Q I installed an Eon deck around an aboveground pool in 2007. All the boards are peeling badly, and Eon is out of business. I thought this type of decking resisted peeling and fading. Is there a way to sand or scrape and then stain or paint the decking?
Shane O'Neill responds: Composite decking is supposed to resist peeling and fading, but how well it succeeds depends on the product and its installation, composition, and exposure.
The environment near a pool can be tough on a deck. Pool chemicals (chlorine, bromine, or salt) can accelerate damage, and sunlight reflected off the water can increase the surface temperature of the decking beyond what's anticipated by the manufacturer. (Low-e windows - designed to reflect the sun's energy instead of allowing it to pass through - can have a similar effect; a study by NAHB found that the reflection off low-e glass could heat a decking surface to over 200 degrees. Fiberon and Gossen, and perhaps other manufacturers, warn about this in their literature.)
Now that the damage is done, a few options are available to you. According to a conversation I had with a former Eon employee, Eon can typically be coated. Eon was pretty much the only product on the market made from polystyrene, but the same procedures recommended here can also be used on most traditional wood-plastic composites and cellular PVCs.
Wash and Sand First
Wash the decking and completely remove any grunge. If it's fairly clean to start with, hot water and liquid dish detergent will probably be adequate. If there's excessive build-up of dirt, use a composite-deck cleaner and follow the instructions. Let the surface dry fully.
To smooth the peeling areas, sand lightly along the length of the boards using 220-grit sandpaper. Don't go overboard. The idea is to knock off the loose stuff, not grind it down. Try a small spot in a corner first and if 220 grit is too aggressive, go to a smaller grit size. Don't use a belt sander, as it's hard to control and may grind too much off. You can use a random orbit sander to lightly work the surface; run it at a slow speed to avoid heating - and possibly melting - the material.
Once all the peeling material is removed, wash the deck again with hot water and liquid dish detergent to remove the sanding residue. Let it dry again. Do not use solvents - they may very well melt or dissolve the decking. If you've ever poured gasoline into a Styrofoam coffee cup, you know exactly what will happen.
Use High-Quality Paint
Paint the deck surface with a high-quality deck paint. There are several on the market that state they can be used on synthetic or composite surfaces.
Typically, the higher the solids content, the longer a coating will hold up. This usually corresponds with the price of the paint. Several paint manufacturers offer a texturing additive, which can provide traction in wet areas (nice around a pool). Follow the manufacturer's instructions on application, coverage, number of coats, and drying time, and use a non-shedding roller or a sprayer to make the job go quickly.
For types of decking other than Eon, start by checking the decking manufacturer's website for recommendations regarding coatings. Some companies offer suggestions, while others do not recommend any type of coating. Be aware that applying a coating will likely impact the warranty. If your cellular PVC manufacturer doesn't recommend a particular product, a paint formulated for use on vinyl, like VinylSafe from Sherwin-Williams (800/474-3794, sherwin-williams.com), may be an option.
Finding a durable coating that will stick to the surface of one of the new capstock composite products might be difficult. Most caps are polyethylene, one of the hardest polymers to bond coatings to. Any attempts to coat these should first be made on a scrap of material. You may find that several products will peel right off with almost no effort, so don't guess.
Shane O'Neill is the founder of Compositology, a consulting and testing firm specializing in composite building products. He can be emailed at email@example.com.