The Ontario Building Code | Attic or Roof Space Access
3.6.4.4. attic or Roof Space Access
(1) An attic or roof space more than 600 mm high shall be provided with access from the floor immediately below by a hatchway not less than 550 mm by 900 mm or by a stairway.
In Plain Language
An attic or roof space taller than 600 mm needs access from the floor below through a hatchway at least 550 mm by 900 mm, or a stairway, so maintenance and inspection personnel (and firefighters) can get in.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.