Lime and clay finishes contribute significantly to the overall integrity of space beyond just aesthetic appeal and durability. As the reality of climate change sets into everyday life, there has been a global refocus back to natural and environmentally-friendly building materials. Whereas traditional and ancient techniques promoted breathability and flexibility throughout a structure, contemporary building practices tend to lean towards rigidity and impermeability from the elements. The potential for modern eco-friendly building construction is a marriage of the two systems, playing upon contemporary energy-efficient elements and traditional humidity-regulating building practices. The incorporation of materials such as lime and clay plasters can have a number of environmental benefits, for the structure, its inhabitants, and the building’s carbon footprint.
The primary benefit of using lime and clay products is that they are sourced from the earth with minimal intervention by synthetic materials. Modern building materials such as paints, varnishes, manufactured woods, polymer cement and drywall compounds can include toxic chemical additives within their makeup. Such materials can emit what is known as Volatile Organic Compounds, or VOCs. These are pollutants that are released as a gas from solid or liquid substances and carry a variety of short and long-term adverse health effects, such as the exacerbation of respiratory disorders and allergic reactions. This becomes concerning as human beings increasingly spend more of their time indoors, so lime and clay plasters are appealing not only for their aesthetic, and functionality but from a health and well-being standpoint as well.
Natural plasters, like lime plaster, contain none of these toxins and in fact, inherently promote a cleaner air environment within the space. They are porous and permeable in nature, allowing for moisture to be held within their membrane to either pass through or be released back into the atmosphere when conditions allow. Known to be humidity regulators, clay and lime materials ‘breathe’ in that they can draw in moisture from external sources, such as rainwater, or internal sources like showers and cooking steam in order to maintain an environment that is not too moist or too dry. Moisture management is one of the greatest issues in a contemporary building, in that materials such as paints and synthetic stucco act more to exclude moisture altogether. And yet, when there is an inevitable introduction of moisture into the environment it then becomes trapped as these modern materials are impermeable and do not allow the moisture to be released. Thus the use of lime and clay plasters both on the interiors and exteriors of building structures help to prevent moisture-related issues such as mildew, mould, and rot development.
It is true that older buildings tend to allow excessive air movement within the structure, whether that be from chimneys or drafts around windows and doorways. Current insulation practices have allowed for modern buildings to be more efficient, reducing energy costs when it comes to heating and electrical usage. However, there must be a balance between the two and natural plasters help to achieve that. Clay & Lime Renders, Plasters & Paints (2008) by Katy Bryce and Adam Weismann liken the use of natural plasters to a ‘third skin’; where our actual skin and clothing come first and second to protect us, the structure serves to shelter us from the elements while still contributing to our livelihood and happiness. Natural plasters serve that purpose aesthetically and practically, simultaneously creating less of an impact upon the surrounding environment than their contemporary counterparts.
Whether you wish to outfit an entire exterior or interior in natural plaster or to select a single wall, floor, or feature for its application, you cannot go wrong. Lime and clay finishes contribute much more than just decorative appeal and durability when it comes to the total integrity of the space. If building for the environment and for human health is a concern, then look no further than natural plaster.