Lumber grading Rules

Lumber inspection and grade rules writing. WWPA is one of seven grading agencies in North America authorized to write and publish grading rules for lumber. The Association also conducts regular inspections at mills to assure consistent quality between mills. Each year, WWPA lumber inspectors check lumber representing some 10 billion board feet of production.

Western Red Cedar as insulation

Wood being a good insulator assists in keeping our homes cool during the summer and warm in the winter. Western Red Cedar is superior in its ability to resist thermal conductivity more than any other commonly available softwood. At 12% moisture content it has an R value of 1.35 per inch of thickness, which is 8 times better than concrete, 400 times better than steel, and 2,000 times that of aluminum.

Western Red Cedar Decking

Western Red Cedar (WRC) decking substantially outperformed composite decking in each of the seven criteria tested and was by far the product with the least environmental impact when compared with both virgin and recycled wood-plastic composite decking products.  Even after subjecting the cedar decking results to a ‘worst case’ scenario in which WRC required the replacement of 20% of boards in normal service and periodic application of coatings, the environmental impact results remained strongly favorable to Western Red Cedar over the ‘best case’ scenario for composite decking.

Western Red Cedar Lap Siding

Channel siding is a popular type of lap  siding and is used whenever a rustic appearance  is desired. A  versatile siding, it can be installed vertically, horizontally or diagonally.  In channel siding the profile of each board  partially overlaps that of the board next to it creating a channel that gives shadow line effects, provides excellent weather protection and allows for dimensional movement.

Cedar Bevel Siding

Western Red Cedar bevel siding is the most widely-used siding type. It is produced by resawing lumber at an angle to produce two pieces thicker on one edge than the other. The manufacturing process results in pieces with one face saw textured. The other face is smooth or saw textured depending on the grade and customer preference. Bevel siding is installed horizontally and gives an attractive shadow line which varies with the thickness of siding selected.

Cedar Siding Preparation

On the job site, keep wood dry. Stack siding off the ground and under cover. If the wood is to be stored

over damp ground or new concrete, place a moisture barrier under the siding. Siding should be 4 to 6

inches above the ground with air circulating freely around and throughout the stack. Acclimatization time

varies with the moisture content of the siding.

Cedar Siding Installation


Acclimatize Siding Before installing

One of the most stable softwoods, Western Red Cedar is nevertheless a natural material and it responds to the environment. Cedar siding can swell or shrink as it gains or loses moisture to reach equilibrium with the moisture content of the surrounding air. Ensuring that the moisture content of cedar siding is at equilibrium before it is installed will minimize movement later on.