Can you pressure wash a deck?

It depends on the material. Wood decks can be pressure washed carefully — wide fan tip, at least 12 inches off the surface, along the grain — but a deck cleaner and soft brush usually do the job better. Composite decks are stricter: capped composite from the last decade can take up to 3,100 psi with a fan tip held at least 8 inches off the board, but early-generation or uncapped composite should never be pressure washed. When in doubt, use warm soapy water and a soft bristle brush, which is safe on both.

What is the best thing to clean a deck with?

For wood, an oxygen bleach deck cleaner (sodium percarbonate) is the standard — it brightens and kills organic growth without damaging wood fibers the way chlorine bleach does. For composite, mild dish soap and water with a soft bristle brush is the manufacturer-recommended routine. Avoid chlorine bleach on both: it damages wood fibers and permanently lightens composite caps.

How often should you clean a deck in Florida?

On the Gulf Coast, clean on a schedule rather than when it looks bad: a light soap-and-water pass after the spring pollen drop and again after the rainy season. Humidity keeps shaded decks damp most of the year, and salt air holds moisture against the surface, so organic growth returns faster here than the once-a-year schedule most national guides recommend.

How do I tell if my deck is wood or composite?

Check the end grain (wood shows grain lines; composite is more uniform or speckled), the fasteners (wood uses visible screws or nails; composite often uses hidden clips), and the temperature (composite runs cooler than wood in the same sun). If you still cannot tell, use warm soapy water and a soft brush, which is safe on both.

How to Clean a Deck on the Gulf Coast: Wood vs. Composite Decides Everything

The method that cleans a wood deck without ruining it is the method that will destroy a composite one, and vice versa. Before you buy a bottle or rent a machine, you need to know which material you are standing on — because on the Gulf Coast, getting it wrong is expensive.

The question that brings most people to this page is simple: my deck is green and dirty, how do I clean it? But the answer depends on a question most people never ask: what is the deck actually made of? On the Gulf Coast, where a wood deck and a composite deck can look identical from the driveway, that distinction is the difference between a clean deck and a ruined one. The method that works on one material will damage the other, and the damage is not subtle — it is a warped board, a bleached cap, or a surface that will not hold stain.

This page is the general deck guide. If you have composite decking specifically, our composite decking guide goes deeper on the capped-vs-uncapped decision and the pressure limits the manufacturers publish. This page is for the decision that comes first: what you are standing on, and what that means for the wash.

How to tell what your deck is made of

The material determines everything, so start here. Three quick checks:

Look at the end grain. Wood shows grain — lines, rings, the pattern of a tree. Composite shows a more uniform, sometimes speckled cross-section, and on capped boards the cut end reveals a thin shell around a darker core.
Check the fasteners. Wood decks are usually screwed or nailed with visible fasteners. Composite is often installed with hidden clips or specially coated screws, and the board spacing is more uniform.
Feel the temperature. On a hot day, composite runs cooler than wood because it does not absorb heat the same way. If the deck is noticeably cooler than the concrete next to it in the same sun, it is likely composite.

If you still cannot tell, the safe assumption is the one that works on both: warm soapy water, a soft bristle brush, and a garden hose. That method will not damage either material, and it is the right starting point for most decks in ordinary condition.

Cleaning a wood deck

Wood is the traditional deck material, and it is the one that tolerates — and often needs — more aggressive cleaning. The enemy on a Gulf Coast wood deck is not dirt. It is organic growth: algae, mildew, and mold that take hold in the grain and feed on the humidity. A wood deck that looks dirty is usually a wood deck that is alive.

The right method for wood:

Sweep and dry-brush first. Remove loose debris, pollen, and leaf litter. Everything you remove now is something you are not driving into the grain later.
Apply a deck cleaner. Use a cleaner formulated for wood decks — an oxygen bleach (sodium percarbonate) is the standard choice. It brightens the wood and kills organic growth without the damage that chlorine bleach causes to the wood fibers. Follow the label for dilution and dwell time.
Scrub with a soft brush. Work along the grain, not across it. The grain is where the growth lives, and scrubbing across it drives debris into the scratches.
Rinse thoroughly, top to bottom. A garden hose at moderate pressure is enough. The rinse carries away the dead growth and the cleaner residue — leaving residue is how a deck gets a white haze.
Let it dry completely before staining or sealing. Wood should be dry to the touch and have had at least 48 hours of dry weather before any finish goes on.

What about a pressure washer on wood? It is possible, but it is easy to get wrong. A pressure washer held too close or at the wrong angle raises the grain, leaves furrows, and opens the wood to moisture. If you use one, keep the wand at least 12 inches off the surface, use a wide fan tip, and work along the grain. For most wood decks, a deck cleaner and a soft brush do the job better and with less risk.

Cleaning a composite decking

Composite is sold as low-maintenance, and compared to wood it is — but the maintenance it does need is specific, and it is specific in ways the marketing does not explain. The surface is a wood-and-polymer composite, and on newer boards it is wrapped in a protective polymer cap. That cap is what a pressure washer endangers and what bleach attacks.

The right method for composite:

Sweep and remove debris. Composite does not absorb water the way wood does, but debris trapped on the surface holds moisture and feeds mildew in the grain texture.
Wash with warm soapy water. Mild dish soap and water, applied with a soft bristle brush, is the manufacturer-recommended routine for most composite. It removes surface dirt and organic film without attacking the cap.
Rinse thoroughly. Soap residue left on the surface attracts dirt and reads as a film. Rinse until the water runs clear.
Dry and inspect. Composite does not need staining or sealing, but it does benefit from a periodic inspection for mildew in the grain, especially on shaded or north-facing sections.

The pressure washer question for composite is the one people get wrong. Our composite decking guide covers the manufacturer limits in detail — the short version is that capped composite from the last decade can take a pressure washer up to 3,100 psi with a fan tip held at least eight inches off the board, while early-generation or uncapped composite should never see one. When in doubt, use soap and a brush.

The bleach question

Bleach is the instinct, and it is the wrong one for most decks. On wood, chlorine bleach damages the wood fibers and can leave a rough, raised surface. On composite, bleach attacks the cap — the protective shell that gives the board its color and stain resistance. The manufacturers are explicit: Trex states that products containing bleach or acid will lighten the surface, and the lightening is permanent and blotchy.

If you need to kill organic growth on a wood deck, use an oxygen bleach deck cleaner instead. It is effective on algae and mildew and does not damage the wood the way chlorine bleach does. On composite, the manufacturers' recommended cleaners are formulated for the material — not household bleach. The EPA's mold-cleanup guidance adds the two rules that decide whether the job is a clean or a replacement: act quickly, because mold damages what it grows on, and porous materials that become moldy may have to be thrown away.

What the Gulf Coast changes

Every interval on this coast is shorter than the national advice assumes, and a deck is no exception. Humidity keeps a shaded deck damp for most of the year, airborne salt settles on the surface and holds moisture against it, and the pollen drop delivers exactly the food source mildew feeds on. The practical translation is that on this coast you clean a deck on a schedule, not when it looks bad: a light soap-and-water pass after the pollen drop, and again after the rainy season, keeps the surface from becoming a long-term food source.

Two Gulf Coast specifics are worth stating. First, rinse thoroughly — more than you think is necessary. Hard, mineral-rich water left to dry on a deck leaves a film, and on a coast where the tap water is hard in many metros, a deck that was cleaned but not rinsed looks worse than before. Second, a deck on the water's edge is still at the mercy of salt; it does not rot like wood, but the salt film holds moisture against the surface and feeds organic growth, so the rinse and the schedule matter more here than inland.

When to call a pro

A ground-level deck in ordinary condition is a reasonable DIY job. What is worth paying for is narrower: a deck with heavy, set-in mildew that needs the right chemistry and dwell time, a two-story deck where the ladder work is the real cost, or a deck where someone is about to reach for a pressure washer on composite. Around Sarasota, Bradenton, Venice and Lakewood Ranch, the deck-cleaning crew we point homeowners to works both wood and composite at low pressure and can tell you which material you have before they start. Whoever you call, the question that sorts them in one answer is the one this whole page is built on: "What material is my deck, and does the method change if it is composite?" A crew that answers with a method and a word about the material has done this before. A crew that says "we blast everything" has told you everything you need to keep looking.