Deck and fence cleaning removes the grey weathering, algae and mildew from exterior timber and composite using low pressure and the right chemistry. On wood the goal is to lift the degraded surface layer without tearing into the soft grain beneath, which is a technique question rather than a machine question.
Why wood is unforgiving
Timber is not uniformly dense. Softwood decking has alternating hard and soft grain, and a pressure washer removes the soft portion far faster than the hard. Push too much pressure into it and you carve out the soft grain, leaving a permanently furred, splintery surface with visible wand marks.
Once that happens there is no washing it out. The fix is sanding, which on a full deck is a serious job.
The correct approach is chemistry first. A cleaning solution breaks down the grey oxidised layer and kills the mildew, then a low-pressure rinse carries it away. On badly weathered wood a brightening step follows, which restores the pH after cleaning and pulls the colour back toward fresh timber — that step also matters if you intend to stain, because stain applied over the wrong pH does not bond properly.
Composite decking is a different job
Trex, TimberTech and similar composites are not immune to pressure damage, and this trips up a lot of homeowners who assume the material is bulletproof.
Most composite manufacturers publish a maximum pressure and a minimum nozzle distance in their care guidance, and exceeding it damages the cap layer — often permanently, and often visibly as a lighter patch. Some warranties are affected.
Composite also grows mould in a way people do not expect, particularly in the embossed grain pattern and in shaded areas. It cleans up well with the right solution and gentle pressure. Tell us what you have when you call; composite and timber get quoted differently because they are genuinely different work.
Fences
Fencing is mostly a question of linear footage and how many sides. Cleaning one side of a hundred-foot run is half the job of cleaning both.
Wood privacy fencing responds much like decking — chemistry first, low pressure, optional brightening. Vinyl fencing cleans easily and mainly needs algae and green film removed from the shaded faces. Chain link is generally not worth washing unless there is something specific on it.
Fence posts at grade are where rot starts. If we see soft posts we will tell you, because cleaning a fence that needs replacing is money you would rather not spend.
What deck and fence cleaning costs
Decks are priced by square footage plus rails, spindles and steps — the vertical detail is where the labour actually goes. A deck with a hundred spindles takes far longer than its floor area suggests.
Fencing is priced by linear foot and by whether you want one side or both.
The real value is usually in what comes next. A cleaned deck is the necessary preparation for staining or sealing, and doing them as a sequence — clean, dry, coat — is both cheaper and better than treating them as separate projects months apart.
When to clean, and when to stain
Late spring and early autumn are the workable windows. Wood needs to dry thoroughly before any coating goes on, which means a run of dry weather and moderate temperatures.
Practical sequence: clean, allow roughly forty-eight hours of dry weather, then stain. Coating damp wood traps moisture underneath and the finish fails early.
Most decks want cleaning annually and re-coating every two to three years depending on exposure. A deck in full sun degrades its finish faster than one that is shaded.
Go Deeper