“Grade” refers to the appearance and durability of redwood lumber. Grades of redwood lumber are determined using criteria outlined by the Redwood Inspection Service (RIS). There is a grade of redwood for almost any application suitable for wood.
Appearance is the first, primary factor in the grading of redwood. Clearness (freedom from knots) is the determinant for the highest grades. Other grades are categorized by number, size, and nature of knots and the presence of other characteristics such as stains or manufacturing defects that may occur.
Durability is the second, primary factor in the grading of redwood. Durability against insects and decay is easy to identify by looking at the color of the wood itself. Reddish-brown heartwood from the inner portion of the tree contains extractives that render it naturally resistant to insects and decay. The cream-colored sapwood that develops in the outer growth layer of the tree (closest to the bark) does not possess heartwood’s resistance to decay and insects. As a rule of thumb, all heartwood grades of redwood will have the word “Heart” in the grade name.
For uses where the wood will be on or near soil, such as posts, bulkheads or patio grids, it’s essential to use one of the durable, heartwood grades. For construction above ground where there is little danger of damage from insects or decay, choose one of the sapwood grades. The most commonly available heartwood and sapwood grades are described below. Additional grades may be available via special order. Please inquire at the Pro Contractor Desk for information and product availability. You may also buy online (select states only) at HomeDepot.com.
REDWOOD HEARTWOOD GRADES
Heart B is an architectural grade characterized by limited knots and other slight imperfections. Available kiln dried or unseasoned. This grade can be surfaced or saw-textured. Uses of Heart B redwood include siding, paneling, trim, fascia, molding and other architectural uses. Quality decking, fencing, garden structures and other outdoor applications on or near the soil.
Construction Heart is a garden grade containing knots of varying sizes and other slight imperfections; available seasoned or unseasoned. This highly useful grade is available surfaced or rough. Uses of Construction Heart redwood include decks, fences, posts, retaining walls, garden structures, stairs or other outdoor applications on or near soil.
REDWOOD SAPWOOD GRADES
Quality grade containing sapwood, limited knots and other slight imperfections. Available kiln dried or unseasoned. This grade can be surfaced or saw-textured. Uses of B Grade redwood include siding, paneling, trim, fascia, molding and other architectural uses; quality decking, garden structures and other above-ground applications.
Same general characteristics as Construction Heart, but contains a combination of heartwood and sapwood. Unseasoned or seasoned, may be surfaced or rough. Uses of Construction Common redwood include deck boards, fence boards and other above-ground garden uses that do not require heartwood’s insect and decay resistance.