The Ontario Building Code | Lath and Reinforcing
9.28.1.2. Lath and Reinforcing
(1) stucco lath or reinforcing shall be used to attach stucco to any substrate other than masonry.
(2) stucco lath or reinforcing shall be used to attach stucco to masonry where,
(a) the masonry is soft-burned tile or brick of less strength than the stucco, or
(b) the masonry surface is not sound, clean and sufficiently rough to provide a good key.
(3) stucco applied over masonry chimneys shall be reinforced.
In Plain Language
Lath and reinforcing, the mesh or wire embedded in stucco for added strength, must meet the requirements set out in this article.
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.