Description: Natural hydraulic lime (NHL). A comprehensive guide to the types of building lime to use. Information and technical advice
This site aims to demystify the topic and provide the necessary guidance so you can make the right choice of lime binder, correct sand and the appropriate mix.
Natural hydraulic lime or NHL , comes from limestone that has natural impurities of clay and other minerals.
There are three European classifications: NHL 2, NHL 3.5 and NHL 5 based on the compressive strength of laboratory mortars after 28 days. These are often somewhat misleadingly termed feebly hydraulic, moderately hydraulic and eminently hydraulic.