The Ontario Building Code | Ridge Support

9.23.13.8. Ridge support

(1) Except as provided in Sentence (4), roof rafters and joists shall be supported at the ridge of the roof by,

(a) a loadbearingwall extending from the ridge to suitable bearing, or

(b) a ridge beam supported by not less than 89 mm length of bearing.

(2) Except as provided in Sentence (3), the ridge beam referred to in Sentence (1) shall conform to the sizes and spans shown in Table A-12, provided,

(a) the supported rafter or joist length does not exceed 4.9 m, and

(b) the roof does not support any concentrated loads.

(3) The ridge beam referred to in Sentence (1) need not comply with Sentence (2) where,

(a) the beam is of not less than 38 mm by 140 mm material, and

(b) the beam is supported at intervals not exceeding 1.2 m by not less than 38 mm by 89 mm members extending vertically from the ridge to suitable bearing.

(4) When the roof slope is 1 in 3 or more, ridge support need not be provided when the lower ends of the rafters are adequately tied to prevent outward movement.

(5) Ties required in Sentence (4) are permitted to consist of tie rods or ceiling joists forming a continuous tie for opposing rafters and nailed in accordance with Table 9.23.13.8.

(6) ceiling joists referred to in Sentence (5) shall be fastened together with at least one more nail per joist splice than required for the rafter to joist connection shown in Table 9.23.13.8.

(7) Members referred to in Sentence (6) are permitted to be fastened together either directly or through a gusset plate.

Table 9.23.13.8.
Rafter-to-Joist Nailing (Unsupported Ridge)

Forming Part of Sentences 9.23.13.8.(5) and (6)

Item	Col. 1	Col. 2	Col. 3	Col. 4		Col. 5	Col. 6		Col. 7		Col. 8		Col. 9		Col. 10		Col. 11	Col. 12	Col. 13		Col. 14
	Roof Slope	Rafter Spacing, mm	Minimum Number of Nails not less than 75 mm Long
			Rafter Tied to every Joist										Rafter Tied to Joist every 1.2 m
			building Width up to 8.0 m				Building Width up to 9.8 m						Building Width up to 8.0 m					Building Width up to 9.8 m
			Roof Snow Load, kPa				Roof Snow Load, kPa						Roof Snow Load, kPa					Roof Snow Load, kPa
			1.0   or less	1.5	2.0 or more		1.0 or less		1.5		2.0 or more		1.0 or less	1.5		2.0 or more		1.0 or less	1.5	2.0 or more
1.	1 in 3	406	4	5	6		5		7		8		11	—		—		—	—	—
		610	6	8	9		8		—		—		11	—		—		—	—	—
2.	1 in 2.4	406	4	4	5		5		6		7		7	10		—		9	—	—
		610	5	7	8		7		9		11		7	10		—		—	—	—
3.	1 in 2	406	4	4	4		4		4		5		6	8		9		8	—	—
		610	4	5	6		5		7		8		6	8		9		8	—	—
4.	1 in 1.71	406	4	4	4		4		4		4		5	7		8		7	9	11
		610	4	4	5		5		6		7		5	7		8		7	9	11
5.	1 in 1.33	406	4	4	4		4		4		4		4	5		6		5	6	7
		610	4	4	4		4		4		5		4	5		6		5	6	7
6.	1 in 1	406	4	4	4		4		4		4		4	4		4		4	4	5
		610	4	4	4		4		4		4		4	4		4		4	4	5