Deck cleaning and maintenance

How do you clean a composite deck?

Sweep, then scrub with hot soapy water and a stiff bristle brush, and rinse. That’s Ekodeck’s instruction for Classic, and the other makers aren’t far off. ModWood says sweeping and household cleaners are usually adequate, and that sugar soap with water and a yard broom works well. NewTechWood suggests a monthly clean with water, mild detergent and a soft brush.

Can you pressure wash composite decking?

It depends on the maker, and two say no.

Futurewood’s source prints “8 kPa” and “1200 psi” together, and the two aren’t equivalent, so check its current care page before you set a washer.

Which deck cleaner works on composite?

The makers name specific products for specific jobs.

• Everyday dirt: sugar soap, or a composite cleaner such as Aqualis Composite Bright (ModWood) or Futurewood’s Composite Timber Cleaner, made by Aqualis Coatings.
• Mould: Wet and Forget, which ModWood says is slow and takes several months, or Aqualis Composite Bright with Aqualis No Fungal Pro used together. Futurewood warns that many harsh household mould cleaners can damage composite boards.
• Grease and sunscreen: a water-diluted degreaser such as Kenco, which ModWood says will lighten the pigment, so test it first. Both ModWood and Futurewood recommend a mat under the barbecue.
• Pool chemicals: wash off highly corrosive spills straight away (Futurewood) and keep undiluted chlorine and pool salt off the boards (NewTechWood).

Why are there brown stains on new composite decking?

Tannins. ModWood says tannin water stains appear in the early weeks as tannins leave the wood fibres, and they generally disappear with rain and weathering. Futurewood says residual tannin leaches out the first few times the board gets wet and shows as a stain once it dries, then fades after several wet and dry cycles. Colour softens over time: Futurewood says 4 to 12 weeks, ModWood says the final silver or grey arrives 2 to 3 months after installation.

Can you sand or seal composite decking?

You can sand scratches on Ekodeck Classic with 40 grit along the grain. Ekodeck says not to paint, stain or seal it. NewTechWood recommends a clear sealant on cut ends only. Static can build up on co-extruded boards in low humidity, which NewTechWood says isn’t covered by warranty and an anti-static spray reduces.

How do you clean a timber deck?

Timber decks take a different routine: a cleaner, a scrub and then oil. Two Australian channels filmed the process on merbau.

• Prep. New merbau is resinous, and untreated boards stain whatever is beneath them when it rains. One option is to let the deck weather in the rain for about four to six weeks. The other is a tannin-removing prep product: the first run-off comes out bright red, so put down a tarp and wear gloves and glasses, and don’t let the product dry on the boards. The painter leaves it about 15 minutes on a warm day.
• Clean. After prep, apply a diluted deck clean (one part to four in his case), leave 15 to 20 minutes, scrub and rinse until the water runs clear before oiling.
• Oil. A second presenter used a prep reviver to skip the usual wait of 6 to 8 weeks, then applied two coats on the deck and three on the steps, cutting in the edges before rolling.

Work in sections you can finish, and mark where you stopped so you don’t leave tide lines. These are their methods and figures, not maker instructions, so follow the label of whatever product you buy.

How do you maintain a deck year to year?

Sweep leaves and grit, clear the gaps, wash when it looks dirty and deal with spills the same day. Composite needs nothing more. Timber needs its finish renewed, and the only period we can put a number on is one presenter’s expectation of about 18 months from oil on a large merbau deck.