Until the twentieth century,
lime was the principal cementing agent used in building construction,
being used exclusively in cements, mortars and plasters. With the
advent of quick setting additives like Portland cement and gypsum,
pure lime plasters have largely fallen into disuse. There are many
advantages to using pure lime plasters. Including weather resistance,
breathability, durability, and flexibility.
In an amazing chemical
transformation, ordinary limestone (CaCo3) is heated to
a high temperature, releasing the carbon and producing quicklime
combined with water, a violent chemical reaction occurs, boiling the
water and producing hydrated lime (CaOH). Hydrated lime
is mixed with water to form lime putty. Lime putty is then mixed with
an inert aggregate, such as sand or gravel to form a mortar or
plaster.When exposed to the atmosphere, the lime putty (CaOH)
combines with free carbon molecules from the atmosphere in a
slow process called carbonation. The chemical reaction which occurs
produces crystals of calcite (CaCo3) or
limestone. These crystals are unusual in that they have a dual
refractive index; light entering each crystal is reflected back in
duplicate. This results in the wonderful surface glow that is
characteristic of lime plastered surfaces, and is not found in other
Lime based plasters can be made to many different specifications and levels of refinement. From very rough thrown on exterior coats to glass like venetian plasters made with marble dust and applied in multiple paper thin coats. Lime plasters can be colored with a wide variety of natural pigments and an amazing array of glowing colored finishes can be achieved.
Historically, lime wash is one of the oldest and most widely used paints in the world. As lime technology developed, it was discovered that a thin coating of lime mixed with water could be applied to almost any surface and create a thin protective coating of limestone. Durable and breathable, and because of its alkalinity, highly antiseptic, limewash became the universal coating used to protect buildings of earth and stone throughout the world. From the glowing white domes and vaults of Greece and Morocco to the Ocher walls of Tuscany and Venice to the minarets of Tehran and Baghdad.
In many cultures, limewashing became an annual tradition. The whole village would turn out, usually at the end of the rainy season and apply a fresh coat of limewash to all the buildings, providing another year of glowing protection from the elements.
of the light reflecting qualities of lime, limewashed buildings
appear to glow in all types of light. Limewashes are known to age
gracefully and seem to become more enchanting as time takes its toll