Lime mortar, traditionally used by our ancestors to bind stone to stone in the building of bridges, lighthouses, homes and monasteries, was suddenly displaced by the arrival of cement in the early 1900’s.
On the face of it, cement had much to offer with its quickly hardening properties. Lime was cast aside.
Seventy years later and with the benefit of hindsight we see what a mistake this was, with the demise of our vernacular architecture speeded not least by the unsuitability of cement to our stone buildings.
Stone needs to move and settle within a structure. Cement once dried is too brittle to allow movement; hence cracks appear to accommodate expansion. Once cracked, moisture gets trapped within the wall and even within the stone.
Also Lime is permeable – it allows stone to breathe, so that water that gets into the wall doesn’t get locked inside but can get back out again through evaporation.
Up and down the length of Ireland we see cottages that have fallen to rack and ruin. Many have been rendered in cement.
Had we known the drawbacks and stuck with lime, many of these buildings would still be serviceable homes today. As it stands our cottages are dwindling at a frightening rate.