Spruce Lumber: Smooth, White and Straight

If we had to describe spruce in one word, it would be smooth. Spruce trees grow extremely straight, and the lumber comes out white, clean and nearly free of pitch. It finishes super smooth, it is very versatile, and it is a great choice for paneling, tongue and groove and paint grade work.

Size it up for timbers

Spruce is not as strong as Douglas fir, so we size it up for structural work. Where a 4x4 would carry the load in fir, use a 6x6 in spruce, and so on up the line. Most people like the look of the bigger timber anyway. Lab data puts our spruce about even with ponderosa pine in bending strength and stiffness, with fir ahead of both. However you build with it, attach posts to beams positively, with a mortise and tenon, a plate or something similar.

Flat and predictable

Spruce dries flat, and we always know what to expect out of it. We once kiln dried a 1x28, milled at about 15/16 of an inch, and it stayed flat. It also dries faster than fir. Now and then we have some really good circle sawn spruce in the yard, too.

What to watch for

Spruce from closer to the Continental Divide can carry some spiral in the grain, so the sawyer pays attention to which pieces become posts and which become beams. Posts with the heart still in them will check toward the heart, as nearly every wood does. We also run into a fair amount of rot in spruce logs, and good spruce logs are always the hardest for us to get, so ask early if your project depends on it.

Where it does not belong

Spruce is too soft for floors and countertops. In our experience it is also the first of our three softwoods to rot when it sits in the ground, so keep it up off the dirt.

One more thing, for the record: a green spruce log is Justin’s favorite to peel by hand. It works like butter. Fir is a lot harder on the shoulders.