Woodworking Tips - Lumber Lingo

Understanding Lumber Terminology

If you are fortunate enough to have a hardwood lumber yard near you, you are in luck. You potentially have access to all kinds of wood species of different width, lengths and shapes; maybe even access to some live edge slabs! However, buying lumber can seem confusing and intimidating if you have never done it before or are not familiar with some of the terminology and lingo. In today’s blog, I want to spend a few minutes giving some tips on how to get yourself educated before going in to buy lumber so that you can have an understanding of some of the questions to ask, and what the folks at the mill may be asking you.

Types of Lumber

When it comes to buying lumber, you have two main categories, rough cut and dimensional. Rough cut lumber is wood that is straight off of the wood mill and has not been processed any further, meaning it has not been surfaced in any way. Rough cut, or rough sawn, lumber is very raw and is mainly for those consumers that are going to dimension the lumber themselves; either by hand or with machines. Even with rough cut lumber, you can purchase some partially dimensioned, or surfaced, lumber. This brings us to the next set of terms to know; Surfaced on one side (S1S) and Surfaced on two sides (S2S). Each of these means exactly what the name implies. S1S is rough cut lumber that has then been surface planed on one side and S2S implies that it has been surfaced on both  sides; the top and bottom faces. You can also, usually, get the boards surfaced on one edge, or both edges (S4S), surfaced on four sides. With rough cut lumber, the more surfacing you have the mill do, the more expensive the board is going to cost. Most lumber yards will charge you some price per linear foot (how long the board is), say and additional $.20 per linear foot.  Now, these boards may all still be of varying widths, so they are not uniform as is the case with dimensional lumber.

Dimensional lumber refers to lumber that is cut in standardized, uniform width and thicknesses; think pine 2x4 or 2x6 for example. Dimensional lumber has been surfaced and processed to conform to these regulated standards and are most often found in construction grade woods for house and framing, like the big box stores offer. On a cost basis, dimensional lumber costs more than rough cut lumber does, per board foot. “What’s a board foot?” you may be asking...

How Rough Cut Lumber is Measured

Rough cut lumber is priced and sold on what is called a board foot basis. Think of this as the volume of a piece of wood; width, times length, times thickness. There are a lot of calculators online to figure this out, but you can also do it yourself pretty quickly. For example, let’s say you have a 1” thick board that is 6” wide and 72” long. Your calculation would be: (1x6x72) which equals 432 cubic inches. To convert that to board feet, just divide by 144 and you are left with 3. So, that board equals 3 board feet.

Now, we need to take a minute to talk about one last thing; quarters. See, when you by dimensional lumber, you may already know that a “2x4” isn’t really 2” by 4”, but is actually 1.5” by 3.5”. Rough cut lumber works differently and is all based on quarters, which is the thickness of the rough, unfinished surface. So, you have 4/4, which is 1” thick; 5/4, which is 1.25” thick and so on, 6/4, 8/4, 12/4. This is important because that quarter inch is what is generally milled away to give you your final, finished dimension. For example, once you surface and mill a 4/4 piece of lumber, it’s optimal finished thickness will be .75” or 3/4 of an inch. So, if you are building a table and want to have a top on it that is 1” thick, you would buy 5/4 lumber and mill it to 1”.

Rough cut lumber of various quarters


So, as you are sketching out your next project and you are thinking “how much lumber do I need?” you can quickly break the pieces of the project into the their “quartered parts” meaning, “how many of my project pieces are made from 4/4?” or “how much 8/4 lumber do I need?” then, you can use that information to convert to board feet and then you will know about how much your project will cost in terms of wood required. This is extremely helpful in those situations when someone says “hey, how much would it cost for you to build me a coffee table?”. Now you can back your way into that number. Plus, hopefully when you go to the lumber yard, this has helped you understand the terminology they use and how they are calculating the cost of your lumber.

Any other tips or suggestions? Feel free to leave that in the feedback section!

Laying out parts on rough lumber