This nonhydraulic binder is best suited for interior lime plaster as it is soft and very permeable, cures slowly and doesn’t withstand extreme weather or significant exposure.
NOTE: “Lime putty” is often used as a generic term for lime mortar, but this is a misnomer; lime putty is in fact a specific type of nonhydraulic lime that has been slaked from quicklime and is aged to achieve a texture that is similar to sour cream.
We are very cautious with lime putty mortar. Its high vapor permeability and low strength are well suited to historic buildings with friable masonry, but we have many concerns about durability and long-term performance in most climates due to its long carbonation cycle. In areas with cold conditions lime putty is susceptible to frost and freeze damage since it is unlikely to have fully carbonated before winter, even if it was installed during the previous spring.
Niagara Lime Putty Datasheet