The Ontario Building Code | First Coat
9.28.6.3. First Coat
(1) The first coat shall be not less than 6 mm thick, measured from the face of the lath or masonry, fully embedding the lath.
(2) The surface of the first coat shall be scored to provide a key with the second coat.
In Plain Language
The first stucco coat (scratch coat) 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.