Redwood lumber is available in over 30 different grades. With such a variety, you can be sure to find a grade of redwood for almost any application suitable for wood. Redwood is graded by two important factors: appearance and durability. Redwood grading criteria are defined by the Redwood Inspection Service (RIS). For additional information about the grades and uses of redwood lumber, please read about Redwood Heartwood Grades and Redwood Sapwood Grades. You may also download the helpful Grades & Uses brochure from the California Redwood Association (CRA).
The Scotia Series™
For generations of deck-building contractors and do-it-yourselfers, the go-to grades of redwood Deck Common and Deck Heart came from Scotia, California and were known for their consistency in quality, board-sizing, and grading. Those same standards are the inspiration and benchmark for the Humboldt Redwood Scotia Series.
Excellence of appearance is a major factor in the grading of redwood. Freedom from knots, or clearness, is the determinant for the highest grades. Other grades are categorized by the number, size, and nature of knots as well as the presence of other characteristics such as stains or manufacturing defects that may occur.
Redwood is also graded for durability and resistance against insects and decay – factors easily distinguished by redwood’s color. Reddish-brown heartwood from the inner portion of the tree contains extractives that render it resistant to insects and decay. As a general rule, 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 – Clear All Heart, Heart B, Deck Heart, Construction Heart or Merchantable Heart.
The cream-colored sapwood that develops in the outer growth layer of the tree does not possess heartwood’s resistance to decay and insects. For construction above ground where there is little danger of damage from insects or decay, choose one of the sapwood grades – Clear, B Grade, Deck Common, Construction Common or Merchantable.
Architectural grades of redwood include Clear All Heart, Clear, Heart Clear, Heart B and B Grade. Normally sold kiln dried (pre-shrunk and stress free), these grades are for the finest exterior and interior architectural uses. These finish grades are unrivaled in beauty and dimensional stability. They are the preferred grades for siding, paneling, trim and cabinetry where beauty and tight joinery are desired.
Garden grades of redwood include Deck Heart, Construction Heart, Deck Common, Construction Common, Merchantable Heart, and Merchantable. These grades may be offered seasoned or unseasoned. They are frequently specified for exterior and garden structures where knots or other characteristics have little or no effect.