Why use lime?
Why should we continue to use lime in the late twentieth and early twenty-first centuries? As a construction mortar, from mass foundations to walls, arches and vaults, lime is resilient and flexible, adjusting to minor settlement and accommodating thermal movement. It is ideal for structural repairs to lime-built masonry buildings. For repairs and repointing of masonry work, lime mortar can be matched to the density of the stone (or brick), to minimise the risks of salt damage and stone decay. The use of lime mortar in wall cores, in joints and on the face of the wall assists in the exclusion of driving rain by ‘mopping up’ free water before it can penetrate to the building interior and encouraging re-evaporation to the outside air. As an external weathering coat, lime mortars in the form of harling or rendering, can provide a more effective coating than cement-based materials. Good lime coatings do not suffer from the micro-cracking almost always present in cement-based coatings and,
Two main reasons for using Lime products in building: • Lime is slightly flexible. This means that day-to-day thermal movements and longer-term settlement can be accommodated without cracking the bricks or stone. • Lime is breathable. Water and vapour can escape from the building instead of being trapped and causing damage. Lime has many other benefits for the building and also for the environment. The Building Limes Forum website has more information on these benefits.
