These Notes are included for explanatory purposes only and do not form part of the requirements. The number that introduces each Note corresponds to the applicable requirement in this Part.

A-9.15.1.1. Application of Footing and Foundation Requirements to Decks and Similar Constructions.

Because decks, balconies, verandas and similar platforms support occupancies, they are, by definition, considered as buildings or parts of buildings. Consequently, the requirements in Section 9.15. regarding footings and foundations apply to these constructions.

A-9.15.1.1.(1)(c) and 9.20.1.1.(1)(b) Flat Insulating Concrete Form Walls.

Insulating concrete form (ICF) walls are concrete walls that are cast into polystyrene forms, which remain in place after the concrete has cured. Flat ICF walls are solid ICF walls where the concrete is of uniform thickness over the height and width of the wall.

A-9.15.2.4.(1) Preserved Wood Foundations - Design Assumptions.

Tabular data and figures in CSA S406, "Permanent Wood Foundations for Housing and Small Buildings," are based upon the general principles provided in CSA O86, "Engineering Design in Wood," with the following assumptions:

• soil bearing capacity: 75 kPa or more,
• clear spans for floors: 5 000 mm or less,
• floor loadings: 1.9 kPa for first floor and suspended floor, and 1.4 kPa for second storey floor,
• foundation wall heights: 2 400 mm for slab floor, 3 000 mm for suspended wood floor,
• top of granular layer to top of suspended wood floor: 600 mm,
• lateral load from soil pressure: equivalent to fluid pressure of 4.7 kPa per metre of depth,
• ground snowload: 3kPa,
• basic snow load coefficient: 0.6,
• roof loads are carried to the exterior wall,
• dead loads:
  roof 0.50 kPa
  floor 0.47 kPa
  wall (with siding) 0.32 kPa
  wall (with masonry veneer) 1.94 kPa
  foundation wall 0.27 kPa
  partitions 0.20 kPa

A-9.15.3.4.(2) Footing Sizes.

The footing sizes in Table 9.15.3.4. are based on typical construction consisting of a roof, not more than 3 storeys, and centre bearing walls or beams. For this reason, Clause 9.15.3.3.(1)(b) stipulates a maximum supported joist span of 4.9 m.

It has become common to use flat wood trusses or wood I-joists to span greater distances in floors of small buildings. Where these spans exceed 4.9 m, minimum footing sizes may be based on the following method:
(a) Determine for each storey the span of joists that will be supported on a given footing. Sum these lengths (sum₁).
(b) Determine the product of the number of storeys times 4.9 m (sum₂).
(c) Determine the ratio of sum₁ to sum₂.
(d) Multiply this ratio by the minimum footing sizes in Table 9.15.3.4. to get the required minimum footing size.

Example: A 2-storey house is built using wood I-joists spanning 6 m.
(a) sum₁ = 6 + 6 = 12m
(b) sum₂ = 4.9 x 2 = 9.8m
(c) ratio sum₁/sum₂ = 12/9.8 = 1.22
(d) required minimum footing size = 1.22 x 350 mm (minimum footing size provided in Table 9.15.3.4.) = 427 mm.