Physical Properties

Physical properties of commercially available Canadian softwood species are summarized in table format below.

Density, hardness and thermal conductivity

Thermal conductivity is given as a coefficient. To calculate its resistance (RSI value), divide length by thermal conductivity. For example one inch of S-P-F would give 0.0254 / 0.13 = 0.195 W / (m2 K) or 1.1 BTU / (ft2 hr F).

Resistance to decay and absorption of treatment

Surface Smoothness

There are three general levels of surface smoothness to which lumber is manufactured. Rough lumber is lumber which has been sawn, trimmed, and edged. The saw blades used for mass manufacturing are coarse toothed for speed of production and, as a result, rough lumber is usually characterized by striations or saw lines.

Surfaced lumber is lumber which has been surfaced after sawing by passing through a planing machine for the purpose of adding smoothness and uniformity of size on one side (S1S), two sides (S2S), four sides (S4S), or a combination of sides and edges.