How to Insulate Older, Stone and Century Homes in Guelph

Guelph earned the name Royal City partly for its handsome grey stone buildings, and the same local stone was used for homes, churches and mills across Wellington County, from Elora and Fergus to Rockwood. Galt in Cambridge has a similar stone heritage along the Grand River. Many of those houses are 120 to 180 years old, still lived in, still full of character and still cold every winter.

Insulating an old stone or solid brick house is not the same as insulating a modern wood-framed one. Solid masonry walls rely on warmth from inside to stay dry, and the wrong insulation in the wrong order can trap moisture in the stone, rot joist ends and damage mortar through freeze-thaw cycles. The good news is that most of the heat loss in these homes can be fixed without touching the walls at all.

This guide from the certified installers at Super Sprayers explains how solid masonry behaves, the safer order for upgrades, the options for stone walls when you do want to insulate them, the surprises old houses hide and how heritage designations affect the work. It applies equally to limestone, fieldstone and double-brick homes, and to the stone foundations under many later frame houses.