Foundations, framing and structure (Part 9)

(1)Foundation drains shall drain to a sewer, drainage ditch or dry well.

(1)Except as provided in Articles 9.15.1.2. and 9.15.1.3., this Section applies to

(a)concrete or unit masonry foundation walls and concrete footings not subject to surcharge

(i)on stable soils with an allowable bearing pressure of 75 kPa or greater, and

(ii)for buildings of wood-frame or masonry construction,

(b)wood-frame foundation walls and wood or concrete footings not subject to surcharge

(i)on stable soils with an allowable bearing pressure of 75 kPa or greater, and

(ii)for buildings of wood-frame construction, and

(c)flat insulating concrete form foundation walls and concrete footings not subject to surcharge (See Note A-9.15.1.1.(1) (c) and 9.20.1.1.(1)(b))

(i)on stable soils with an allowable bearing pressure of 75 kPa or greater, and

(ii)for buildings of light-frame or flat insulating concrete form construction that are not more than 2 storeys in building height, with a maximum floor-to-floor height of 3 m.

(2)Foundations for applications other than as described in Sentence (1) shall be designed in accordance with Section 9.4.

(3)Where a foundation is erected on filled ground, peat or sensitive clay, the footing sizes shall be designed in conformance with Section 4.2.

(4)For the purpose of Sentence (3), sensitive clay means the grain size of the majority of the particles is smaller than 0.002 mm, including leda clay.

(1)Except as provided in Sentence 9.15.3.4.(2), the minimum footing width or area requirements provided in Articles 9.15.3.4. to 9.15.3.7. shall apply to footings, where

(a)the footings support

(i)foundation walls of masonry, concrete, or flat insulating concrete form walls,

(ii)above ground walls of masonry, flat insulating concrete form walls or light wood-frame construction, and

(iii)floors and roofs of light wood-frame construction,

(b)the span of supported joists does not exceed 4.9 m, and

(c)the specified live load on any floor supported by the footing does not exceed 2.4 kPa. (See Table 4.1.5.3.)

(2)Except as provided in Sentence 9.15.3.4.(2), where the span of the supported joists exceeds 4.9 m, footings shall be designed in accordance with Section 4.2.

(3)Where the specified live load exceeds 2.4 kPa footings shall be designed in accordance with Section 4.2.

(1)Except as provided in Sentences (2) and (3) and in Articles 9.15.3.5. to 9.15.3.7., the minimum footing width or area shall comply with Table 9.15.3.4.

(2)Where the supported joist span exceeds 4.9 m in buildings with light wood-frame walls, floors and roofs, strip footing widths shall be determined according to

(a)Section 4.2., or

(b)the following formula:

W = w × [∑sjs/(storeys × 4.9)]

where

W = minimum footing width,

w = minimum width of footings supporting joists not exceeding 4.9 m, as defined by Table 9.15.3.4.,

∑ sjs = sum of the supported joist spans on each storey bearing on an exterior wall whose load is transferred to the footing, or sum of half of the supported joist spans on each storey bearing on both sides of an interior wall whose load is transferred to the footing, and

storeys = number of storeys supported by the footing. (See Note A-9.15.3.4.(2))

(3)Where a foundation rests on gravel, sand or silt in which the water table level is less than the width of the footings below the bearing surface,

(a)the footing width for walls shall be not less than twice the width required by Sentences (1) and (2), and Articles 9.15.3.5. and 9.15.3.6., and

(b)the footing area for columns shall be not less than twice the area required by Sentences (1) and (2) and Article 9.15.3.7.

(1)The strip footing widths for exterior walls shown in Table 9.15.3.4. shall be increased by

(a)65 mm for each storey of masonry veneer over wood-frame construction supported by the foundation wall,

(b)130 mm for each storey of masonry construction supported by the foundation wall, and

(c)150 mm for each storey of flat insulating concrete form wall construction supported by the foundation wall.

(1)Footing thickness shall be not less than the greater of

(a)100 mm, or

(b)the width of the projection of the footing beyond the supported element.

(1)Where step footings are used,

(a)the vertical rise between horizontal portions shall not exceed 600 mm, and

(b)the horizontal distance between risers shall be not less than 600 mm.

(1)Exterior foundation walls shall extend not less than 150 mm above finished ground level.

(1)Except as required in Sentence (2), the thickness of foundation walls made of unreinforced concrete block, concrete core in flat wall insulating concrete forms or solid concrete and subject to lateral earth pressure shall conform to Table 9.15.4.2.-A for walls not exceeding 3.0 m in unsupported height.

(2)The concrete core in flat insulating concrete form foundation walls shall be not less than the greater of

(a)150 mm, or

(b)the thickness of the concrete in the wall above.

(2.1)Foundation walls made of flat insulating concrete form units shall be laterally supported at the top and at the bottom.

(3)The thickness and reinforcing of foundation walls made of reinforced concrete block and subject to lateral earth pressure shall conform to Table 9.15.4.2.-B and Sentences (4) to (7), where

(a)the walls are laterally supported at the top,

(b)average stable soils are encountered, and

(c)wind loads on the exposed portion of the foundation are no greater than 0.70 kPa.

(4)For concrete block walls required to be reinforced, continuous vertical reinforcement shall

(a)be provided at wall corners, wall ends, wall intersections, at changes in wall height, at the jambs of all openings and at movement joints.

(b)extend from the top of the footing to the top of the foundation wall, and

(c)where foundation walls are laterally supported at the top, have not less than 50 mm embedment into the footing, if the floor slab does not provide lateral support at the wall base.

(5)For concrete block walls required to be reinforced, a continuous horizontal bond beam containing not less than one 15 M bar shall be installed

(a)along the top of the wall,

(b)at the sill and head of all openings greater than 1.20 m in width, and

(c)at structurally connected floors.

(6)In concrete block walls required to be reinforced, all vertical bar reinforcement shall be installed along the centre line of the wall.

(7)In concrete block walls required to be reinforced, ladder- or truss-type lateral reinforcement not less than 3.8 mm in diameter (No. 9 ASWG) shall be installed in the bed joint of every second masonry course.

(1)Sentences (2) to (4) pertain to lateral support for walls described in Sentence 9.15.4.2.(1).

(2)Foundation walls shall be considered to be laterally supported at the top if

(a)such walls support a solid masonry superstructure or flat insulating concrete form wall,

(b)the floor joists are embedded in the top of the foundation walls,

(c)the floor system is anchored to the top of the foundation walls with anchor bolts, in which case the joists may run either parallel or perpendicular to the foundation walls, or

(d)they extend from the footing to no more than 300 mm above the finished ground level and are backfilled on both sides such that the difference in elevation between the finished ground levels on either side of the wall is no more than 150 mm.

(3)Unless the wall around an opening is reinforced to withstand earth pressure, the portion of the foundation wall beneath an opening shall be considered laterally unsupported if

(a)the opening is more than 1.2 m wide, or

(b)the total width of the openings in the foundation wall constitutes more than 25% of the length of the wall.

(4)For the purposes of Sentence (3), the combined width of the openings shall be considered as a single opening if the average width is greater than the width of solid wall between them.

(5)Flat insulating concrete form foundation walls shall be considered to be laterally supported at the top if the floor joists are installed according to Article 9.20.17.5.

(1)Except as provided in Sentence (2), not less than 100 mm of coarse clean granular material containing not more than 10% of material that will pass a 4 mm sieve shall be placed beneath floors-on-ground. (See also Subsection 9.13.4. and Note A-9.13.4.)

(2)Granular material need not be installed under

(a)slabs in garages, carports or accessory buildings, or

(b)buildings of industrial occupancy where the nature of the process contained therein permits or requires the use of large openings in the building envelope even during the winter.

(1)Concrete slabs shall be not less than 75 mm thick exclusive of concrete topping. (See Note A-9.16.4.3.(1))

(1)Columns shall be centrally located on a footing conforming to Section 9.15.

(1)Except as permitted in Sentence (2), steel pipe columns shall have an outside diameter of not less than 73 mm and a wall thickness of not less than 4.76 mm.

(2)Columns of sizes other than as specified in Sentence (1) are permitted to be used where the loadbearing capacities are shown to be adequate.

(1)The width or diameter of a wood column shall be not less than the width of the supported member.

(2)Except as provided in Article 9.35.4.2., columns shall be not less than 184 mm for round columns and 140 mm by 140 mm for rectangular columns, unless calculations are provided to show that lesser sizes are adequate.

(1)Crawl spaces shall be considered to be heated where the space

(a)is used as a warm air plenum,

(b)contains heating ducts or heating pipes that are not sealed and insulated to minimize heat loss to the space, or

(c)is not separated from heated space in accordance with Section 9.25.

(2)Heating of heated crawl spaces shall conform to Section 9.33.

(3)Insulation, an air barrier system and a vapour barrier shall be installed in the walls of heated crawl spaces in accordance with Section 9.25.

(1)An access opening of not less than 500 mm by 700 mm shall be provided to each crawl space where the crawl space serves a single dwelling unit, and not less than 550 mm by 900 mm for other crawl spaces.

(2)Access openings shall be fitted with a door or hatch, except when the crawl space is heated and the access opening into the crawl space is from an adjacent heated space.

(1)Unheated crawl spaces shall be ventilated by natural or mechanical means.

(2)Where an unheated crawl space is ventilated by natural means, ventilation shall be provided to the outside air by not less than 0.1 m² of unobstructed vent area for every 50 m² of floor area.

(3)Vents shall be

(a)uniformly distributed on opposite sides of the building, and

(b)designed to prevent the entry of snow, rain and insects.

(1)Where a crawl space is unheated, a ground cover shall be provided consisting of not less than

(a)50 mm of asphalt,

(b)100 mm of 15 MPa Portland cement concrete,

(c)Type S roll roofing, or

(d)0.10 mm polyethylene.

(2)Joints in sheet-type ground cover required in Sentence (1) shall be lapped not less than 100 mm and weighted down.

(1)Except as provided in Sentence (2), the unobstructed vent area shall be not less than 1/300 of the insulated ceiling area.

(2)Where the roof slope is less than 1 in 6 or in roofs that are constructed with roof joists, the unobstructed vent area shall be not less than 1/150 of the insulated ceiling area.

(3)Required vents may be roof type, eave type, gable-end type or any combination thereof, and shall be distributed

(a)uniformly on opposite sides of the building,

(b)with not less than 25% of the required openings located at the top of the space, and

(c)with not less than 25% of the required openings located at the bottom of the space.

(4)Except where each roof joist space referred to in Sentence (2) is separately vented, roof joist spaces shall be interconnected by installing purlins not less than 38 mm by 38 mm on the top of the roof joists.

(5)Vents shall comply with CAN3-A93-M, "Natural Airflow Ventilators for Buildings."

(1)Except as provided in Sentence (2), where venting is provided to a roof joist space, not less than 63 mm of space shall be provided between the top of the insulation and the underside of the roof sheathing.

(2)Where venting is provided at the junction of sloped roofs and exterior walls and where preformed baffles are used to contain the insulation, the baffles shall

(a)provide an unobstructed air space, between the insulation and the underside of the roof sheathing, that is

(i)not less than 25 mm in dimension, and

(ii)of sufficient cross area to meet the attic or roof space venting requirements of Article 9.19.1.2., and

(b)extend vertically not less than 50 mm above the top of the insulation.

(3)Ceiling insulation shall be installed in a manner that will not restrict the free flow of air through roof vents or through any portion of the attic or roof space.

(1)Every attic or roof space shall be provided with an access hatch where the attic or roof space

(a)measures not less than

(i)10 m² in area,

(ii)1,000 mm in length or width, and

(iii)600 mm in height over at least the area described in Subclauses (i) and (ii), or

(b)contains a fuel-fired appliance. (See Note A-9.19.2.1.(1))

(2)The hatch required in Sentence (1) shall be not less than 550 mm by 900 mm except that, where the hatch serves not more than one dwelling unit, the hatch may be reduced to 0.32 m² in area with no dimension less than 500 mm. (See Note A-9.19.2.1.(2))

(3)Hatchways to attic or roof spaces shall be fitted with doors or covers.

(1)Except for masonry veneer where each masonry unit is supported individually by the structural backing, masonry veneer shall consist of solid masonry units not less than 70 mm thick.

(2)Veneer described in Sentence (1) over wood-frame walls shall have not less than a 25 mm air space behind the veneer.

(3)Masonry veneer less than 90 mm thick shall have unraked joints.

(4)Masonry veneer shall conform to Subsection 4.3.2. where the masonry units are required to be individually supported by the structural backing.

(1)Masonry veneer 70 mm or more in thickness and resting on a bearing support shall be tied to masonry backing or to wood framing members with straps that are

(a)corrosion-resistant,

(b)not less than 0.76 mm thick,

(c)not less than 22 mm wide,

(d)shaped to provide a key with the mortar,

(e)pre-bent during manufacture to a right angle within 6 mm of the fastener hole,

(f)fastened with

(i)corrosion-resistant wood screws conforming to Sentence 9.23.3.1.(3) that have a minimum diameter of 4.16 mm (No. 8) and a wood penetration of not less than 38 mm, or

(ii)corrosion-resistant common spiral nails conforming to Sentence 9.23.3.1.(1) that are not less than 76 mm long and have a wood penetration of not less than 63 mm, and

(g)spaced in accordance with Table 9.20.9.5.

(2)Where hot-dipped, zinc-coated straps are used to meet the requirements of Sentence (1), they shall be pre-bent and pre-drilled or pre-punched prior to hot-dip, zinc-coated galvanizing.

(3)Masonry veneer individually supported by masonry or wood-frame backing shall be secured to the backing in conformance with Subsection 4.3.2.

(4)The straps described in Sentence (1) may be installed against one of the sheathings listed in Table 9.23.17.2.-A provided that

(a)the tie is in contact with the exterior surface of the sheathing, and

(b)the sheathing beneath the tie is not compressed.

(1)Weep holes spaced not more than 800 mm apart shall be provided at the bottom of

(a)cavities in cavity walls, and

(b)cavities or air spaces in masonry veneer walls.

(2)The cavities or air spaces described in Sentence (1) shall include those above lintels over window and door openings required to be flashed in conformance with Article 9.20.13.3.

(3)The weep holes required in Sentence (1) shall be in a location such that any water that collects in the cavity or space will be directed to the exterior of the building.

(1)This Section applies to,

(a)rectangular masonry or concrete chimneys not more than 12 m in height serving fireplaces or serving appliances having a combined total rated heat output of 120 kW or less, and

(b)flue pipes serving solid fuel-burning appliances.

(2)Reserved.

(3)Except as provided in Sentence 9.21.1.3.(1), chimneys (other than those described in Sentence (1) and Sentence 9.21.1.2.(1)), gas vents and flue pipes serving gas-, oil- or solid fuel-burning appliances and associated equipment shall conform to Section 6.3.

(1)A chimney flue shall extend not less than

(a)900 mm above the highest point at which the chimney comes in contact with the roof, and

(b)600 mm above the highest roof surface or structure within 3 m of the chimney. (See Note A-9.21.4.4.(1))

(1)The clearance between masonry or concrete chimneys and combustible framing material shall be not less than,

(a)50 mm for interior chimneys, and

(b)12 mm for exterior chimneys. (See Note A-9.21.5.1.(1))

(2)A clearance of not less than 150 mm shall be provided between a cleanout opening and combustible material.

(3)Combustible flooring, subflooring and ceiling finishes shall have not less than a 12 mm clearance from masonry or concrete chimneys.

(1)The distance from the back of the fire chamber to the plane of the fireplace opening shall be not less than 300 mm.

(1)Except as required in Sentence (2), fireplaces shall have a noncombustible hearth extending not less than 400 mm in front of the fireplace opening measured from the facing, and not less than 200 mm beyond each side of the fireplace opening.

(2)Where the fire chamber floor is elevated more than 150 mm above the hearth, the dimension of the hearth measured perpendicular to the plane of the fireplace opening shall be increased by not less than

(a)50 mm for an elevation above 150 mm and not more than 300 mm, and

(b)an additional 25 mm for every 50 mm in elevation above 300 mm.

(1)This Section applies to constructions where wall, floor and roof planes are generally comprised of lumber frames of small repetitive structural members, or engineered components, and where

(a)roof and wall planes are clad, sheathed or braced on at least one side,

(b)the small repetitive structural members are spaced not more than 600 mm o.c.,

(c)the constructions do not serve as foundations,

(d)the specified live load on supported subfloors and floor framing does not exceed 2.4 kPa, and

(e)the span of any structural member does not exceed 12.20 m. (See Note A-9.23.1.1.(1))

(2)Where the conditions in Sentence (1) are exceeded for wood construction, the design of the framing and fastening shall conform to Subsection 4.3.1.

(1)Except as required in Sentence (2) and Article 9.23.14.10., spans for wood joists and rafters shall conform to the spans shown in Span Tables 9.23.4.2.-A to 9.23.4.2-G for the uniform live loads shown in the Tables. (See Article 9.4.2.2.)

(2)Spans for floor joists that are not selected from Span Tables 9.23.4.2.-A and 9.23.4.2-B and that are required to be designed for the same loading conditions, shall not exceed the design requirements for uniform loading and vibration criteria. (See Note A-9.23.4.2.(2))

(3)Spans for built-up wood and glued-laminated timber floor beams shall conform to the spans in Span Tables 9.23.4.2.-H to 9.23.4.2-K. (See Article 9.4.2.2.)

(4)Spans for roof ridge beams shall conform to the spans in Span Table 9.23.4.2.-L for the uniform snow load shown. (See Articles 9.4.2.2. and 9.23.14.8.)

(1)Floor, roof and ceiling framing members are permitted to be notched provided the notch is located on the top of the member within half the joist depth from the edge of bearing and is not deeper than one-third the joist depth, unless the depth of the member is increased by the size of the notch.

(1)Wall studs shall not be notched, drilled or otherwise damaged so that the undamaged portion of the stud is less than two-thirds the depth of the stud if the stud is loadbearing or 40 mm if the stud is non-loadbearing, unless the weakened studs are suitably reinforced.

(1)Except as provided in Sentence (2), the size and spacing of studs shall conform to Table 9.23.10.1.

(2)Studs for walls not listed in Table 9.23.10.1. and supporting roof loads shall conform to Span Tables 9.23.10.1.-A to 9.23.10.1.-D, provided

(a)the studs are clad with not less than 9.5 mm thick plywood, OSB or waferboard sheathing on the exterior face, and not less than 12.5 mm gypsum board on the interior face,

(b)solid bridging is provided at not more than 1.2 m o.c,

(c)the studs are fastened to the top and bottom plates with no fewer than three 82 mm toe nails,

(d)the double top plates are fastened together with not less than 76 mm nails spaced not more than 200 mm o.c,

(e)roof framing members spaced not more than 600 mm are fastened to the top plates with no fewer than four 82 mm toe nails, and

(f)the bottom plate is fastened to the floor joists, blocking or rim joist with not less than 82 mm nails spaced not more than 200 mm o.c.

(See Note A-9.23.10.1.(2))

(1)Floor joists supporting roof loads shall not be cantilevered more than 400 mm beyond their supports where 38 mm by 184 mm joists are used and not more than 600 mm beyond their supports where 38 mm by 235 mm or larger joists are used.

(2)The cantilevered portions referred to in Sentence (1) shall not support floor loads from other storeys unless calculations are provided to show that the design resistances of the cantilevered joists are not exceeded.

(3)Where cantilevered floor joists described in Sentences (1) and (2) are at right angles to the main floor joists, the tail joists in the cantilevered portion shall extend inward away from the cantilever support a distance equal to not less than 6 times the length of the cantilever, and shall be end nailed to an interior doubled header joist in conformance with Table 9.23.3.4.

(1)This Section applies to sheet steel study for use in non-loadbearing exterior and interior walls.

(2)Where loadbearing steel studs are used, they shall be designed in conformance with Part 4.

(1)Except as required in Article 9.24.2.4., steel studs in non-loadbearing interior walls shall have a metal thickness of not less than 0.46 mm.

(1)Runners for interior and exterior non-loadbearing walls shall have a thickness not less than the thickness of the corresponding studs and shall have not less than 30 mm flanges.

(1)Steel studs used in walls required to have a fire-resistance rating shall be installed so that there is not less than a 12 mm clearance between the top of the stud and the top of the runner to allow for expansion in the event of fire.

(2)Except as provided in Article 9.24.3.6., studs in walls referred to in Sentence (1) shall not be attached to the runners in a manner that will prevent such expansion.

(3)Framing above doors with steel door frames in non-loadbearing fire separations required to have a fire-resistance rating shall consist of 2 runners on the flat fastened back to back. (See Note A-9.24.3.2.(3))

(4)The lower runner required in Sentence (3) shall be cut through the flanges and be bent at each end to extend upwards at least 150 mm and fastened to the adjacent studs.