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Is it safe to use a jet wash on your timber decking? And what about composite decks, do they require any special treatment? Once you've had your decking installed, follow these simple maintenance steps to ensure it lasts year after year. Prefer to speak to the professionals? We offer decking maintenance and repair services across Dorset - get a quote today.
Decking ServicesDecking takes more of a beating than most parts of your home. It’s exposed to rain, frost, sun, foot traffic, and whatever the garden throws at it year-round. Over time, dirt builds up, algae forms, and the surface can become slippery, tired-looking, or even start to deteriorate.
Knowing how to clean decking properly makes a big difference to how long it lasts, how safe it is to use, and how good it looks. At FMT Solutions, we regularly maintain, repair, and install decking, and we often see damage caused by well-meaning cleaning attempts that were simply too aggressive or poorly timed.
This guide walks through the right way to clean both wooden and composite decking, whether jet washing is a good idea, how to treat decking afterwards, and when it’s worth calling in professional help.
Decking isn’t just decorative. It’s a structural outdoor surface that needs regular care. When dirt and organic matter are left to build up, moisture gets trapped. That’s when problems start.
Poorly maintained decking can:
Regular, correct cleaning keeps decking safer underfoot and helps avoid costly repairs or replacement later on. It’s one of those home maintenance jobs everyone puts off, until it suddenly becomes unavoidable.
Before reaching for any cleaning product or pressure washer, it’s important to know what kind of decking you’re dealing with. The approach for timber and composite decking is very different.
Timber decking is porous. It absorbs moisture, which means it’s more vulnerable to:
Softwood and hardwood decks both need gentle handling and regular treatment to stay in good condition.
Composite decking is lower maintenance but not maintenance-free. While it doesn’t rot like wood, it can still:
Knowing how to clean composite decking correctly prevents surface damage and avoids voiding manufacturer warranties.
Cleaning wooden decking is about patience rather than force.
Remove furniture, pots, and planters. Sweep thoroughly to remove loose debris, leaves, and dirt.
Lightly wet the decking to prevent cleaning products soaking in too quickly.
Use a product designed specifically for timber decking. Avoid household bleach, which can weaken fibres and discolour wood.
Use a stiff-but-not-hard brush and scrub along the grain. The aim is to lift dirt, not strip the surface.
Rinse with clean water, ensuring no residue is left behind.
Decking must be completely dry before any treatment is applied.
This method protects the wood while still delivering a noticeable improvement.
Composite decking needs an even lighter touch.
Avoid abrasive tools or harsh chemicals. They can scratch the surface or cause uneven fading. Many composite manufacturers specify cleaning methods, and straying from these can invalidate warranties.
This is one of the most common questions we’re asked: can you jet wash decking?
The short answer is: sometimes, but carefully.
Jet washing can be effective if:
However, high pressure can:
For composite decking, jet washing is often discouraged altogether unless done at very low pressure.
Professionals use controlled cleaning methods that balance effectiveness with protection, particularly on large or high-value decks. Sometimes it's easier, and most cost-effective, to hire a decking maintenance service.
Cleaning alone isn’t enough for timber decking. Treatment is what protects it long-term.
Once fully dry, wooden decking should be treated with:
Treatment helps repel moisture, reduce UV damage, and slow down algae growth. Most timber decking benefits from treatment once a year, depending on exposure and usage.
Composite decking does not need oiling or sealing. Applying treatments designed for wood can actually damage the surface.
Knowing how you treat decking, and when not to, is key to avoiding unnecessary damage.
Over the years, we’ve seen the same issues crop up repeatedly:
These mistakes often lead to premature wear or expensive repairs.
As a general rule:
Decks in shaded or damp areas often need more frequent attention, especially where algae forms quickly.
Large decks, like the decking FMT Solutions built for The Pear at Parley in Ferndown, or commercial spaces require more robust maintenance schedules to keep them safe and presentable.
There’s nothing wrong with DIY cleaning, but there are times when professional help is the sensible option.
You may want to call in an expert if:
Professional cleaning is often combined with inspections, minor repairs, or upgrades. This saves you time and preventing future issues.
Decking often sits alongside other outdoor features like benches, seating, and joinery. Cleaning is also a good opportunity to assess whether your space is still working for you.
We regularly support clients with:
Gentle brushing with a decking-specific cleaner is the safest method for both timber and composite decking. Avoid harsh chemicals and excessive pressure.
Yes. High-pressure jet washing can damage timber fibres and shorten the lifespan of decking if not done correctly.
Algae should be removed using a suitable decking cleaner and gentle scrubbing. Regular cleaning prevents it returning quickly.
Warm water and a mild detergent are usually sufficient. Always follow manufacturer guidelines.
Timber decking typically benefits from annual treatment, though this can vary depending on exposure and usage.
Yes. Bleach, strong detergents, and abrasive cleaners can damage surfaces and strip protective layers.
Slippery decking increases the risk of slips and falls, particularly in damp conditions. Regular cleaning significantly improves safety.
Yes. Professional cleaning focuses on controlled methods that protect the material while delivering effective results.
Read more in our ultimate decking FAQs.
Knowing how to clean decking properly is one of the simplest ways to protect your outdoor space. Whether it’s timber or composite, the right approach prevents damage, improves safety, and keeps the deck looking its best.
For homeowners and businesses who want peace of mind (or who simply don’t want to risk getting it wrong) professional cleaning and maintenance offer a reliable, long-term solution. Contact FMT Solutions and get a quote for decking maintenance today.