12 April 2026
Lime mortar is softer and more vapour-permeable than cement. On older masonry, that lets the wall breathe and move without cracking the bricks themselves. Cement mortar, by contrast, is hard and impermeable — bricks become the sacrificial element and start to spall at the face.
Older houses were built with solid walls and no damp-proof course or cavity. They manage moisture by absorbing it and letting it evaporate, mostly through the joints. Seal those joints with hard cement and the water is forced out through the bricks instead, carrying salts and causing frost damage and damp inside.
As a rule of thumb: anything built before about 1919, anything listed, and anything in a conservation area should be repointed in lime. That covers a lot of East Sussex — Victorian terraces in Eastbourne and Hastings, Regency Brighton and village cottages across the Weald. For post-1919 properties a properly specified cement-lime-sand mix is usually appropriate.
Lime work also needs more care: correct sand, slower working and protection while it cures. Done properly, it lasts for decades and can be renewed without damaging the brick. We diagnose on the survey rather than defaulting to one or the other.