaces. They range in price from around $10-$25, which makes them very budget-friendly.

Safety Tips

Safety is important to remember while using a pressure washer. If the water touches your skin while the washer is running, you can become seriously injured. Make sure that any children or animals are inside or away from where the pressure washer is being used.

What to wear while using a pressure washer:

  • Wear long, durable pants that cover your ankles. Jeans work fantastically.
  • Durable boots. Preferably waterproof.
  • Safety goggles.

After you finish pressure washing the treated wood, be sure to sand and seal it, even if it was already sealed before you washed it. If you pressure wash your deck, don’t walk on it with bare feet until you’ve re-sanded and resealed it.

According to Consumer Reports, “After a deep power washing, the wood fibers of the various components of the deck often raise as they expand with water. Once dry, these wood fibers can often remain raised and may cause splinters. For this reason, you should plan on sanding your wood deck after power washing and before staining and sealing” (Source).

After you have finished prepping your deck for use, enjoy your clean deck that looks like it is new!

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