The Ontario Building Code | Mortar Droppings
9.20.13.10. mortar Droppings
(1) Cavity walls shall be constructed so that mortar droppings are prevented from forming a bridge to allow the passage of rain water across the cavity.
In Plain Language
Mortar droppings within a wall cavity must be controlled as set out in this article, since accumulated mortar can block weep holes and trap moisture against the wall.
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.