Lime has been used for thousands of years in building construction, such as plasters, mortar, paints or washes. It is breathable, carbon neutral, and naturally mold resistant. The process involves mixing bagged lime, which is made of limestone that was burned in a kiln and water.
Carbon dioxide from the air causes lime putty to harden, so it is important to store it with an inch or so of water on top until its ready for use. We poured 6 bags of lime into a barrel that was filled halfway with water and mixed with an electric mixer. The longer the lime putty sits before use, the better (at least 2 months).