Hydraulic lime (HL) is a general term for calcium oxide, a variety of lime also called quicklime, that sets by hydration. Can be used for both the conservation and renovation of historic buildings, and in new build applications. Mortars made with natural hydraulic lime gain strength by a combination of hydraulic setting and carbonation. The lower strength and greater permeability of natural hydraulic lime mortars when compared with cement-based mortars is particularly suitable for repairs to older buildings and for traditional style. Natural hydraulic lime mortars have good workability and plasticity and can accommodate some differential movement within the building.