Our kitchen cabinets suffer from water damage, and I have refinished the doors more than once. I have been using Helmsman Polyurethane and each time the damage to the doors beneath the sink recurs. What is the best finish for wood doors that are exposed to ongoing water exposure? – Keith Smith
Chris Marshall: If a wood finish works on a boat hull, it’ll surely stand up to a sometimes-wet cabinet door, too. So, I think spar urethane like Helmsman is probably your best choice. It doesn’t cure as hard as other varnishes, which allows it to remain more flexible as the wood moves so it doesn’t crack. It’s those micro cracks that allow moisture to seep behind the surface film and begin to degrade both the bond of the finish and the wood surface. Not sure why your finish is continuing to degrade. Is the wood thoroughly dry–and not just “feels dry” on the surface but dry through and through? Moisture inside the cabinet door parts could be to blame. If the wood is topcoated but then releases the moisture inside, the finish will fail. You might want to check the doors with a probe-type moisture meter to see. If the wood turns out to be internally dry, try a new can of Helmsman. Maybe the vintage of your urethane is to blame.
But, the root of the problem here isn’t a failing finish, Keith. Sounds like you need to remedy why water is repeatedly getting into the sink base in the first place. Is it time for fresh caulk around the sink instead? Fix the source of the leak and you’ll be able to use any water-resistant finish you like under your sink. Even better, you won’t have to keep refinishing these cabinet doors–which can’t be fun. You’ll finally be able to check this problem off the project list for good.
Rob Johnstone: I am curious about the timing — how often do you need to refinish these doors? If you are doing it more than, say, every 5 years or so, I think I would need to agree with Chris that your biggest challenge is that you’ve got too much water messing with them. (Perhaps you have teenagers doing the dishes … in that case, I understand completely.) Helmsman is a fine product. Just follow the directions and you will have a solid finish that should really stand up to water well.