Heidelberg Hydrated Lime - 25kg (SKU: 92867)

Hydrated Lime improves the plasticity, cohesiveness and water retention of Portland cement mortars and renders and can be used for a wide range of building applications. As hydrated lime is non-hydraulic, it is not suitable for use in mortars and renders without a Portland cement being present.

The key benefit of Hydrated Lime is its effect of improving the workability and water retention of mortars and renders when used as a lime putty. A lime putty can be produced by adding an excess of Hydrated Lime to clean water in a container, while constantly stirring to 

form a paste. The paste should be allowed to ‘condition’ by standing for at least 24 hours before use. It is essential that the paste is not allowed to dry out during this time.

Hydrated Lime is a quality-assured, non-hydraulic hydrated lime produced to meet the requirements for mortar, render and plaster for conservation, restoration and new build construction. It conforms to the high calcium requirements of BS EN 459-1 classification CL 

90-S.

Hydrated Lime is manufactured by calcining a high purity calcium limestone in carefully controlled conditions. This process produces quicklime which is then crushed, hydrated and re-ground to produce the finished fine powder.

An unnecessarily strong mortar will concentrate the effects of any differential movement between the mortar and the masonry and cracks may appear which could reduce the durability and increase the risk of penetration by rain. A weaker mortar will accommodate some differential movement between the mortar and the masonry and if cracking does appear it will generally be distributed as hairline cracks in joints, thus preserving the integrity of the stone, bricks or blocks themselves. 

In general mortar should be weaker than the masonry it is used with. The use of Hydrated Lime imparts special properties to mortar of low shrinkage combined with elasticity and allows cracks to heal autogenously by continuing carbonation.