Burning , slaking and sieving the lime

Mortars for re pointing should be softer than the masonry units and no harder than the historic mortar to prevent damage to the masonry units. Stresses caused by natural conditions should be relieved by the mortar rather than the by the masonry units. Stresses caused by mortars, which are too hard, can break the bond between the units and the mortar; they can also cause cracking and spalling of the units.

The process involves burning , slaking and sieving the lime. ( Want to know, How ? )

Lime mortar is soft, porous, and changes little in volume during temperature fluctuations thus making it a good choice for historic buildings. Because of these qualities, high calcium lime mortar may be considered for many re pointing projects, not just those involving historic buildings.

This mortar inherently possesses very low compressive strength, attaining between 50-300 psi in 28 days. This low strength is beneficial in allowing the masonry walls to "flex" without cracking.

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