Hydraulic Lime NHL 3.5 - 25kg
Hydraulic Lime 25kg
Natural Hydraulic Lime NHL 3.5 is typically used for external repointing, rendering and building works on most masonry types.
We recommend using lime mortar for all our limestone walling products. It creates a mortar which is softer than the stone, allows the stone to 'breathe' and has visual advantages over standard grey OPC mortar.
A guide on best practice when working with lime mortar is available to download here: Best Practice Guide
WHY USE LIME MORTAR?
Traditional mortars were made from lime and sand and/or other coarse aggregates, sometimes with additives such as brick or coal dust. The pointing acted as a ‘sacrificial material’ so that moisture within the wall would be drawn through the joint and evaporate, instead of through the brick or stone. The use of lime - a porous material - allowed the building to ‘breathe’.
Modern mortars tend to be cement-based, and are usually harder than the surrounding brick and stone, and are impervious unlike lime mortars. This means that moisture is not transferred through the pointing, but through the brick and stone. When this freezes, the brick and stone decays instead of the pointing, leading to difficult and costly repairs, not to mention causing damage to the appearance of the building. Another common problem is that water can freeze behind cement pointing and force it out. When this happens, the arrisses (edges) of the stone or brick are likely to break away, leaving joints exposed and spoiling the appearance of the wall.
Pointing for traditional buildings should always be lime-based, mixed to match the original mortar as closely as possible in colour and texture.
