Pressure treated lumber is the most widely used building material when constructing for outdoor exposure. Ensuring its longevity is both financially and aesthetically important. Since moisture, sunlight and oxygen all work to degrade the wood, it makes application of the proper preservative coating essential to your treated lumber projects. To protect against moisture and harmful UV rays, an effective preservative surface coating must include some type of pigment (sometimes natural in color) along with a long-term moisture barrier that still allows the wood cells to breath naturally. This type of pro- tection is necessary in climates all around the world — from vertical walls and fences to walking sur- faces (decks, docks & steps) to handrails . . . and even the fresh end-cuts made during construction. The end cuts of treated lumber are too often overlooked during construction, but doing so can lead to problems with water damage. When dimensional lumber products are treated, they’re impregnated with a copper preservative that is forced by pressure into the wood cells, but the preservative doesn’t achieve 100-percent penetration.
“Even though lumber has been pressure treated, it is important to realize the treatment does not penetrate entirely through the wood,” says Jeff Wilson, Residential/Industrial Sales & Service Manager for Lonza, a world leader and innovator in the wood preservation industry. “So when a homeowner or con- tractor cuts the wood, they wind up with fresh end-cuts where the center area has less preservative than on the outer part of the wood. This is where applying a copper-based end-cut solution helps to prevent mold or decay. Sealing a project when complete is also very important to the longevity of the lumber used, but this initial coating of fresh cuts is instrumental to effective protection of a project.” The American Wood Protection Association (AWPA) has now made this recommendation official. According to AWPA Standard M-4: “When wood is pressure-treated with preservatives, it is absorbed in varying amounts by the sap- wood, but only a small amount of preservative penetrates the heartwood, juvenile wood, and some of the wood surrounding knots. Therefore, all drilled holes and cut ends need to be treated with a preservative, such as copper naphthenate or oxine copper (mostly for exterior use) or a boron-based preservative (for interior uses only).” In fact, the cut ends of lumber absorb rot-causing water at a much greater rate than the sides
Covering your Cuts when
Applying wood sealer to the end cuts of treated wood is more important than ever. Here’s why.
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