How to Pressure Wash Decking

If your decking is looking a little bit worse-for-wear, it may be time to liven it up. If it’s just a little bit of dirt and grime, you can probably get away with a stiff brush and some warm soapy water. However, for deeper cleaning, you’ll need to make sure you have the right tool for the job.

Using a pressure washer is a great way to clean your decking but it’s important that you have the right tools and technique. Pressure washers can be very powerful which means you’ll need to use a lower pressure on wood decking to avoid damaging the material.

So, whether your decking has had a lot of use in the summer, or it’s taken a beating from the winter weather, we’ve teamed up with Kimberley Walsh to show you how a pressure washer can leave your decking looking its best.

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Tools & materials

Pressure washer

You should clean your decking twice a year, preferably after summer and winter to improve appearance, prevent mould, and reduce the risk of slipping.
To clean decking using a pressure washer, you should first clear any furniture and debris. Then use a medium setting with a wide-spray nozzle to clean along the wood grain at a consistent speed, no less than 6 inches above the wood. Use a cleaning solution for best results. After, rinse with water, and let the decking fully dry before placing furniture back on top.

Why should I clean my decking?

There are a few reasons why you should keep your decking clean, with the most obvious being aesthetics, as you’ll avoid mould and harmful fungi from developing. Regularly cleaning your deck also helps to prevent the wood from becoming waterlogged, which can create slippery, dangerous spots on the surface.

It’s also important to ensure you pressure wash your decking before staining it to ensure it’s clear of all dirt and debris. This helps make sure you’re left with a smooth, consistent finish.

When should I clean decking?

It’s best to deep clean your decking around twice a year, once after the summer, and once after the winter. You’ll also want to make sure you avoid cleaning your deck in wet conditions, so the wood has a chance to properly dry afterwards.

How to pressure wash decking

To prepare your decking for pressure washing, first remove all furniture and planters, and use a stiff broom to clear away any loose dirt. It’s important to make sure you get into every nook and cranny of the deck, ensuring no debris is left behind. You can then use a leaf blower or garden vacuum to clear out any smaller pieces which may remain - you may want to use a dustpan and brush for smaller, more awkward areas.

You should also ensure that all outside sockets and other sensitive areas are covered before you use the pressure washer to avoid any damage.

If your decking is in a particularly bad state, you may need to apply a specialist wood cleaner. Let this soak for 5-10 minutes before rinsing it off with a hose or a low-powered setting on your pressure washer. Now your decking is ready for pressure washing.

Most pressure washers will come with a variety of attachments, and due to the soft nature of the wood, you’ll need one that creates a wider spray pattern. Usually this will be a fan nozzle or rotary attachment, often included with a pressure washer from brands like Kärcher.

These attachments increase the spread of the washer. Not only does this minimise damage to the wood, but it’ll also reduce the amount of time it takes to cover the whole decking.

Set your pressure washer to a medium power setting. You won’t want to use the highest power as this could damage the wood. If the decking is only lightly soiled, a lower power setting should be fine.

You’ll also need to put a wood-specific cleaning solution into your pressure washer. Some washers have a specific spot to place the bottle, and others will require you to submerge a pick-up hose in the bottle. Check the manufacturer’s instructions to see how your machine works.

Before you start cleaning your deck, it’s a good idea to make sure you’re prepared. To safely use a pressure washer, use safety goggles to avoid any debris spraying into your eyes. Also, when handling any cleaning solutions, you should wear gloves to protect your skin.

To get the best result when using a pressure washer, start by practising on an inconspicuous area of your decking, such as a corner usually be covered by furniture. This gives you a chance to work out what technique is best for your deck, ensuring you’ll get a consistent finish without leaving behind harsh cleaning lines.

When pressure washing a deck, you’ll want to hold the nozzle no closer than 6 inches from the wood to prevent damage. This should give you enough power to clean off tough dirt without stripping away the integrity of the wood.
You should work in straight lines, following the direction of the decking and the grain of the wood. Overlap your cleaning pattern to avoid creating water lines.
Keep your settings consistent throughout the cleaning process. If you increase or decrease the power mid-way, you may be left with an inconsistent result.
Keep moving. Stopping at one spot for too long can overload the wood with water, which can lead to damage.

When you’ve pressure-washed the whole deck, rinse it off with just water on the lowest spray setting to get rid of any loose debris or remaining soap before waiting for it to thoroughly dry. Once dry, it’s a great opportunity to spruce up your decking with paint or a treatment before putting back any furniture and accessories.

Cleaning your decking may seem like a big task, but when you have a pressure washer, it’s much easier and quicker than you’d think. Prep is an important part of the process before you use the high-powered jets to remove any tough stains.

It can also be a rewarding process watching the deck gradually get lighter, cleaner, and fresher as you move across it. Just make sure to keep it on a medium setting to prevent damage to the wood.

Looking to expand or renovate your decking? Check out our decking materials buying guide. Or, if your decking is just one surface which needs a good clean after a harsh winter, check out our guide for jet washing grime away from a variety of surfaces.

FAQs

If your decking is already damaged and splintering, you should avoid pressure washing as this will damage it further. In these instances, clean it with warm water, soap, and a sponge by hand.

You can use a pressure washer with just water and no cleaning solution. The high-pressure will remove some dirt, but without a cleaning solution, tougher stains and bacteria may not be removed properly.

Yes, you can pressure wash composite decking; however, you should only use a low power setting and a wide fan-tip nozzle to avoid damaging the boards.

After pressure washing your decking, you should wait around 48 hours for the deck to be completely dry before you begin to stain the deck.