This feebly Hydraulic lime can be used in the consolidation of frail historic masonry. This lime produces a high modulus of elasticity, useful when fine sand is added to make interior finish coats of lime plaster.
NHL 2 can be used to make very soft pointing mortars for repairing around friable historic masonry especially when the wicking away of water is beneficial. Though similar to lime putty in many of its properties, NHL 2 has the advantage of setting with both air and water reaching a set in approximately in four days. Traditional lime putty sets slowly, with air, over a period of six weeks. Cured NHL 2 is about as hard as a piece of chalkboard chalk in the first week. Mixes containing NHL 2 and 1-3 % casein powder can make an injection grout that will flow into every cavity behind plaster or brick collar joints. This fits if you are considering exterior historic stucco reattachment. Grout injections with NHL 2 can be used to stabilize masonry or brick before repointing.
Consider using casein as the catalyst to increase flow rather than pulverized fly ash (PFA). Tests done on lime mortars modified with PFA suggest run-away strengths may continually increase with ongoing densification of the lime / PFA grout. This increased densification can trap moisture in cavities. ”