A Buyer's Guide to Lumber
(Page 2 of 3)
July/August 1987
By the Mother Earth News editors
Softwood
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Softwood grades exist for both construction and remanufacture use. Lumber for remanufacture is supplied exclusively to industry and is divided into shop grades, industrial clears and specific product stock. Construction lumber is for consumer use and is broken down into three general categories:
Stress-graded includes typical framing members, and timbers, posts, decking and stair stringers. This "American Standard" lumber must meet the criteria of the National Grading Rule.
Nonstress-graded includes yard lumber and wood used for general building purposes, such as boards, battens, lath and planks. The boards are known as commons and are separated into five different grades depending upon the species and the lumber manufacturing association concerned. No. 1 grade has tight knots and minor blemishes and is used for paneling, shelving and finish work; No. 2 has larger knots and noticeable blemishes and is suitable for flooring and rustic paneling; No. 3 has knotholes and visible flaws and is good for sheathing and fencing; No. 4 is a low-quality board with adequate strength for subflooring and concrete forms; No. 5 is the lowest grade of board, used for crating because of its appearance and limited strength. Some species, such as Idaho (western) white pine, are graded by name (colonial, sterling, standard, utility and industrial), but because of differences in species characteristics, grade numbers and names are not always interchangeable.
Appearance lumber is nonstress-graded but is visually appealing and is suitable for working, shaping and fine finishing. Most appearance, or "select," grades are noted by letters and are separated into three categories. Grade B & Better allows only a few minor surface imperfections and is chosen for superlative finish work; C Select is the most readily available and has limited defects, which makes it suitable for quality trim and cabinetwork that use a natural finish; D has surface imperfections that can be covered with paint. A certain number of species are graded by number and description (1 and 2 clear) and others use names (prime, supreme, choice and quality).
