The Ontario Building Code | Prohibition of Welding of Pipes and Fittings
7.3.3.3. Prohibition of Welding of pipes and Fittings
(1) Cast iron soil pipe and fittings shall not be welded.
(2) Galvanized steel pipe and fittings shall not be welded.
In Plain Language
Welding of plumbing pipes and fittings is generally prohibited, since welding can change the properties of the pipe material in ways that compromise the plumbing system's integrity.
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.