Heidelberg Natural Hydraulic Lime NHL 3.5 White - 25kg (SKU: 92868)

Natural Hydraulic Lime as a constituent of lime-sand mortars can be used for a wide range of applications for jointing mortars, bedding tiles, renders and plasters. Using suitable sharp sand the mortar will have excellent workability and good water retention when applied to most bricks, blocks and surfaces to be bedded, rendered or plastered. The lower strength of natural hydraulic lime mortar compared with Portland cement based mortars allows mixes to be produced which complement the lower strengths of many natural stone and soft brick applications whilst improving plasticity and retaining a high level of cohesion with low shrinkage.

Natural Hydraulic Lime NHL 3,5 moderately hydraulic lime is produced to meet the requirements for mortar, render and plaster for conservation, restoration and new build construction. It conforms to the requirements of BS EN 459-1 type NHL Natural Hydraulic Lime strength class 3,5.

This NHL is suitable for use in lime:-sand mortars for stone, tile, brick and block laying, external rendering and internal plastering. It provides options for the whole range of climatic conditions encountered in the UK. NHL is particularly useful in designing mortars and renders to complement the strength of natural stone and soft brick construction. The high degree of whiteness facilitates production of quality architectural finishes and can be pigmented to supplement sand colours and provide matches for restoration work.

Very high strength is not normally required of NHL building mortars. 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 natural hydraulic lime mortar imparts special properties to mortar such as low shrinkage combined with elasticity and allows cracks to heal autogenously by continuing carbonation.