Trex earns its reputation as low-maintenance decking, and it deserves it. You will never sand it, and you will never stain or seal it, and it shrugs off the rot, splinters, and yearly refinishing that a wood deck demands. But low-maintenance is not no-maintenance. A little regular care keeps the boards looking new and, just as important, keeps the warranty intact.
This guide walks through the whole routine: whether you can pressure wash (the question we get most), the simple twice-a-year clean, how to beat mold and specific stains, and the short list of things you should never do to a composite deck. If you have wondered why composite needs so little upkeep in the first place, the short version is the protective shell on modern boards, and most of the care here is about keeping that shell happy.
We maintain these decks all over Indianapolis, so we will flag the two local culprits behind most of the trouble here: heavy spring pollen that feeds mold on the shady side, and winter ice melt that can leave a residue. Handle those two and the rest is easy.
Can You Pressure Wash a Trex Deck?
Short answer: yes, if you have newer boards and you keep the pressure low. The real risk is not the dirt. It is using too much pressure and damaging the very surface you are trying to clean.
Start by knowing which boards you have. Trex’s newer capped lines (Transcend, Enhance, Select, and Signature) have a hard protective shell and can handle a careful wash. The older, uncapped products (Accents, Origins, and Contours) cannot, and pressure washing them fuzzes the surface and voids the warranty. Clean those by hand instead.
If your boards are capped and you want to use a washer, stay inside Trex’s limits:
- Stay under 3100 PSI. That is Trex’s ceiling, and about 1500 is plenty for routine dirt.
- Use a fan tip. A 40-degree fan nozzle spreads the force. Never use a turbo or pinpoint tip, which can gouge the board.
- Keep your distance. Hold the wand at least 8 inches off the surface.
- Soap first, then rinse. Spray soap, scrub gently with a soft brush along the grain, and rinse each board fully so no film dries on top.
Too close or too much pressure leaves permanent wand marks, and any damage caused by pressure washing is not covered. When in doubt, go gentler, or skip the washer entirely. Most decks never need one.
The Simple Cleaning Routine
Most of the time you do not need anything fancier than a hose, a brush, and some dish soap. Build two easy habits and the deck mostly stays clean on its own.
Day to day, sweep or blow off leaves and debris, and hose the deck down now and then. Pay attention to the grooves between the boards, because trapped debris holds moisture, and moisture is exactly what mold needs to get started.
Twice a year, in spring and fall, give it a proper wash:
- Clear the deck. Move the furniture and planters, and sweep off loose debris.
- Rinse. Wet the whole surface with a garden hose to loosen the dirt.
- Soap. Mix mild dish soap with warm water.
- Scrub with the grain. Work a soft-bristle brush along the grooves, not across them.
- Rinse thoroughly. Rinse every board until the water runs clear. If dirty water dries on the surface, it leaves a dull film.
That is the whole job. Twice a year clears the pollen and grime that would otherwise feed mold, which keeps the tougher cleaning below something you rarely have to do.
Getting Rid of Mold and Mildew
Mold is the most common complaint we hear, and it turns up in the usual places: the shady north side, spots under trees, and anywhere the deck stays damp. Here is the reassuring part. The mold is not eating your deck. It is feeding on the pollen, dust, and film sitting on top of the boards, which means keeping the surface clean is most of the battle.
For a light case, warm soapy water and a soft brush lift it right off. For a stubborn patch, a deck wash that contains sodium hypochlorite will clear it, but there is a catch: it can lighten the boards. Test it in a hidden corner first, use it only where you need it, and rinse well afterward.
Prevention beats scrubbing. Keep the grooves clear so water drains, trim back plants and branches to let in more sun and air, and stick to the twice-a-year clean. A dry, sunlit board rarely grows anything.
Removing Common Stains
Capped Trex resists stains and carries a stain warranty, but the trick with any stain is speed. The sooner you deal with it, the easier it lifts.
| Stain | What to do |
|---|---|
| Grease, oil, or food | Warm soapy water and a soft brush, as soon as you can. A grease-cutting dish soap helps. |
| Rust | Use a composite-safe rust remover, then rinse well. Keep metal tools and furniture feet off damp boards. |
| Hard-water spots | Wipe with a white vinegar and water solution, then rinse. |
| Ice-melt residue | Rinse it off with water in spring. Choose a calcium-chloride ice melt, not rock salt. |
| Fresh paint | Wipe it up right away with soapy water, before it dries. |
One rule ties all of these together: skip the harsh stuff. Acetone, paint thinner, and abrasive pads can break down the shell and the UV protection in the boards, which dulls the finish and can lead to fading later. Mild soap and a soft brush handle far more than people expect.
What You Should Never Do
A few habits will damage a Trex deck or void the warranty, and they are worth knowing, because some are things people do to wood decks out of instinct.
- Do not sand it. Sanding changes the surface and voids the warranty.
Do not seal or stain it. This is the big one. Capped composite never needs a sealer or a stain, and putting one on can leave a sticky film that peels and looks worse than the bare board. Skipping that chore is the whole point of composite, and it is the main way it beats the upkeep a wood deck demands.
- Do not use harsh solvents. Acetone and strong chemicals attack the protective shell.
- Do not use abrasive tools. Wire brushes and steel wool scratch the surface.
- Do not blast it with high pressure. No turbo nozzles, and no pressure washing older uncapped boards at all.
Winter Care in Indiana
Central Indiana winters add a season of care that warmer climates get to skip. The good news is that Trex handles cold, snow, and ice well. You just want to clear them without scratching the boards.
- Shovel with plastic. Use a plastic shovel, not a metal one, and push with the grain to avoid gouging.
- Choose your ice melt. Calcium-chloride ice melt is the safer pick. Avoid rock salt and colored ice melts, which can leave residue or staining. Rinse any residue off in spring.
Keep the gaps clear. Meltwater needs somewhere to go, so clear the grooves and the gaps between boards. That drainage is built into how the boards and gaps are built, and it only works when the channels are open.
A quick rinse once the weather warms clears off the winter’s salt and grit and gets the deck ready for spring.
Frequently Asked Questions
Can you pressure wash a Trex deck?
Yes, on newer capped boards, at under 3100 PSI with a fan tip held at least 8 inches away. Never pressure wash older uncapped Trex, because the pressure can permanently damage them.
What is the best cleaner for a Trex deck?
For everyday cleaning, use mild dish soap and warm water. Older uncapped boards do better with a composite-specific cleaner. For mold, a deck wash with sodium hypochlorite works but can lighten the boards, so spot-test it first.
Can you use bleach on Trex decking?
A deck wash containing sodium hypochlorite, which is a bleach, can clear stubborn mold, but it may lighten the surface. Test a hidden spot and rinse well. For routine cleaning, plain soap and water are safer.
Do you need to seal a Trex deck?
No. Capped composite never needs sealing or staining, and applying a sealer can leave a film that peels. Skip it entirely.
How do you remove mold from a Trex deck?
Soap, water, and a soft brush for light mold. For stubborn spots, a sodium-hypochlorite deck wash, spot-tested first. Then keep the grooves clear and let in sun to stop it coming back.
How do you get grease or oil off Trex?
Warm soapy water and a soft brush, as soon as you can. A grease-cutting dish soap makes it easier, and quick action keeps the stain from setting.
The Bottom Line
Trex asks very little of you: a sweep and a rinse now and then, a proper soap-and-water wash twice a year, and quick action on spills. Pressure wash only if you need to, and only low and careful. Never sand, and never seal. That short list is the whole maintenance plan, and it is a big reason how long a Trex deck lasts can be measured in decades rather than years.
The easiest way to stay ahead of it is to put two reminders on your calendar, one in spring and one in fall, and to keep the grooves between boards clear year-round. Do that and mold never gets a foothold.
On our Indianapolis decks, the two things that trip people up are spring pollen on the shady side and winter salt, and both take about ten minutes to handle. Stay on top of those, and the deck spends its life looking close to the day it was finished, with almost none of your weekends spent on it.