9.3.2.

(1) Lumber for joists, rafters, trusses and beams and for the uses listed in Table 9.3.2.1. shall be identified by a grade stamp to indicate its grade as determined by the NLGA, “Standard Grading Rules for Canadian Lumber (Interpretation Included)”.

(1) Except for joists, rafters, trusses and beams, visually graded lumber shall conform to the grades in Table 9.3.2.1.v1

(1) Machine stress rated lumber shall conform to the requirements of Subsection 4.3.1.

(1) OSB, waferboard and plywood used for roof sheathing, wall sheathing and subflooring shall be legibly identified on the face of the material indicating,

(a) the manufacturer of the material,

(b) the standard to which it is produced, and

(c) that the material is of an exterior type.

(1) Moisture content of lumber shall be not more than 19% at the time of installation.

(1) Lumber dimensions referred to in this Part are actual dimensions determined in conformance with CSA O141, “Softwood Lumber”.

(1) The thickness specified in this Part for plywood, hardboard, particleboard, OSB and waferboard shall be subject to the tolerances permitted in the standards referenced for these products unless specifically indicated in this Part.

(1) Joist, rafter, lintel and beam members up to 5% less than the actual Canadian standard sizes are permitted to be used provided the allowable spans for the grade and species of lumber under consideration are reduced 5% from those shown in the span tables for full size members.

(1) In localities where termites are known to occur,

(a) clearance between structural wood elements and the finished ground level directly below them shall be not less than 450 mm and, except as provided in Sentence (2), all sides of the supporting elements shall be visible to permit inspection, or

(b) structural wood elements, supported by elements in contact with the ground or exposed over bare soil, shall be pressure-treated with a chemical that is toxic to termites.

(2) In localities where termites are known to occur and foundations are insulated or otherwise finished in a manner that could conceal a termite infestation,

(a) a metal or plastic barrier shall be installed through the insulation and any other separation or finish materials above finished ground level to control the passage of termites behind or through the insulation, separation or finish materials, and

(b) all sides of the finish supporting assembly shall be visible to permit inspection.

(3) Structural wood elements shall be pressure-treated with a preservative to resist decay,

(a) where the vertical clearance between structural wood elements and the finished ground level is less than 150 mm, or

(b) where,

(i) the wood elements are not protected from exposure to precipitation, and

(ii) the configuration is conducive to moisture accumulation.

(4) Structural wood elements used in retaining walls and cribbing shall be pressure-treated with a preservative to resist decay, where,

(a) the retaining wall or cribbing supports ground that is critical to the stability of building foundations, or

(b) the retaining wall or cribbing is greater than 1.2 m in height.

(5) Where wood is required by this Article to be treated to resist termites or decay, such treatment shall be in accordance with the requirements of,

(a) CSA O80.1, “Preservative Treatment of All Timber Products by Pressure Processes”,

(b) CSA O80.2, “Preservative Treatment of Lumber, Timber, Bridge Ties and Mine Ties by Pressure Processes”,

(c) CSA O80.9, “Preservative Treatment of Plywood by Pressure Processes”,

(d) CSA O80.15, “Preservative Treatment of Wood for Building Foundation Systems, Basements and Crawl Spaces by Pressure Processes”, or

(e) CSA O80.34, “Pressure Preservative Treatment of Lumber and Timbers with Borates for Use Out of Ground Contact and Continuously Protected from Liquid Water”.

(6) In addition to the requirements of Clause (5)(e), where wood is protected in accordance with CSA O80.34, “Pressure Preservative Treatment of Lumber and Timbers with Borates for Use Out of Ground Contact and Continuously Protected from Liquid Water”, the wood shall be,

(a) protected from direct exposure to moisture during and after the completion of construction, and

(b) separated from permeable supporting materials by a moisture barrier that is resistant to all expected mechanisms of deterioration in the service environment when the vertical clearance to the ground is less than 150 mm.

(7) Wood that is required by this Article to be treated to resist termites or decay shall be identified by a mark to indicate its conformance to the relevant required standard.