DO FINISHES PROTECT WOOD AGAINST DECAY?
No. But a well-maintained coating helps keep moisture out of the wood, which in turn reduces the chance of decay. Unfortunately, painted wood is typically not well-maintained, and this can lead to trouble. Water that gets through cracks in a damaged paint layer will wet the wood, which can have trouble drying out through the paint. If water vapour trying to escape can’t easily get through the paint, it will break the bond between the paint and the wood, causing the paint to blister. Meanwhile, if the wood remains too wet for too long it can become an inviting environment for decay – decay may be hard to detect if the paint is hiding the damage. Bottom line: with or without a finish, you should use a durable wood product outdoors.
