LUMBER : Oh, Wood That You Could Understand : Doing Homework and Learning the Lingo Can Make Shopping Easier and More Efficient
For some, the most harrowing part of a home project is buying the lumber. What kind of wood is best? What grade? What do they mean, seasoned? Why isn’t this 2-by-4 really 2 by 4?
In the good old days, you got your advice where you got your lumber--at a lumberyard--but few of them remain. In the ‘90s, even the pros get their lumber from Home Depot or HomeBase or home center/lumber outlets such as Ganahl Lumber Co., Buena Park Lumber Co. and Barr Lumber Co.
Both types of stores serve the non-professional, and the home center/lumber outlets have yardmen (people who handle the lumber) who can guide neophytes.
Even so, doing a little homework and learning lumber lingo can make shopping much easier.
Soft vs. Hard
Most likely, you are going to want softwood, the lumber that comes from evergreen, cone-bearing trees such as Douglas fir. Softwoods have high strength and an attractive grain, are easy to cut and nail and accept paint well. Almost all house framing is done with softwood lumber.
Hardwood comes from deciduous trees--those that drop their leaves in winter--and though it’s a good choice for woodworking projects, paneling, molding or cabinets that will be stained, it is much more expensive.
Incidentally, softwood is not always soft, and hardwood is not necessarily hard. Spongy, lightweight balsa is classified as a hardwood.
Measuring Up
Softwood is available as boards or as dimension lumber.
Boards--lumber less than 2 inches thick and more than 3 inches wide--are used where appearance is important. Softwood boards are good choices for shelves, furniture, porch flooring, molding and trim.
Dimension lumber is the workhorse breed, ranging from 2-by-2s through 4-by-18s. Used when strength or thickness is required, this lumber usually remains unseen as studs, structural light framing and structural joists and planks.
Lumber is described by its nominal dimensions, not its actual size. A 2-by-4 may measure 2 inches by 4 inches when it is sliced from a log, but it becomes smaller after it is dried and the surface planed to make it smooth. Because most softwood lumber is surfaced on all four sides (S4S), the 2-by-4 will actually measure about 1 1/2 inches by 3 1/2 inches. Even rough lumber, which is neither dried nor surfaced, may vary in measurement.
Drying Out
In lumber language, seasoning means drying. Softwood lumber is sold after various degrees of drying: green (that is, no seasoning), air dried or kiln dried.
Almost half the lumber sold in Southern California is green, as indicated by the marking S-GRN. Such lumber can be as much as 50% cheaper than seasoned lumber, but it is more prone to shrinking and warping as it dries naturally. It is frequently used for framing, according to John Timm, contractor sales representative at Barr Lumber Co. in Costa Mesa.
Softwood lumber sold for appearance is always dried, if only because it’s more attractive. Air drying, often called solar drying, and kiln drying are the two methods of seasoning lumber. The S-Dry (solar dried) or KD (kiln-dried) marking means the lumber had been dried to a moisture content (MC) of 19% or less at the time it was surfaced. MC-15 means the lumber was kiln-dried to a 15% maximum moisture content.
Type
Lumber sold locally comes from more than 15 western softwood species, and sellers often lump these species within marketing categories that sometimes overlap. There is a “Douglas fir” category, for example, but also a combined “Douglas fir-larch” category. “SPF” means the wood is from spruce, pine or fir trees. “Hemlock” includes hemlock and true firs. And the “western woods” category, in effect, includes them all.
Home centers often ignore market categories, labeling lumber simply as pine or white wood.
Grade
Most lumber has a grade stamped on it. This marking certifies that the lumber has been visually graded by experts certified by the American Lumber Standard Committee and manufactured according to U.S. Department of Commerce standards.
“Boards without a grade stamp are satisfactory for many projects, but grade-stamped lumber is required by the Uniform Building Code for all structural applications,” says Rich Geary, Southern California field representative for the Western Wood Products Assn. “Building inspectors will red-tag (halt) structural work done with lumber which does not have a grade mark.”
Boards are graded for appearance:
* Select--Top grade divided into three categories: B or Btr for ultimate quality, C for fine quality and D for good quality.
* Finish--The next grade, divided into “superior” for nearly clear (that is without knots or flaws), “prime” for slightly flawed and “E” for boards whose imperfections can be cut away.
* Common--Lower grade that includes knots. It is rated by numbers, from No. 1 for the highest quality to No. 5 for the lowest.
* Other grades--”Select merchantable,” “construction,” “standard,” “utility” and “economy” are meant for general use.
Dimension lumber is graded for strength:
* Select structural--Top grade, from No. 1 for highest quality to No. 3 for very good quality.
* Construction--Good appearance and strength.
* Standard--Good strength but less attractive.
* Utility--Strength at a savings.
* Economy--Many defects.
* Stud--Strength and size appropriate for studs.
To avoid marring the face of the highest grades, grade stamps are put on the back or end of the piece. Lesser grades carry the stamp on the face or front.
The grade stamp also tells the buyer the agency responsible for the grading, the species of wood, the degree of seasoning and information about the manufacturer.
Grain
Some pieces of lumber will be identified as “vertical grain” (VG), that is, parallel grain lines running the length of the piece, as contrasted with flat grain, which has a marbled appearance.
Although vertical grain has less tendency to warp, the pattern created by knots, crotches, pores and growth rings in the flat grain is attractive for some projects.
Clear boards, those with the fewest imperfections, come from the outer section of the log. The center section or heartwood has more knots.
Finger-jointed lumber is beginning to appear in the home center market. Technically a structural-glued lumber product, this lumber consists of numerous smaller sections joined together with special glues. Such lumber is certified for many uses, including studs and molding. Manufacturing techniques such as this enable mills to use nearly 100% of the tree.
Selection
After you decide on the type and size of lumber, it’s time to select it--piece by piece.
If measurement is crucial, carry a steel tape rule to check each piece. It’s not uncommon for lumber of the “same” size to be off by 1/16 or 1/32 of an inch.
Test for warping or distortion by lifting the end of each piece and sighting down the face and edges.
Look for knotholes, cracks, splits, hollows, chipped or missing edges and untrimmed bark. Tight knots are usually not a problem, but loose knots will fall out and leave holes. All of these characteristics are considered when the lumber is graded.
Lumber with stains, insect holes and sap oozing from below the surface may not be very attractive, but it may still be useful for your purpose. Check the grade stamp.
Avoid pieces where the grain pattern looks like a bull’s-eye. They were milled from the center of the log and have a greater tendency to twist and warp. If the ends are splintered or nicked, they will have to be trimmed, thus shortening the piece.
Informed and careful selection can keep costs down.
“If appearance is not important, you can save money by buying the lowest grade suitable for the job,” Geary says. “Utility grades give strength for the lowest cost.”
(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)
Sheets of Wood Information
The Western Wood Products Assn., the largest lumber manufacturers association in the United States, offers more than 100 books and pamphlets to help both homeowners and professional builders.
“Western Wood Species,” in two volumes with color photographs, is an encyclopedia of softwood species and grades. Other publications deal with ecology, basic wood selection and woodworking techniques. Project plans are also available, from patio decks to multistory buildings.
Information is available by writing to WWPA, 522 SW 5th Ave., Portland, OR 97204, or by calling (503) 224-3930.
(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)
LUMBER: HOW IT’S USED
Softwood is sold in boards or as dimension lumber. Boards are less than two inches thick, more than three inches wide and are used when appearance is important. Dimension lumber ranges from 2x2 through 4x18 and is used when strength and thickness count. Here are some examples of different uses for lumber and boards: * Shelving * Studs * Molding * Roof rafter * Trim * Paneling Framing * Deck board * Joists * Plywood sheathing * Handrail * Posts
BOARD LOGIC
Softwood lumber--sturdy, attractive and easy to cut, nail and paint--is ideal for many home projects. Before reaching retail outlets, lumber is inspected, graded and stamped with five symbols to denote species, moisture content and grade quality, among other things. A sample symbol pattern: WWP: Western Wood Products Assn. trademark to certify quality 12: Mill identification number STAND: Identifies best use of wood, others include CONST, STUD D FIR: Indicates Douglas fir species; spruce, cedar, pine are the other common species S-DRY: Indicates maximum 19% moisture content
COMMON WOOD DEFECTS Crook: Warped edge line; check by looking down face, edge Bow: Dip in the face Cup: Bends across the face Twist: Multiple bends Knots: Tight knots are OK; loose knots may fall out, leaving a hole Checks: Cracks along annual growth ring Split: Cracks running all the way through lumber Shakes: Hollow spaces between growth rings Wane: Edges or corners with untrimmed bark or wood missing
Sizing It Up
In lumber lingo, a 2x4 really isn’t. Here’s the translation of industry standards of frequently used lumber sizes, in inches: Nominal Actual: 1x2 and actual size: 3/4x1 1/2 Nominal Actual: 2x2 and actual size: 1 1/2x1 1/2 Nominal Actual: 2x4 and actual size: 1 1/2x3 1/2 Nominal Actual: 2x12 and actual size :1 1/2x11 1/4 Nominal Actual: 4x4 and actual size: 3 1/2x3 1/2
* Source: Western Wood Products Assn.
* Researched by CAROLINE LEMKE / Los Angeles Times