NBC 2015 Div B-9.8.9.5. Treads 1) Stair treads of lumber, plywood or O-2 grade OSB within dwelling units shall be not less than 25 mm actual thickness, except that if open risers are used and the distance between stringers exceeds 750 mm, the treads shall be not less than 38 mm actual thickness.
I have no issue understanding what the rule is asking for but I have a language question.
My question is: If the wood treads are NOT within a dwelling unit, does the same rule apply? Is there a different article that would apply to stairs outside the dwelling unit or to public buildings that fall int the scope of Part 9.
One Response
If you haven’t seen it already, the NBC User Guide provides some good commentary on this (https://nrc-publications.canada.ca/eng/view/ft/?id=72431bc3-7a2e-4725-bdca-aace4b7f3837)
In practice, I have seen 9.8.9.5 generally applied to stairs “serving” dwelling units, as opposed to “within”. The user guide also seems to use these terms interchangeably.
I would think that public stairs should be designed per 9.8.9.1(b).