Lime plaster Lime plaster Lime plaster is a type of plaster composed of sand, water, and lime, usually non-hydraulic hydrated lime (also known as slaked lime, high calcium lime or air lime). Ancient lime plaster often contained horse hair for reinforcement and pozzolan additives to reduce the working time. Traditional non-hydraulic hydrated lime only sets through carbonatation when the plaster is kept moist and access of CO from the air is possible. It will not set when submersed in water. When a very thick layer or several layers are applied, the lime can remain soft for weeks. The curing time of lime
Lime mortar or other aggregate. The addition of cement or other pozzolan to decrease cure times is referred to as “gauging.” Other than Portland, ash and brick dust have been used to gauge mortars. For historic restoration purposes, and restoration work involving repointing or brick replacement, masons must discover the original brick and mortar and repair it with a similar material. The National Park Service provides guidance for proper masonry repointing through Preservation Brief 2. In general, Brief 2 suggests that repointing should be done with a similar or weaker mortar. Therefore, a straight lime mortar joint should be repointed in kind.