In the last few years at least three major coatings’ suppliers have introduced deck coatings that have failed often enough so they have generated a number of class-action lawsuits against the companies. You may have seen ads for these products: Behr Deckover, Olympic Rescue-It and Rust-Oleum Deck Restore. You may have even used one of these products.
When I first saw one of the ads, I knew exactly what was going to happen and the reasons for it. Each of these coatings is marketed to “restore” a badly grayed deck to an even coloring that is claimed to last for years. The coatings are thick and are applied thickly with a roller so there’s a significant build. That’s the problem.
Without getting into the lawsuits, which you can easily research for yourself online if you’re interested, here are the two most likely reasons these coatings fail.
First, coatings don’t bond well to grayed wood. The graying is caused by the sun and rain removing the surface lignin, which provides the wood’s coloring and glues the wood fibers together. So when it has been removed, the surface fibers aren’t bonded well to the wood underneath. You can often scrape off these fibers with your fingernail. Any film-building coating applied over these fibers is likely to peel because it isn’t bonded well to the healthy wood underneath.
Second, it’s not possible to keep water from getting underneath a film-building coating on a deck and causing the coating to peel. On areas of your house where siding butts up against a window or door frame, you apply caulk to prevent the penetration of water. You can’t do this successfully on a deck, nor would you want to try because it would be ugly.
So even though most of the commentaries I’ve read from people initiating these lawsuits claim to have cleaned and power washed their decks well, then allowed days for the wood to dry (in other words, followed instructions), the coating failed anyway.
No surprise to me.
What amazes me is that apparently no one at these three major companies could foresee what was going to happen.
Want to learn more about finishing from Bob Flexner?
Check out his book “Flexner on Finishing,” at shopwoodworking.com