Why knots ooze sap on exterior applications

Knots on trees in the wilderness look interesting when they ooze sap — it’s natural. Odds are high you poked at one when you were a kid. When you climbed certain trees, they were sticky. Depending on the tree, most of the time, that sticky stuff is sap.

PINE means pitch or sap. It’s in there. If you use red pine for any project, you’ll have more sap; it’s part of the pine. Some species of pine, such as white pine, are better because they ooze much less sap.

In our experience, white pine performs the best, especially for exterior applications. We find red or Norway performs the worst for exterior applications because of the sap.

Some people don’t care which pine they use — especially when they are shopping with a price point in mind — so we offer both red and white pine. Most people don’t care until it’s excessive. Just be aware: You’ll have less maintenance with white pine than red pine when it comes to the sap issue. The choice is yours.

There are many other species of pine out there that are used as building materials. Buildings with even a small amount of red pine can have excessive oozing at knot spots. Even if only corners are done with red pine, that’s where you’ll find the most sap. It happened with some of our first tiny rustic cabins. The rest of the exteriors were white pine. We are slowly phasing out red pine even for trim and corners. Red pine is a beautiful species of wood because of its character so we continue to use it for interior applications. It’s one way we’ve improved what we have to offer from a sap-issue standpoint.

About 98 percent of people looking at wood won’t notice the difference between red and white pine on exterior applications once it’s stained. The only way you’ll be able to identify the species is by the amount of sap that appears.

You never should have the sap issue on the inside of a building. It’s the sun that makes knots ooze sap. It draws on the wood and pulls the sap out of it. Mother Nature does it. We can’t tell you which piece of red pine will ooze sap and which one won’t. It’s the nature of the pine. There’s nothing you can do about oozing knots — except clean them.

Using white pine nearly eliminates this issue. It’s like everything else: An investment in a quality product makes a difference. If you want to go with a high-quality wood product that has less maintenance than most, go with white pine. You’ll be glad you did.