Thursday, June 14, 2007
Limey---It's All a Wash
Last winter Doug and I were constructing the very last (we swear) building on our property in Moab---a guest bedroom cottage, since our house is pretty tiny. At that time I decided it was necessary to begin learning the art of of Old World lime plastering and limewashing. Several weeks later, after a healthy case of carpal tunnel, I was a convert. I knew that if and when we bought a place in France, these would be skills that would be necessary.
Lime plasterers are a dying breed in the States. Stucco, cement, drywall and latex paint have changed that. The first recorded use of lime plaster dates back 6000 years in Turkey. Its 'breathable' property makes it ideal for both interior and exterior uses, in the harshest and most extreme of climates. What this means is that it releases water vapor as well as that it does not wick water as cement stucco does. It is extremely durable and doesn't crack as it dries.
The recipe for lime plaster is simple: lime and sand. Lime comes from limestone, a sedimentary rock geologically deposited by marine plants and animals. Lime in a powdered form does not occur naturally but must be kilned. The lime powder (les chaux) is mixed with water to re-hydrate it to form a yogurt-thick lime putty that must "age"---anywhere from 1 day to literally years before actually using in the finished product. The longer it sits, the smoother it gets. This may be one of the reasons why lime plaster fell out of favor---it's not an immediate use product.
Lime putty is mixed with varying ratios of sand, with each subsequent coat using less sand. Lime plaster adheres well to stone when it has been wetted down beforehand; and if not, it sucks the moisture out immediately. The pros "hurl" it on and smooth it out with trowels or sponges. There are as many types of finishes as there are old buildings, from rough texture to smooth as silk. Once the lime plaster is exposed to air, the lengthy process of absorbing carbon dioxide begins; according to the limestone cycle the lime plaster will return to it's original CaCO3 state after a few centuries.
After several individual layers of lime plaster, for which the experts have very specific names, you can finish with a color coat, or limewash (badigeon). Color is achieved by adding powdered pigments to a very watered-down lime putty. Unlike popping the lid off a gallon can of latex enamel that you just matched to your color swatch, limewashing is anybody's guessing game. The colorwash dries about 20 shades lighter than when it goes on, so it's incredibly hard to visualize. Plus, lime plaster on one wall accepts limewash differently than another wall.
Limewash has a certain translucency, unlike latex paint. Each additional coat creates more depth without opaqueness. The variations in color only add to its character and charm. Or, at least that's what I told myself. The pigments are natural: earthen oxides, ochres, siennas.
I took the opportunity to limewash a few of the walls in our rez-de-chausse (ground floor) that were bare white plaster while Doug's thumb was recuperating. I was too timid with the pigments at first, and gradually got bolder as I kept telling myself (and Doug) "hey, we'll learn to live with it". With lots of input and encouragement from sister-in-law Leslie, I turned the kitchen into a chemistry lab for several days. The end results are warm and inviting, and I am encouraged to proceed to the next project.
Taking a break from my own limewashing the other day, I was walking through the passageway to Isabel's Midi-Prix epicerie for a few items. I happened upon a limewashing event going on at Andy and Amanda's grande maison on Cours St. Jacques. They were doomed to lose their scaffolding the next day and had quite a bit of work left to do; so I donned my gloves, was thrust a roller and bucket and put to work for several hours. The view from the top level was awesome, and best of all---Doug cooked dinner.