Ontario Building Code Exam: Building Structural

Under Part 9 of the 2024 Ontario Building Code, what is the minimum depth of frost protection required for foundations of heated buildings on stable, undisturbed soil in Southern Ontario, where prescriptive rules apply?

• A1.2 m (4 feet)
• B0.6 m (2 feet)
• C1.8 m (6 feet)
• D1.0 m (3.3 feet)

Under Division B, Table 9.23.10.1 of the 2024 Ontario Building Code, what is the maximum spacing of studs in loadbearing exterior walls supporting a roof and one floor?

• A400 mm o.c.
• B600 mm o.c.
• C300 mm o.c.
• D450 mm o.c.

Under the 2024 Ontario Building Code, what is the minimum compressive strength of concrete required for unreinforced footings and foundation walls not exposed to the weather?

• A15 MPa
• B20 MPa
• C25 MPa
• D32 MPa

Which of the following loads is classified as a 'Dead Load' under Division B, Part 4 of the 2024 Ontario Building Code?

• AThe self-weight of structural elements and permanent architectural finishes
• BThe load imposed by occupants and movable equipment
• CThe temporary load caused by snow accumulation on the roof
• DThe lateral force exerted by wind pressure on the building facade

Under Division B, Table 9.23.14.3.A of the 2024 Ontario Building Code, what is the minimum thickness of plywood subfloor sheathing required for floor joists spaced at 400 mm (16 inches) o.c.?

• A15.5 mm
• B12.5 mm
• C18.5 mm
• D9.5 mm

Under Division B, Table 9.15.3.4 of the 2024 Ontario Building Code, what reference column spacing is used to determine the minimum footing area for columns supporting wood beams in residential buildings?

• A3.0 m o.c.
• B2.4 m o.c.
• C3.6 m o.c.
• D4.0 m o.c.

Under Division B, Table 9.15.4.2.A of the 2024 Ontario Building Code, what is the minimum thickness of a solid concrete foundation wall supporting lateral earth pressure where the height of unfinished basement wall is 2.5 m and the depth of lateral soil is 2.0 m?

• A200 mm
• B150 mm
• C250 mm
• D300 mm

What is the minimum thickness required for a concrete slab-on-ground cast directly on granular fill in a residential basement under Division B, Article 9.16.4.3 of the 2024 Ontario Building Code?

• A75 mm
• B100 mm
• C50 mm
• D90 mm

Under Division B, Article 9.23.6.1 of the 2024 Ontario Building Code, what is the minimum diameter and maximum spacing of anchor bolts used to fasten sill plates to foundation walls?

• A12.7 mm diameter at 2.4 m spacing
• B9.5 mm diameter at 1.8 m spacing
• C16.0 mm diameter at 3.0 m spacing
• D12.7 mm diameter at 1.2 m spacing

Under the 2024 Ontario Building Code, when executing an excavation adjacent to an existing footing, what is the maximum slope (angle of repose) allowed without requiring shoring or underpinning of the existing structure?

• A1 horizontal to 1 vertical (45 degrees) below the footing
• B2 horizontal to 1 vertical (26.5 degrees) below the footing
• C1.5 horizontal to 1 vertical below the footing
• DShoring is always required regardless of the slope

Under Division B, Section 9.14 of the 2024 Ontario Building Code, where should the subsoil drainage pipe (drain tile) be positioned relative to the footing?

• AOn undisturbed soil beside the footing, with the top of the pipe below the top of the foo…
• BDirectly underneath the footing, centered in the concrete pour
• COn top of the footing, covered with concrete
• DAbove the basement slab level along the interior wall face

Under Division B, Section 4.1.6 of the 2024 Ontario Building Code, the specified snow load (S) on a roof is calculated as a combination of which factors?

• AThe ground snow load (Ss) modified by factors plus the associated rain load (Sr)
• BThe wind load velocity pressure multiplied by the roof area
• CThe dead load of the roof structure plus a standard occupancy live load
• DThe seismic spectral acceleration coefficient multiplied by the roof slope

Under Part 9 of the 2024 Ontario Building Code, what is the minimum temperature at which concrete must be maintained during its initial curing period?

• A10°C for at least 3 days
• B0°C for at least 7 days
• C5°C for at least 24 hours
• D15°C for at least 5 days

Under Division B, Table 9.17.3.1.A of the 2024 Ontario Building Code, what is the minimum wall thickness required for a standard structural steel pipe column in a single-family dwelling?

• A4.76 mm
• B3.18 mm
• C6.35 mm
• D2.50 mm

Under Division B, Article 9.23.9.8 of the 2024 Ontario Building Code, what is the requirement for floor joists when a loadbearing wall runs parallel to the floor joists?

• AThe wall must be supported by double joists or structural framing of equivalent capacity
• BNo extra joists are required if the wall is directly over a single joist
• CThe joists must be spaced at 300 mm o.c. throughout the entire room
• DBridging must be spaced every 1.0 m along the parallel joists

Under Division B, Section 9.27 of the 2024 Ontario Building Code, what is the minimum overlap required at joints for sheathing paper applied to exterior walls?

• A100 mm for horizontal joints, 150 mm for vertical joints
• B50 mm for horizontal joints, 100 mm for vertical joints
• C150 mm for horizontal joints, 300 mm for vertical joints
• DNo overlap is required if the joints are taped

Under Division B, Article 9.23.13.7 of the 2024 Ontario Building Code, what is the purpose and primary location for collar ties in a wood-frame roof?

• ATo resist wind uplift and thrust, located in the middle third of the rafter height
• BTo support the ceiling drywall, located at the bottom of the rafter
• CTo support the roof ridge board, located at the ridge joint
• DTo attach the fascia board, located at the rafter tails

Under Division B, Article 9.17.4.1 of the 2024 Ontario Building Code, what is the minimum nominal size for solid wood columns (posts) supporting residential wood beams?

• A140 mm x 140 mm
• B89 mm x 89 mm
• C140 mm x 190 mm
• D38 mm x 140 mm

Under Division B, Section 9.20 of the 2024 Ontario Building Code, which type of mortar is required for loadbearing exterior walls?

• AType S or Type N
• BType O only
• CType K only
• DAny mortar type is acceptable

Under Division B, Table 9.23.10.1 of the 2024 Ontario Building Code, what is the maximum allowable spacing of studs in non-loadbearing interior partitions?

• A600 mm o.c.
• B400 mm o.c.
• C450 mm o.c.
• D300 mm o.c.

Under Division B, Article 9.23.11.4 of the 2024 Ontario Building Code, what is the standard requirement for joints in the doubled top plates of wood-frame loadbearing walls?

• AJoints shall be staggered not less than one stud spacing, and plates shall be lapped or t…
• BJoints may occur at the same location provided a steel strap is nailed across
• CJoints must be lapped by at least 75 mm with no stagger required
• DSingle top plates are always permitted if rafters align over the studs

Under Division B, Table 9.23.3.5.B of the 2024 Ontario Building Code, what is the maximum spacing of nails along the edges of plywood subfloor sheathing?

• A150 mm
• B300 mm
• C200 mm
• D100 mm

Under Division B, Article 9.16.2.1 of the 2024 Ontario Building Code, what is the minimum thickness of polyethylene film required as a damp-proofing barrier beneath a residential concrete slab-on-ground?

• A0.15 mm
• B0.05 mm
• C0.10 mm
• D0.20 mm

Under Division B, Table 9.15.3.4 of the 2024 Ontario Building Code, what is the minimum footing width for a 1-storey wood-frame exterior wall on stable soil with a bearing capacity of 75 kPa?

• A350 mm
• B250 mm
• C450 mm
• D300 mm

Under Part 9 of the 2024 Ontario Building Code, what is the minimum thickness of gypsum board required for ceilings where the framing is spaced at 600 mm o.c. without supports along the edges?

• A12.7 mm
• B9.5 mm
• C15.9 mm
• D19.0 mm

Under Division B, Table 9.4.4.1 of the 2024 Ontario Building Code, what is the prescriptive design bearing pressure for soft clay?

• A75 kPa
• B150 kPa
• C50 kPa
• D100 kPa

Which of the following describes the correct structural location of an air barrier system in an insulated wood-frame wall assembly under the 2024 Ontario Building Code?

• AIt can be located on the interior, exterior, or within the wall assembly, provided it is…
• BIt must always be located on the cold exterior side of the insulation
• CIt must always be located directly behind the interior drywall
• DIt must be located in the exact center of the wall cavity

Under Part 9 of the 2024 Ontario Building Code, what is the maximum height of retained soil allowed for a prescriptive concrete retaining wall before a professional engineer's structural design is required?

• A1.2 m
• B0.6 m
• C2.0 m
• D1.5 m

Under Division B, Article 9.23.9.4 of the 2024 Ontario Building Code, when is strap bridging or wood blocking required for floor joists?

• AWhen the joist span exceeds 2.1 m or when joist depth-to-thickness ratio exceeds 6:1
• BOnly when the joist span exceeds 4.5 m
• CFor all joists regardless of span or depth
• DOnly when joists support a masonry wall above

What is the standard species group and grade of lumber assumed for prescriptive span tables in Part 9 of the 2024 Ontario Building Code unless otherwise noted?

• ASpruce-Pine-Fir (S-P-F) No. 1/No. 2
• BDouglas Fir-Larch Select Structural
• CNorthern Aspen Stud Grade
• DSouthern Yellow Pine No. 3

Under Division B, Table 9.15.3.4 of the 2024 Ontario Building Code, what is the minimum footing width for a 2-storey wood-frame dwelling with a basement, supported on soil with a design bearing capacity of 75 kPa?

• A575 mm
• B350 mm
• C475 mm
• D700 mm

Under Division B, Article 9.4.3.1 of the 2024 Ontario Building Code, what is the maximum allowable elastic deflection for a floor member supporting a plaster ceiling?

• AL / 360
• BL / 240
• CL / 180
• DL / 480

When using engineered wood I-joists in a floor system designed under Part 9 of the 2024 Ontario Building Code, how must the structural capacity and span limits be determined?

• AIn accordance with manufacturer's span tables and evaluations, engineered in accordance w…
• BBy using the standard solid lumber span tables in the OBC Appendix
• CBy applying a 50% safety reduction factor to standard 2x10 lumber tables
• DWood I-joists are not permitted under Part 9 and must be designed under Part 4 only

Under the 2024 Ontario Building Code, what is the load combination factor applied to the specified live load when performing a structural design using Ultimate Limit States (ULS) for a standard office building?

• A1.5
• B1.25
• C1.4
• D1.0

Under Division B, Article 4.1.5.8 of the 2024 Ontario Building Code, when is a structural designer allowed to apply a live load reduction factor (LLRF) to the specified live load of a floor?

• AWhen the tributary area of the structural member exceeds 20 square meters
• BWhen the building is classified as an industrial warehouse
• COnly for roofs with a slope exceeding 30 degrees
• DWhen the building is located in an area with low seismic hazard

Under Division B, Section 4.1.7 of the 2024 Ontario Building Code, how is the reference wind velocity pressure (q) determined for structural design?

• ABased on a 1-in-50-year return period probability found in Supplementary Standard SB-1
• BBased on a standard value of 0.5 kPa for all regions in Ontario
• CBy conducting a site-specific wind tunnel test for every building
• DBy measuring the average wind speed over the previous 10 years

Under Division B, Section 9.20 of the 2024 Ontario Building Code, what is the maximum vertical spacing of metal ties required to bond the wythes of a cavity wall?

• A400 mm o.c.
• B600 mm o.c.
• C500 mm o.c.
• D300 mm o.c.

Under Division B, Section 9.16 of the 2024 Ontario Building Code, what is the requirement for the concrete thickness of a slab-on-ground when heating pipes or ducts are embedded within the slab?

• AThe slab must be at least 75 mm thick, excluding the diameter of the pipes or ducts
• BThe slab must be at least 150 mm thick overall
• CThe slab can remain 75 mm thick, including the pipes
• DEmbedding heating pipes or ducts in structural slabs is prohibited

Under Division B, Part 4 of the 2024 Ontario Building Code, what is the specified minimum live load for bedrooms in a residential occupancy?

• A1.9 kPa
• B1.5 kPa
• C2.4 kPa
• D4.8 kPa

Under Division B, Section 9.15 of the 2024 Ontario Building Code, when are concrete foundation walls required to contain horizontal reinforcement?

• AWhen the height of unbalanced backfill exceeds limits in Table 9.15.4.2.C or when resisti…
• BAll concrete foundation walls must contain horizontal reinforcement
• COnly when the wall thickness is less than 150 mm
• DOnly when the building is three storeys in height

Under Division B, Article 9.20.8.3 of the 2024 Ontario Building Code, what is the minimum length of end bearing required for a beam supported on a masonry wall?

• A90 mm
• B40 mm
• C150 mm
• D100 mm

Under Division B, Section 4.1.6 of the 2024 Ontario Building Code, how is the roof slope factor (Cs) applied to reduce the design snow load on steep roofs?

• AIt decreases linearly from 1.0 at a slope of 15 degrees down to 0 at a slope of 70 degrees
• BIt remains 1.0 for all slopes to ensure safety against sliding snow
• CIt increases as the roof slope increases to account for wind accumulation
• DIt is only applied to flat roofs with slopes less than 10 degrees

Under Division B, Table 4.1.2.1 of the 2024 Ontario Building Code, what are the four structural Importance Categories used to determine design loads for buildings?

• ALow, Normal, High, and Post-disaster
• BResidential, Commercial, Industrial, and Agricultural
• CClass A, Class B, Class C, and Class D
• DPrescriptive, Engineered, Special, and Exempt

Under Division B, Article 9.23.3.3 of the 2024 Ontario Building Code, what is the required nailing pattern for fastening the individual members of a built-up wood beam?

• ANails must be staggered, spaced not more than 450 mm o.c. along the length, with double n…
• BA single row of nails at 600 mm o.c. along the top edge only
• CNails are not permitted; built-up beams must be bolted with 16 mm bolts
• DNails must be placed at 150 mm o.c. along both edges and the centerline

Under Division B, Section 9.23 of the 2024 Ontario Building Code, how does the allowable span of a Spruce-Pine-Fir (S-P-F) No. 2 roof rafter compare to a Douglas Fir-Larch No. 1 rafter under the same design load?

• ADouglas Fir-Larch No. 1 has a longer allowable span because it has higher strength and st…
• BSpruce-Pine-Fir (S-P-F) No. 2 has a longer allowable span because it is lighter
• CThey have identical allowable spans because all wood species are grouped together in Part…
• DDouglas Fir-Larch No. 1 has a shorter allowable span because it is more prone to warping

Under the 2024 Ontario Building Code, what is the minimum air entrainment percentage required for concrete used in exterior stairs, steps, or slabs exposed to freeze-thaw cycles and de-icing salts?

• A3% to 6% for 20 mm aggregate, or up to 8% depending on aggregate size
• BNo air entrainment is required if the concrete strength is over 35 MPa
• CExactly 10% for all concrete exposed to the weather
• DAir entrainment is only required for interior slabs with radiant heating

Under Division B, Article 9.20.5.2 of the 2024 Ontario Building Code, what is the minimum bearing length of a masonry lintel supported on a masonry wall?

• A150 mm
• B100 mm
• C200 mm
• D75 mm