Natural Lime Mortars in Very exposed areas

St Astier Natural Hydraulic Limes (NHL)

Site mixed mortars

NHL 5 mortars.
Binder / sand ratio 1: 2. Use clean, well graded sands 0-3mm

NHL 5 has moderate free lime content (around 22%) and there is less risk of lime leaching if the mortar has had the time to achieve its matrix before being exposed to heavy rain.
In pointing work, attention should be paid to moisture within the structure. Dampness will prolong the carbonation of the free lime content and therefore the time for the mortar to achieve the required strength and structure. The free lime can also go into solution and leach out.

NHL 3.5 mortars.
These can be used but will require some more time to achieve the required strength and structure. Binder/sand ratio 1 : 2.

Ready mixed mortars

EcoMortar 3.5 CG for bedding
EcoMortar 3.5 G or F for pointing

The use of Ecomortar is similar to the NHL 3.5 mortars

Moderate and normal exposure areas

Site mixed mortars
NHL 5 or NHL 3.5 binder / sand ratio 1: 2.5, Use clean, well graded sands 0-3mm.

Ready mixed mortars
EcoMortar 3.5 CG for bedding
EcoMortar 3.5 G or F for pointing

NHL 2 Mortars: generally not recommended for this type of work in very exposed or moderate exposed areas unless applied between March and early September and protected against heavy rain exposure for several weeks.