Once you’ve seen an authentic lime washed wall, you’ll remember it. Touch a smooth lime plaster wall and you’ll remember it. There is something about its sleek, creamy feel… If you’ve traveled in Italy or France or Mexico, chances are that you’ve seen these mottled, weathered, lime plaster walls.
They seem as hard as stone and that is because they are.
Lime based plasters and paints are mixed with natural pigments only. The pigments must be suitable to mix with the lime or they will not remain stable and fade over time.
Lime plaster has been used for thousands of years. The entire process is long and involved. Limestone is “cooked” until the chunks disintegrate and become a powder known as calcium oxide. This lime powder is then mixed with water and left to slowly age or “slake”. It is this slaked lime, in a putty form, that is mixed with varying amounts of marble dust and sand. The pigments are added at this time. In this day and age, other ingredients are often added to the lime plaster mix.
Generally, several layers are applied to the walls. As the lime dries, the water is absorbed into the wall and the carbon dioxide “slakes” the lime, rendering the material back to limestone. And it is as hard as stone.
Applying lime plasters directly to a latex or alkyd (otherwise known as oil based) painted wall will not work; lime plasters and paints need to have a special base that allows the lime to adhere to it.
Lime washes are created by mixing the lime putty with water to a milky consistency and applying the wash with a brush. It has a faded, almost pastel look, that appears authentically weathered. Lime based paints are generally used to let the walls “breathe” rather than locking in humidity. They are excellent for bathrooms and kitchens as they are a deterrent to mold.