my Old Workshop

Green wood and green green wood

Calling wood “green” might cause a little confusion. Hope this clears it up.

When we talk about green wood, we don’t mean pressure treated wood, even through it often has a green tint to it. We’re talking about wood which came from a live, “green” tree with no drying. In fact, the log may have spent several months under water, floating down a river or stored in a log boom, where it soaked up even more water than it contained as a live tree. Then, as it dries, it twists and warps.

Occasionally, you’ll see the letters P.A.D. This stands for “partially air dried”. Take your chances with this one. “Kiln wets” is another scary classification. These are the rejects which did not meet specification. The lumber is usually a good grade, but the moisture content can be anything.

Unfortunately, much of the PT lumber being sold is green in more than one sense. It was green lumber before it was treated. This means it has all the twisting and warping problems associated with S-GRN white lumber plus it doesn’t retain as much of the CCA chemical. The chemicals are forced into the wood in a water solution, so if the wood is already full of water, it can’t soak up as much chemical.

Unfortunately, many people “shop the price”, so green PT is pretty common. Keep your eyes open. Paying a little more now may save you frustration and even more expense down the road.