5 Tips for Buying Lumber

Every woodworking project requires a certain amount of lumber. Unless you have a genie to procure that stock for you—or you're fortunate enough to have a stack of it on hand already—you're going to need to find and buy it. Rockler carries a wide selection of lumber in our stores and online, and so do specialty lumberyards, home centers and smaller independent sawmills. But buying the right amount of usable hardwood lumber for a price you can afford requires a little know-how, so you can complete your project without running short or ending up with far more boards than you really need. If you are new to the process of lumber buying, here are five tips that can help.

1. Always Start with a Material List

A well-thought-out plan for what you're planning to build does more than just give you a roadmap for how to make and assemble the parts. It also provides you with a good "ballpark" for how much lumber the project will require. In published woodworking plans, lumber is tallied up on a material list (such as the one shown below). Also commonly called a cutting list, bill of materials or a schedule of materials, it's simply a listing of all the parts that are necessary to construct a project. In today's terms, it's a spreadsheet that allows you to harvest the parts in the quantity and sizes you'll need. This information can be derived from multiple sources: a measured or scaled drawing, a mocked-up project or an existing piece of furniture.

At a minimum, a material list describes every part in terms of its thickness, width and length. Those measurements also include the length or width of a part's tenons or tongues, etc., within the specified dimensions. This list provides exact measurements of the completed pieces. No additional material is included as a "safety net" in case you make a mistake during the building process. Your lumber shopping list needs to account for every part specified on the material list. Even the most basic material list is essential—whether you're building from scratch or a published plan. It will keep you efficient, accurate and better able to buy an appropriate amount of lumber for the project at hand.

2. Learn How to Calculate Board Feet

Hardwood lumber is usually sold by the lineal foot in a home center, where the widths and thicknesses of a given size of lumber are uniform. So, the cost per foot multiplied by the length of the board sets its price. Specialty woodworking stores, lumberyards and sawmills, however, sell lumber by the "board foot" (BF) instead. That's because woodworking lumber often is left in random widths, lengths and thicknesses from the mill to maximize its potential yield. To account for this variation in sizing, BF is a way of tabulating boards volumetrically rather than by the "per foot" price.

But have no fear—this measurement system really isn't difficult to learn! Think of one board foot of lumber as 1'' thick, 12'' wide and 12'' long (essentially 144 square inches of 1''-thick lumber). The formula for determining the BF of any specific piece of lumber is Thickness x Width x Length divided by 144, whatever those first two numbers happen to be. So, a 1''-thick board, 6'' wide and 36'' long is 1.5BF (1 x 6 x 36 / 144). Use .5 instead of 1 for calculating board feet for 1/2''-thick stock, 1.5 for 1-1/2''-thick stock, and so on. Lumber that's pre-surfaced to 3/4'' is considered 1'' when calculating board footage, because it originally was derived from 1''-thick material before surfacing.

If math isn't your strong suit, there are free mobile device apps that can tabulate board footage for you. They also let you enter the listed price per board foot and instantly know what the board's cost will be before tax is applied. A mobile app can be a huge help at the lumberyard to keep track of your costs, so you won't be surprised at check-out time!

3. Know Your Surfacing Options

Hardwood lumber may be surfaced smooth to various degrees, as you'll find at Rockler stores. Or it may be left completely rough on its faces and edges, which is typical at specialty yards and sawmills. When boards are pre-surfaced, these four letter/number codes will let you know what degree of surfacing has been done to them:

S2S (Surfaced 2 Sides) – S2S boards are planed so their top and bottom faces are smooth and parallel. Both long edges are left rough and may include sapwood or tree bark. These rough edges can be desirable if you're looking for irregular edges to decorate a shelf, cutting board, jewelry box lid, etc.

S3S (Surfaced 3 Sides) – S3S boards have planed, parallel faces and one edge that has been straight-line ripped so it's perpendicular to the faces. The fourth edge is left rough. Here, you'll have a ready-made flat edge that you can feed along a table saw or band saw fence to cut the rough edge off, if you choose.

S4S (Surfaced 4 Sides) – S4S boards have planed, parallel faces and parallel, square edges. S4S is what you'll find at most home centers (see image below). The more surfacing a mill has already done for you before you buy it, the higher the cost will be. So S4S lumber generally will cost slightly more than S2S lumber. But the added expense may be a fair tradeoff if you don't have access to a planer or jointer to do the surfacing work yourself.

Be aware that even S4S boards my not be perfect. Boards can still distort after surfacing. They also will be planed to final thickness. If your S4S board is warped in some way, you may need to joint and plane it thinner to fix the problem. Will the thinner result still work for the project parts you need?

4. Roughsawn Can Be Your Diamond in the Rough

Alternately, there's also roughsawn lumber (see above). Its faces will be approximately parallel but otherwise unsurfaced, and both edges are rough and out of square. With this minimal level of surfacing, roughsawn is the most economical option for hardwood lumber. It can be an exceptional value, but you won't have a good idea of what the lumber looks like beneath those rough surfaces until you run them over your jointer and through the planer. So, you're assuming more risk for the savings. However, some lumberyards will "skip plane" boards at your request so you can inspect the face grain more clearly. Skip planing is simply a light surfacing pass that will remove some of the rough surface on one face, which can be helpful. Be aware that you may have to pay a nominal extra fee for this service.

Roughsawn lumber is milled to a quartered thickness, such as 4/4 (read "four quarter"), 5/4, 6/4, 8/4, 12/4 and 16/4. 4/4 lumber is roughly 1" thick—four quarter inches. So, 5/4 is about 1-1/4'' thick, 6/4 is approximately 1-1/2'' thick, and so on. With any rough lumber thickness, the rule of thumb is to subtract 1/4'' from the quartered thickness to determine what your "finished" stock thickness will be after surfacing.

5.Buy More Lumber Than You Need

We all know that mistakes can happen during the building process. Having some extra lumber on hand can help you keep working when you must occasionally re-make a part. Boards may present some unfortunate surprises too. For instance, you might rip a piece of lumber only to find that internal stresses in the wood cause the ripped piece to twist or bow unexpectedly, rendering it useless. Plan for these situations too. A good rule of thumb is to add 20 to 30 percent more to your estimate for waste (defects, poor grain pattern, building mistakes and so forth). If your project requires 10BF, buy 13 BF instead. It's always smart to have a bit of extra lumber on hand, and experience will prove the truth of it.