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How to clean decking with a pressure washer: Smarten up your wooden decking ready for spring

man cleaning decking with pressure washer outside how to clean decking with a pressure washer

Blast away winter moss, mould and muck from your decking with our expert pressure washing tips

Knowing how to clean decking with a pressure washer can save hours of back-breaking work scrubbing in the garden as you prepare for spring. Decking provides an attractive space for relaxing and entertaining during the warmer months, but like a patio, it does require some level of maintenance to keep it in good condition.

Algae, leaves, mould and moss can all accumulate over winter, causing wooden decking to become slippery and unsafe – not to mention scruffy-looking. The best pressure washers make quick work of sprucing up decking that’s dirty, but using one incorrectly could damage your deck and even cause serious injury.

The good news is that cleaning decking with a pressure washer is fairly straightforward. By following a few basic guidelines and a bit of practice, you can achieve great results, before moving on to other home and garden cleaning tasks.

From tackling tricky corners to using the right attachments and cleaning products, there are a number of things you need to know to become a pressure washing pro. In this handy explainer, we offer everything you need to know, as well as step-by-step instructions on how to best tackle your decking with a pressure washer.

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How to clean decking with a pressure washer

What is a pressure washer?

A pressure washer is a tool that pressurises water using an electric pump or petrol power into a powerful jet stream that can clear all manner of muck from various surfaces. Using a pressure washer will save you from hours of manual scrubbing, with tools such as the popular Kärcher range of pressure washers capable of handling everything from shower screens to patios, bikes and barbecues, and of course, decking.

Is my decking suitable for pressure washing?

To answer this you’ll need to know what type of wood from which your decking is made. Hardwoods such as oak, teak and bamboo are durable enough to withstand pressure washing using a wash brush head or spray nozzle. Woods such as beech, cedar, pine, spruce and other softer woods are not suitable for pressure washing and are best cleaned manually.

When should I clean my decking?

Decking is best cleaned in early spring to restore the wood to its former glory following the stresses of winter. Hopefully, the warmer and drier weather at this time will enable it to dry out and leave it looking its best.

What will I need?

How do I prepare my decking for pressure washing?

Start by clearing the decked area of garden furniture, equipment and plant pots, then sweep away any loose debris such as leaves, mud and grass clippings. With this done, you’re ready to get to work.

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How to clean your decking with a pressure washer step-by-step

1. Put on all protective clothing and equipment.

2. Connect your pressure washer to the hose or tap. If using a hose, ensure the reel is fully unwound and check the water can flow freely.

3. Connect your pressure washer to a safe, outdoor grounded power supply (unless using a cordless pressure washer) and turn on to pressurise the unit.

4. Attach the washer attachment (or spray nozzle) to the pressure washer and fill with detergent according to manufacturer’s instructions if using. Some washers or detergents will state that the product should be applied directly to the decking before pressure washing with water, so be sure to check the instructions.

5. Test your water pressure in an inconspicuous area. Pull the trigger while using the lowest possible pressure at least six inches away from the decking and holding at an angle of 45-degrees to direct any spray and debris away from you.

6. Increase the pressure gradually in increments until you find the best setting then start cleaning by using a wide sweeping motion following the direction of the wood grain.

7. Deal with corners by spraying into the corner and making an L-shape outwards.

8. Once you finished, flush the washer through to get rid of any detergent.

9. If sealing or staining your deck, you’ll need to wait two to three days (weather dependent) for the deck to dry out completely before you can do so.

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Don’t…

  • Use the direct jet of a pressure washer to clean decking – A direct jet is too abrasive and can make wood brittle or even cause it to split.
  • Use vinegar or other acidic treatments to clean your decking – Soda crystals or soft soap can be used if you need something extra, but purpose-made decking cleaner detergent will usually do the trick.
  • Spray too long in one spot – This can damage the wood and will give a patchy finish.
  • Direct the pressure jet at people, plants or pets – Pressure washers can cause serious injury.

The best pressure washers you can buy in 2024

A pressure washer can revolutionise your home and garden maintenance, saving hours of manual cleaning while delivering an impressive and professional finish. The best pressure washers come with a range of attachments for use around the home; but if you’re in the market for a new model with your decking in mind then do look out for a model with a washer nozzle and a pressure rating of around 120 bar. Read on for our pick of the best pressure washers for the job, according to our expert testing panel.

1. Kärcher K4 Power Control: Best all-round pressure washer

Price when reviewed: £240 | Check price at Amazon

karcher k4 power control pressure washer how to clean decking with a pressure washer

The newer, shinier version of the K4 Full Control from Kärcher, the K4 Power Control is as good as you would expect from the brand. Ideally suited to decking, its soft, flat jet spray pattern setting will clear off winter detritus without damaging your wood. There’s also some serious jet power available should you have a patio or drive that requires cleaning, too. There are three different pressure settings and a range of spray patterns to clear grime from all sorts of surfaces, particularly when you add in its Power Control Gun and Power Control Vario lance to its arsenal. A car and home kit is available for an extra £180, if you’re interested in tougher power washing jobs.

Read our full Kärcher K4 Power Control review

Key specs – Size: 40.2 x 30.6 x 58.8cm (WDH); Weight: 11.5kg; Max pressure: 130 bar; Water flow rate: Max 420l/hr; Hose length: 8m; Cable length: 5m; Cleaning area: 30m² per hour; Motor power: 1,800W


2. Kärcher K2 Compact: Best mini pressure washer

Price when reviewed: £130 | Check price at Amazon

karcher k2 compact yellow how to clean decking with a pressure washer

Another unit from Kärcher, this is the brand’s mini version; it’s portable, affordable and easy to manoeuvre and store. This machine has all the power you need for basic garden jobs and is gentle enough for use on decking – you should note that it would struggle with heavy-duty patio cleaning for anything over general lichen and algae removal. This is a hand-held unit and doesn’t have wheels, but since it weighs just over 4kg with accessories, it’s comfortable to use for short periods. There’s no detergent sprayer with this kit, but there is a syphon tube that you can insert into your decking cleaning solution. It’s also compatible with all of Kärcher’s range of pressure washer accessories. A word of warning: it’s quite noisy in use.

Key specs – Size: 18 x 22 x 39cm (WHL); Weight: 3.7kg; Max pressure: 110 bar; Water flow rate: 360l/hr; Hose length: 4m; Cable length: 5m; Cleaning area: N/A; Motor power: 1,400W


3. Halfords PW20: Best value pressure washer

Price when reviewed: £75 | Check price at Halfords 

halfords pw20 pressure washer in blue how to clean your decking with a pressure washer

The Halfords PW20 washer is a really good budget option, and it comes with a few extras you might not expect for such a small sum. First, it’s a good-quality machine: it’s sturdy and well built, with a decent 1,600W motor that manages to be quieter than that of the mini Kärcher. You’ll also find a handy adjustable fan nozzle for the lance, a foam bottle and a 5m hose with fittings; none of which are always a given, even with pricier models. We found it a doddle to use, the lower pressure (115 bar) means the job may take a little longer than higher bar pressure washers, though. The PW20’s 115 bar is perfectly sufficient for clearing the usual garden muck off your decking and patios, plus we found it useful for clearing brake dust from alloys too. A surprisingly good value washer.

Key specs – Size: 25 x 27 x 69cm (WDH); Weight: 6.3kg; Max pressure: 115 bar; Water flow rate: 300l/hr; Hose length: 5m; Cable length: 5m; Cleaning area: N/A; Motor power: 1,600W

Check price at Halfords

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