Hydraulic lime will set in damp conditions, and will develop an earlier resistance to frost than non-hydraulic lime mortars. This will depend on how hydraulic the lime is. In choosing hydraulic lime it should be remembered that the mortar should not be stronger or significantly less permeable than the background but should be suitable for the degree of exposure and time of year. This general use guide is indicative only as these products will be suitable for a wide range of backgrounds provided the correct mix ratio is used in the appropriate location and environment.

*NHL 2 Natural Hydraulic Limes:- Used principally to make Mortar Durability Classes 1-4 Depending on ratio of lime to sand, but may be used for all backgrounds depending on exposure.

**NHL 3.5 Natural Hydraulic Lime:- Used principally to make Mortar Durability Classes 3-6 Depending on ratio of lime to sand, but may be used on all but the weakest backgrounds.

***NHL 5 Natural Hydraulic Limes:- Used principally to make Mortar Durability Classes 7-10 Depending on ratio of lime to sand, but may be used for most durable masonry backgrounds.