Lime based plasters

Lime plasters are derived from hydrated lime, or lime grasello. Grassello is the result of a process where mined limestone is fired in a kiln in order to extract all of the moisture contained within the stone. From there you have a very dry, lightweight stone that is easily ground into a powder. The powder is re-hydrated with water. This process makes a very soupy mixture. The soupy mixture is then laid to rest or aged for 6 months to a year. During the aging process, the lime powder drinks in the water and becomes the consistency of stiff modeling clay.

At this point, the grasello is shipped from the manufacturing plant to the refining plant (Safra). Safra then modifies the grassello into the plasters that we use today. Adding sand makes Prontomuro. Calcenova is filtered of all grit and impurity. Marmorino is grassello infused with marble flour.

Historically, the grasello was aged in the ground. Families would bury the grassello and use it at their own discretion. The longer grassello is aged, the better it is. From time to time, buried grassello pits are still found in Italy.

The grassello that is used in our lime plasters is aged for about nine months. The limestone that is used to make our grassello is primarily mined out of the Italian Alps. It is nice to think that every time we apply a lime plaster to a home, we are literally giving the homeowner a piece of Italy and its history.

The qualities of a true lime plaster are as follows. Lime plaster is made from lime grasello. Lime plaster is an aerial lime; hardens slowly when exposed to air. Lime plasters allow the substrate to breathe. Lime plasters are completely organic and prohibit the growth of bacteria.