Lime mortar lime putty when mixed at a 1 to 3 ratio, fill these voids to create a compact mortar. Analysis of mortar samples from historic buildings typically indicates a higher ratio of around 1 part lime to 2 part aggregate/sand was commonly used. A traditional coarse plaster mix also had horse hair added for reinforcing and control of shrinkage, important when plastering to wooden laths and for base (or dubbing) coats onto uneven surfaces such as stone walls where the mortar is often applied in thicker coats to compensate for the irregular surface levels. If shrinkage and cracking of the lime
Lime (material) a form of calcium carbonate. Selenitic lime, also known as Scotts' cement after Henry Young Darracott Scott is a cement of grey chalk or similar lime, such as in the Lias Group, with about 5% added gypsum plaster (calcined gypsum). Selenite is a type of gypsum, but selenitic cement may be made using any form of sulfate or sulfuric acid. Sulphate arrests slaking, causes the cement to set quickly and stronger. The Romans made concrete by mixing lime and volcanic rock to create a pozzolanic reaction. For underwater structures, lime and volcanic ash were mixed to form mortar, and this