Do It Yourself: Lumber Grades Explained

Different lumber grades are used for different purposes depending on the project at hand. Some useful background terminology is provided so future purchases of lumber can be done as painlessly as possible.

Commercial lumber grades for the most part can be broken down to a basic range that should tell you everything that you need to know in order to purchase the quality you need for the project at hand.

To put the various grades in perspective, it might be helpful to have some grounding in certain lumber terms that are taken into account when grading lumber. Wane is a bark-like build-up on the size of a piece of lumber. It is literally where a tree branched off. Wane does not really become a factor, providing the surface affected will not be exposed. Wane becomes a factor when where the lumber will be nailed will be affected. Splits are as the name implies; small cracks that can splinter and break off, usually located at the end of the lumber. Knots are also obviously a factor used when grading and selecting lumber. Edge knots are much worse than center knots since they are more likely to affect the structural capabilities of the lumber. A particular worrisome form of a knot is the spike knot. This is a knot that can appear at first glance to be a very small knot, but in fact, extends through the lumber to the other edge. A 2x4 piece of lumber with a spike knot can break with one good whack. Spike knots can often be missed in the initial grading process, and you should look for them when purchasing lumber from a home center. Twists are literally how much warp there is in a board.

Economy is the lowest grade available. This is usually junk wood, dunnage taken off of railcars, and pencil stock. You can get a lot of twist, wane, and huge loose knots with economy grade lumber.

Utility is the next grade up in quality from economy. The discerning consumer can usually find a few useful pieces of lumber at this grade. One of the functions in large commercial lumberyards is buying utility grade lumber in bulk and upgrading it to "˜stud'

Stud grade, as implied by the name, is the most common grade used to build the framework of houses. Thus, the electronic device used to find lumber under drywall in a house is called a stud finder. Since the primary purpose of stud grade lumber is to hold up a house, very little twist is allowed, although you can have large amounts of wane and large knots.

A similar grade to stud is standard and better. The difference between the two is not so much in the size of the knots or the amount of splits or wane allowed, but in the fact that standard and better grade is used for lumber that is 12 feet and longer while the stud grade is used for 10 feet and 8 feet pieces in grading.

The next grade up in quality from stud and standard and better is 2 and better. This grade usually allows for smaller-sized knots and a minimum of wane and splits.

An even finer quality of wood is 1 and better. This is the crème de crème of lumber and should consist of small, sound and tight knots, only inches of splits, and practically zero wane.

Above 1 and better is select grade lumber. This is an even higher quality than 1 and can be used for high-end decorative purposes. Examples of this would be western red cedar, spruce shiplap, and tongue & groove wall paneling. Having mentioned that as an example, great effects can be had using lower quality cedar as paneling, incorporating its defects to achieve a western, weathered look.

Other facts about grading can be revealed by the grading stamp. The grading stamp will reveal what species the wood originated from. A grading stamp of DF refers to Douglas fir, while HF refers to hemlock fir. SPF is a generic grading stamp that can be used for spruce, pine or fir, but is usually used for spruce exclusively. A PP grading stamp can be used for ponderosa pine. Some consumers have a hard time telling pine and spruce apart when the generic stamp is used for both. One clear way to tell pine and spruce apart is that pine has a blue tinge to its white coloring. Another thing a grading stamp may reference is STK. This means that all knots on the lumber should be sound and tight, neither lending themselves to breakage or coming loose and turning into a hole.

Most home centers deal in higher end lumber since the consumer does not want to be bothered with the trouble of sorting too much. The lumber has been selected very highly before coming in the door. Most lumber suppliers to home centers have signed very specific contracts about the lumber they supply, and these suppliers take the contracts very seriously since so much business comes from the home centers. As always, the age- old adage "˜you get what you pay for' applies, though a discerning eye and a little background knowledge can be helpful as well. Good hunting!

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