limesand

Limesand is a traditional building material formed by combining a lime-based binder with an aggregate of sand to produce mortar, plaster, or render. The binder is typically lime putty, prepared from slaked lime, or hydraulic lime that sets through hydration. The sand provides the granular filler and body to the mix. Proportions vary by application and climate, but common mixes range roughly from one part lime to two to four parts sand.

Production and varieties: Lime-putty mortars are made by mixing mature lime putty with sand and allowing slow carbonation for strength. Hydraulic lime mortars include pozzolanic materials or impurities that impart a hydraulic set, enabling earlier strength in damp conditions. The sand is washed and graded to remove fines that might weaken the mortar. The result is a porous, flexible, breathable material that accommodates minor substrate movement.

Uses and properties: Limesand has long been used in historic masonry, lime plaster, and render, particularly on brick, stone, and timber-framed structures. It is valued for vapor permeability, elasticity, and compatibility with porous substrates, reducing the risk of trapped moisture and salt damage. It requires gradual curing and protection from rapid drying.

History and modern use: Limesand dates to traditional European construction and remains favored in conservation work and in new-builds that aim to resemble traditional techniques. It supports energy-efficient walls and is often part of lime-based restoration products used in restoration and sympathetic new construction.