CSA S406 provides requirements for constructing preserved wood foundations (PWF) in buildings up to 2-storeys and not more than 600 m2.
Specific issues addressed in this Standard include design and construction requirements, materials, cutting and machining, site preparation, footings, exterior walls, floors, moisture barriers, and site grading.
Numerous figures are provided, as well as non-mandatory information on subjects such as commentary on safe use of pressure-treated wood, requirements for design and supervision, and imperial backfill height tables for wood foundation studs.
1. Scope 1.1 This Standard applies to the selection of materials for, and the fabrication and installation of, preserved wood foundations.
1.2 Specific details are provided for buildings up to two storeys in building height above the foundation and having a building area not exceeding 600 m².
1.3 This Standard provides for the optional use of wood sleeper, poured concrete slab, and suspended wood basement floor systems as components of the preserved wood foundation, and for the use of preserved wood foundations enclosing crawl spaces (see Figures A1 and A6).
1.4 The values given in SI (metric) units are the standard. The values given in parentheses are for information only. Note: In commercial practice, nails are commonly identified by their length in inches. Lumber sizes are expressed in terms of thickness x width, with metric values (mm x mm) referring to standard dry dressed sizes and with imperial values (in x in) referring to nominal nondressed sizes, both in conformance to CSA Standard CAN/CSA-O141, Softwood Lumber.