Wood Finishing #1: Varnish vs Polyurethane
Varnish vs. Polyurethane Before we dig into the details, let’s talk about why we need different finishes for outdoor applications. Any wood that is used outside is going to be exposed to a wide range of climate conditions, as well as a good dose of damaging UV rays. These elements serve to break down the finish over time. Furthermore, changes in humidity cause the wood to expand and contract, and a standard indoor finish (such as polyurethane) would simply crack and deteriorate under these conditions. And this could result in a whole host of unnecessary repairs. Spar varnishes are typically designed to not only protect the wood but also give it the flexibility and UV protection it ...
