Q: My clients' 5-year-old composite decking is starting to fade, and they're starting to panic. What can I do to bring the decking back to life?
A: Jim Grant, the proprietor of Jim The Deck Guy, in San Diego, Calif., responds: Scorching sun, weeks of rain or snow, mold and mildew, and food stains can impact the appearance of any type of deck—composite decking included. Fortunately, most composite decking can be restored to look like new with a simple maintenance regimen, as long as the problem is on the surface and not in the substrate.
To clean a dirty composite deck, we mix up a batch of Duckback's Composite Deck Cleaner (superdeck.com) in a 5-gallon bucket. One 2.5-pound container costs around $30 and makes 5 gallons of cleaner, enough to clean about 125 square feet of decking. We use warm water and mix thoroughly; the cleaner is designed to work at a specific concentration, so we never add more water than the manufacturer recommends.
Depending on the size of the deck, we apply the solution with a garden sprayer or just a soft bristle brush dipped in the bucket. After the cleaner foams up, we scrub the decking with a medium-stiff bristle deck brush. To prevent the cleaner from drying out on the deck, we work on one small area at a time, keeping a garden hose close and misting the cleaning area frequently. Then we rinse the cleaned area with either a low-volume pressure washer or a strong stream from a garden hose. Most decks will require two applications of the cleaner.
In recent years, we've also been applying Duckback's clear acrylic sealer to decks after we clean them. The sealer prevents heavy dirt and stains from bonding to the decking, making it measurably easier to clean the next time. Any cleaner or protective sealer should always be tested on a small area first.
To prevent a severe build-up of dirt, which can be difficult to erase, I recommend cleaning composite decking every two years. In addition, I advise my clients to hose down their decks every month or so to keep the surface clean.