A relative of mine wanted to know what finish is best to use on an outdoor oak bench he intended to make. Was it spar varnish, or is there something better?
First, to address the wood. He didn’t say what type of oak he intended to use, so I pointed out that white oak would be better than red oak for outdoors because white oak would hold up pretty well without a finish. Teak would be even better; it would hold up without a finish for decades, at a minimum. Many other “jungle” woods would also, but most are very hard and difficult to work.
Concerning the finish, I assumed the bench was going to be exposed to sun and rain all year round, in which case, no finish will hold up for more than
a few years because there won’t be a way to keep water from getting underneath and causing the finish (or paint) to peel. You can’t caulk a bench like you do the framing around windows.
Best Finishes for Outdoors
If he insists on applying a finish, maybe for looks or to make the surface smoother, a boat varnish from a marina would be best because it would hold up better against the sun’s UV light. Common brands include Interlux, Epifanes, Pettit and Z-Spar. They can be bought from Amazon. But they will still peel when water gets underneath.
The question of what finish to use on exterior wood is a common one. I’ve written about this in many articles and in all three of my books. Nevertheless, the question still comes up often. I think it’s because there is no shortage of exaggerated claims, from manufacturers, in magazine articles, in books, and from one friend to another. So lots of people continue to believe there must be a magical product out there somewhere, even though their experience tells them otherwise.
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