The Ontario Building Code | Dimensions for Risers

9.8.4.1. Dimensions for Risers

(1) The rise, which is measured as the vertical nosing-to-nosing distance, shall conform to Table 9.8.4.1.

Table 9.8.4.1.
Rise, Run and Tread Depth for Rectangular Treads

Forming Part of Sentences 9.8.4.1.(1) and 9.8.4.2.(1)

Item	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7
	Stair Type	All Steps		Rectangular Treads
		Rise, mm		Run, mm		Tread Depth, mm
		max.	min.	max.	min.	max.	min.
1.	service and mezzanines in live/work units(1)	no limit	125	355	no limit	355	no limit
2.	Private(2)	200	125	355	210	355	235
3.	Public(3)	180	125	no limit	280	no limit	280

Notes to Table 9.8.4.1.:

⁽¹⁾ service stairs are stairs that serve areas used only as service rooms or service spaces and stairs that serve mezzanines not exceeding 20 m² within live/work units.

⁽²⁾ Private stairs are interior stairs within dwelling units and exterior stairs serving a single dwelling unit or a garage that serves a single dwelling unit.

Note: On July 1, 2017, Note 2 to Table 9.8.4.1. of Division B of the Regulation is revoked and the following substituted: (See: O. Reg. 139/17, s. 77)

⁽²⁾ Private stairs are:

(a) interior stairs within a house or an individual dwellingunit,

(b) exterior stairs serving a house or an individual dwelling unit, and

(c) exterior stairs serving a garage that serves a house or an individual dwelling unit.

⁽³⁾ Public stairs are all stairs not described as service stairs or private stairs.