Anti-Microbial, Anti- Bacterial, Pro Clean Air

What makes lime plaster such a great choice for interior walls in our homes? Beauty is the obvious choice, but the benefits we receive from limes inherent properties are valuable in regard to health, indoor air-qualilty and cleaning regimine. We'll go thru some of the benefits that we get when we choose this timeless finish.

First stop in controlling the various types of micro flora and fauna that can grow in the home is humidty. Perhaps the best benefit of a lime plaster surface (or clay plaster surface for that matter) is that it is naturally hygroscopic, it seeks out water molecules from the environment and holds onto them, to a point. There is a constant dance of moisture moving into and out of the plaster depending on how dry or wet the air is relative to the saturation point of the plaster. This moisture dance acts as a buffer in the relative humidity of a homes air. It naturally lends itself to keeping the air from having enough moisture in it to support rampant microbial growth on surfaces or in the small particulate floating in the air. It helps keep the air from overly drying out which is more comfortable for us as humans.

Secondly, lime has a realtively high pH. The wet lime has an extrodinarily high pH, like 12 plus depending on the lime. This is why when we are handling and installing lime you'll see installers wearing gloves and even eyewear. The wet limes pH is so high it can burn skin if you are working with it and really be harmful to eyes. Once it dries and turns back into limestone, the pH is still very basic, 9.9 in fact. This pH creates a very hostile environment for mold, fungi, bacterial and virus to try and grow. A high pH like this physcially tears the cells of small organisms apart and prevents them from living and growing, it is the same function soap has on micro organisms when we wash our hands. If mold, mildew, viruses and bacteria can't grow on the plastered lime surface they are not able to become air bourne and harm our air quality in the first place. The micro-organisms that do find there way onto the wall are often destroyed by the pH, almost like the walls are scrubbing the air.

The two above benefits are key to making lime plaster in a shower such a superior choice. When we add an olive-oil based soap to a lime plaster as it is curing we create a layer that is actually hydrophic, calcium stearate, it repels water. This gives the plaster the ability to repel liquid water while still being able to move water vapor in and out of its surface, it remains breathable. The surface is ideal in everyway for a shower, less or no mold and mildew, less need for cleaning and no need for harsh chemical cleaners as well as buffering the humidity created by showers.

Lastly, lime benefits us by what it is and what it is not. Lime, calcium carbonate is chemically the same as limestone, which is relatively benign to us as a material. It is not a petroleum by-product, does not need a petroleum-based solvent, and it does not require additives to make it class A1 fire rated or anti-microbial. Synthetic modern day finishes use some or all of these additives to meet building codes and perform in a way that is beneficial. Lime does all this as part of its nature, while creating better air quaity for us while synthetic counterparts actually contribute to poorer indoor air quality. Is there a better indoor surface? Perhaps, I haven't been shown it yet.