How Do You Clean a Deck Without Wrecking the Wood?
A deck cleans at roughly 500–1,200 PSI with a wide fan tip kept moving — not the 3,000 PSI a driveway takes. Higher pressure tears the soft summer grain out from between the harder rings, leaving a furry, splintered surface and permanent stripes that no stain will hide.
Why does pressure washing ruin some decks and not others?
Wood is not uniform. Every board has soft, fast-grown summer wood between harder winter rings, and a high-pressure jet strips the soft part out first. The result is the fuzzy, raised, splintery surface people describe as the deck having gone furry after washing — that is torn grain, and sanding is the only fix.
Composite behaves differently but is not immune. Full pressure etches the embossed grain pattern off the surface and can leave a permanently shiny track where the wand lingered. Composite manufacturers are specific about this in their warranty language, which is worth reading before anyone points a machine at it.
What pressure is actually safe on a deck?
| Deck surface | Working pressure | Notes |
|---|---|---|
| Softwood (pine, cedar) | 500–800 PSI | Most Shoals decks — tears easily, stay low |
| Hardwood (ipe, cumaru) | 800–1,200 PSI | Denser, tolerates a little more |
| Composite / PVC | Soft wash preferred | Etches and gloss-marks under pressure |
| Painted or sealed wood | Soft wash preferred | Pressure lifts the finish unevenly |
What makes a Shoals deck go green in the first place?
Shade and humidity. A deck under tree cover in north Alabama never fully dries between rains, and that standing dampness grows the same algae and mildew that streak siding and roofs here. North-facing decks and the boards nearest the treeline always go first — that is the tell that you are looking at biological growth rather than dirt.
This matters for method, because growth does not respond to force the way ground-in dirt does. Blasting green off a deck removes what you can see and leaves the roots in the grain, which is why a pressure-only cleaning often looks green again within a season. Treating it chemically at low pressure is what makes the result last.
Should I seal the deck after cleaning it?
If the deck is bare wood, yes — and the timing matters more than the product. The wood needs to dry properly first, usually a couple of clear days in our humidity, because sealing damp wood traps the moisture underneath and the finish fails early. Sealing a deck that still has growth in the grain seals the growth in with it.
That sequence is the real argument for cleaning it properly rather than quickly. Deck and fence work falls under pressure washing, from $299, priced by square footage and surface — and a deck that was cleaned at the right pressure and dried out is the one where the stain actually lasts the three or four years it promises.
Questions we hear about this
Can I pressure wash my own deck?
You can, if you rent a machine with an adjustable regulator, fit a 25- or 40-degree tip, start around 500 PSI on an out-of-the-way board, and keep the wand moving and a consistent distance off the wood. The damage happens when a fixed-pressure machine meets a narrow tip and a pause in one spot — that mark is permanent.
How much does deck cleaning cost in the Shoals?
Deck cleaning is priced under pressure washing, which starts from $299 and is quoted by square footage, surface type, and condition. We price your exact deck at the walk-round, in writing.
Will cleaning remove the old stain from my deck?
A proper cleaning removes failing, flaking stain but will not strip a sound finish, and it is not a substitute for stripping if you are changing colors. If you want the deck taken back to bare wood, say so when you book — that is a different job with a different prep.
How often should a deck be cleaned in Alabama?
Once a year for most Shoals decks, usually in spring once the pollen has finished. Decks under heavy shade or near the treeline often need it annually without fail, because they never dry out enough to slow the algae down on their own.