Well that’s a tough one. It’s tough because there are so many different kinds of finishes and each one has a different cure time.

Drying Time of Oil Base Polyurethane

Let’s start with oil-base polyurethane. The short answer is about 30 days. But, there are a few more factors to consider for this finish. Like, are you adding stain first? How many coats of polyurethane are you going to apply? Are you using a sealer first?

Another thing to consider is the level of humidity during the drying period. Also, are finish coats being applied before the previous finish coat is completely dry? This can slow the process down considerably.

Drying Time of Waterborne Polyurethane

It’s so important to follow the manufacturer recommendations with waterborne polyurethane because there are wide variations among waterborne finishes. Some are oil modified. Some are cross linked, which is kind of like an epoxy. These generally cure up to 90 percent in the first 24 hours. Like I said, follow the manufacturer recommendations. You shouldn’t put on too many coats in one day or you’ll slow down the cure time.