Ins and Outs of Roughsawn Lumber

Ins and Outs of Roughsawn Lumber

Many hardwood lumberyards stock “roughsawn” lumber. And just as the term suggests, the board faces and edges will be pretty rough. That’s because while the lumber will be kiln- or air-dried and ready for woodworking, it hasn’t been planed and joined smooth and flat. What you’re buying are boards in the state they were in when they were originally cut from the log and dried. The upside to roughsawn lumber is that it’s generally more economically priced than if it were pre-surfaced smooth and flat. Less processing by a mill means lower unit cost to them — and ultimately to you.

Two samples of rough sawn walnut boards
Dark outer surfaces on the walnut sample, might be hiding lighter sapwood areas underneath.

A downside to buying “in the rough” is that these boards haven’t been corrected for natural defects that often occur during the drying process. Some amount of bowing, cupping, twisting and checking are likely — and either you’ll need to correct for it with your shop machines or the lumberyard might do it for you for a fee.

What Lies Beneath?

Maple rough sawn lumber that has been lightly planned
“Skip planing” will reveal at least some of the actual figure and color you can expect. This maple board attests to it here.

With some species, it can be very difficult to tell what the grain pattern and color of a board is under that rough exterior. The murky, dark-colored top layer of walnut and cherry in particular can mask lighter sapwood areas. If grain pattern and color consistency is important to your project, ask the yard if they are willing to “skip plane” it for you. This light planing pass will reveal at least some of the board’s characteristics, which can help. You’ll pay a nominal extra fee for skip planing.

Ash lumber that has been labeled by quarter thickness
Roughsawn lumber is shelved and sold by its quartered thickness. Here, 8/4 ash (about 2″ thick) will have a fi nished thickness of about 1-3/4″, and 5/4 ash (about 1-1/4″ thick) will plane down to about 1″ smooth.

Roughsawn lumber has a quartered thickness, such as 4/4, 5/4, 6/4, 8/4, 12/4 and 16/4. Expect to see a wide range of widths and lengths, too — that’s the advantage of selling by volume instead of by “1x” or “2x” standardized lumber sizing. It’s sold volumetrically in “board feet” instead of a “per foot” price.

Woodshop Widget iPhone app output screen
The “Woodshop Widget” mobile device app makes quick work of board foot and price calculations.

So you’ll need to know how to calculate each board for the number of board feet it contains (where one board foot equals a piece 1″ thick x 12″ wide x 12″ long). But if math isn’t your strong suit, mobile device apps such as “The Woodshop Widget” can tabulate it instantly. An app like this can be a big help!

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