Why is mortar falling out of my stone house in Manotick?

Mortar falls out of stone walls for a few reasons, and a mason looking at your wall is the only one who can say which applies to yours. The NRC building digest CBD-123 notes that a "crows-foot pattern on the surface of a mortar joint indicates freezing," and that "shelling of the mortar surface and general crumbling or powdering of mortar are evidence of advanced deterioration due to freezing."

What a mason will look at includes the condition of the remaining joints, whether the stone itself shows any damage, where on the wall the loss is concentrated, and whether there are signs of moisture getting behind the wall. The answers shape both the repair method and the mortar choice. The Centretown Heritage Conservation District plan notes that "lime-based mortar should be used when repointing historic brick and masonry as cement mortar prevents moisture from escaping through the mortar and causes brick damage," and that "using a mason experienced in lime-based mortar is encouraged." That plan applies in Centretown; if your property is designated or in another heritage conservation district, check its own plan or designation by-law before work starts.

For the repair itself, published Ontario contractor pricing for 2025-26 puts repointing at about $10 to $30 per sq ft of wall, with the middle of the published ranges at about $15 to $25. Heritage lime-mortar repointing runs about $15 to $45 per sq ft. Your quote will differ depending on how much wall is affected, whether scaffolding is needed for upper sections, the mortar type and colour match required, and how the old joints are removed.

When cutting or grinding out deteriorated joints, silica dust is a regulated workplace hazard. Ask the crew how they will control dust on site, such as wet cutting, dust extraction or respirators.

Ask for the mortar specification in writing as part of the quote.