Plasters and Humidity

We have mentioned that natural plasters are the best wall covering option for controlling indoor air quality. Learn more about how lime and clay plasters help manage indoor humidity levels, any why that is important for your health.

Why is indoor humidity a factor in air quality?

The idea of improving indoor air quality might seem like a lot to take on. Obviously, we should take chemical-smelling objects out of our homes, and try to reduce smoke or use a fan when cooking. But managing humidity? It might not be clear why that is important.

Too high humidity….

If indoor humidity is too high, it will lead to many problems. One is condensation, which can occur on cold surfaces, like windows. However, this condensation can also occur on less visible places, like within the wall. When all this moisture builds up over time, that can lead to mold, rot, and eventually structural problems.

High humidity also leads to health issues in building residents, due to increased presence of mold spores, fungi, mites, and even viruses in the air you breathe. Additionally, high humidity indoors lead to other building materials “off-gassing,” or releasing toxic chemicals that were used in their manufacture, at a higher rate. This will worsen the air quality further. Eventually, if high humidity goes unmitigated, you will need to undertake major renovations to remove mold and other toxins, and make the home healthy and structurally sound again.

Too low humidity…

Conversely, if indoor humidity is too low, you may not feel comfortable in your home. Dry air makes you feel cold, because moisture evaporates from your skin faster. Therefore, you end up spending more money on heating costs. Depending on your heat source, the heat can dry the air out even more. This will cause discomfort and health issues in your respiratory system, and dry, uncomfortable eyes and skin.

Clay (and lime) plasters help manage indoor humidity.

Natural plasters are able to absorb humidity from the air when there is a high level of humidity, and then release it slowly back into the home when humidity levels drop. This levels out fluctuations in humidity. The result is a more constant level of humidity, regardless of temperature and environmental conditions. Also, all of the moisture that is absorbed by your plaster will not be condensing on another building material that could be subject to mold. Clay and lime plaster are naturally mold resistant.

This video from American Clay does a great job of explaining and demonstrating how clay plaster is able to absorb excess humidity.