PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code
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9.20.3.2.Mortar and Grout Mixes
(1) Mortar types shall be in accordance with Table 9.20.3.2.-A.
(2) Mortar for glass block masonry shall be
(a) Type S Portland cement-lime where exposed to the exterior, or
(b) Type S or N where protected from the exterior.
(3) Mortar shall be mixed within the proportion limits provided in Table 9.20.3.2.-B, with sufficient water to bring the
mixture to a consistency adequate for laying masonry units.
(4) Grout shall be mixed within the proportion limits provided in Table 9.20.3.2.-C, with sufficient water to provide a
suitable flow to fill all voids completely, without excessive segregation or bleeding.
(5) Except as provided in Sentence (6), mortar shall be used and placed in final position
(a) within 1.5 h after mixing when the air temperature is 25°C or higher, or
(b) within 2.5 h after mixing when the air temperature is less than 25°C.
(6) Mortar and grout containing a set-control admixture shall be manufactured off-site in a batching plant and shall be
used and placed in final position within a time not exceeding the useful life stipulated by the manufacturer.
(7) Grout used for reinforced masonry shall be placed in accordance with the requirements of CAN/CSA-A371,
“Masonry construction for buildings.”
Table 9.20.3.2.-A
Mortar Use
Forming Part of Sentence 9.20.3.2.(1)
Location Building Element Mortar Type
Loadbearing walls and columns S
Exterior, Above Ground Non-loadbearing walls and columns N or S
Parapets, chimneys and masonry veneer N or S
Exterior, At or Below Ground Foundation walls and chimneys S
Loadbearing walls and columns N
Interior
Non-loadbearing walls and columns N
Table 9.20.3.2.-B
Mortar Mix Proportions (by Volume)
Forming Part of Sentence 9.20.3.2.(3)
Mortar Fine Aggregate
Portland Cement Lime Masonry Cement Type N Masonry Cement Type S
Type (damp, loose-state sand)
1 ½ — — 3½ to 4½
S — — — 1 2¼ to 3
½ — 1 — 3½ to 4½
1 1 — — 4½ to 6
N
— — 1 — 2¼ to 3
Table 9.20.3.2.-C
Grout Mix Proportions (by Volume)
Forming Part of Sentence 9.20.3.2.(4)
Portland Cement Lime Fine Aggregate (sand) Coarse Aggregate
2¼ to 3 times the sum of the 1 to 2 times the sum of the cement
1 0 to 1/10
cement and lime volumes and lime volumes
This provision includes a table — formatting is preserved from the source; refer to the official code for the authoritative layout.
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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.