The Ontario Building Code | Mortar for Chimney Liners

9.21.3.9. mortar for Chimney liners

(1) Chimney liners used in chimneysfor solid fuel-burning appliances shall be laid in a full bed of,

(a) high temperature cement mortar conforming to CAN/cgsb-10.3, "Air Setting Refractory mortar", or

(b) mortar consisting of one part Portland cement to three parts sand by volume.

(2) Chimney liners used in chimneysfor oil- or gas-burning appliances shall be laid in a full bed of mortar consisting of one part Portland cement to three parts sand by volume.