The Ontario Building Code | Chimney Caps
9.21.4.6. Chimney Caps
(1) The top of a chimney shall have a waterproof cap of reinforced concrete, masonry or metal.
(2) The cap required in Sentence (1) shall slope from the lining and be provided with a drip not less than 25 mm from the chimney wall.
(3) Cast-in-place concrete caps shall be separated from the chimney linerby a bond break and be sealed at that location.
(4) Jointed precast concrete or masonry chimney caps shall have flashing installed beneath the cap extending from the liner to the drip edge.
In Plain Language
Chimney caps are required meeting the requirements set out in this article, protecting the chimney from water infiltration and debris at its top opening.
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.