Lime mortar is a type of building material made from a mixture of lime, water, and an aggregate like sand. It has been used for centuries in construction due to its flexibility, breathability, and ability to set slowly, allowing for adjustments during application. Lime mortar is particularly valued in the restoration of historic buildings, as it is compatible with older materials. Unlike modern cement, lime mortar can absorb and release moisture, which helps prevent damage to masonry. It is also more environmentally friendly, as it produces less carbon dioxide during production. Overall, lime mortar is a sustainable choice for both new and restoration projects.