If you don't like dealing with traditional paint, or can't tolerate traditional paint fumes, you can use a limewashing technique to make your own natural wall covering. Not only is it low in fumes, but it's also inexpensive. Perhaps the best part is that by lime washing instead of using traditional paints, you will be a little bit gentler on the environment. Traditional paints have petrochemicals in them, but lime wash does not -- it's an all-natural substitute for paint.
Where to Use Lime Washing
Limewashing can be used both inside and outside your home. It’s been around for thousands of years and traditionally is used to protect the interior and exterior of buildings. At one-time lime wash was considered a poor man’s paint -- it's always been a cheap alternative to traditional paint. Now it's coming back as a “green” alternative to decorate surfaces of the home. An added bonus is that limewash is naturally anti-bacterial, so it prevents the growth of mold.
Compared to traditional paint, lime wash acts more like a stain by soaking into the surface of adobe, brick, wood, and many other substrates. As the limewashed area ages, it evolves into an attractive weathered patina. For this reason, the area you're covering needs to be able to absorb the limewash. Beware that there are some surfaces not compatible for lime, including drywall and already painted surfaces that won’t absorb it, or gypsum plasters, and asbestos cement--both are chemically incompatible. Limewash works best on porous surfaces such as brick, cement block, terracotta, and stone. It can be used on some untreated wood, but remember that since it's a very thin mixture that absorbs, it will draw out the grain of the wood.
How to Make Lime Wash
There are a couple of ways you can make limewash. You can either use Hydrated Lime Type S or lime putty. It's much easier to obtain Hydrated Lime Type S than lime putty, so that is what we will be using for this article. You can get Hydrated Lime at any hardware or home improvement store in the cement aisle.
When making your limewash, use a plastic bucket big enough that you can make enough mixture to cover your entire surface. It's very difficult to make two or three batches that will look and adhere the same. You also want to leave enough empty space at the top of the bucket so there is no spillage. Even though lime wash is environmentally safe, it is very caustic to humans in its wet state and can cause burns. Always wear long sleeves, a dust mask, rubber gloves, and safety goggles.
There is no set recipe for making limewash as every space, wall, and item to be painted is different. So instead of paying attention to ratios, pay attention to the consistency. Add powders to water very slowly, not the other way around (if you add the water to the powder it can create dust which should not be inhaled). Combine the powder and water with a plastic spoon or other utensil. Your bucket of limewash should have the consistency of milk. Anything thicker will not adhere well and will look more like a plaster than a lime wash. If you are unsure how much water to start with, try making a smaller batch just to see how much water and lime it takes to make a milky consistency. Then double or triple your recipe, depending on how big of an area you are painting.
To keep things natural, there are "organic" pigments you can add to the wash to get some color. Beet juice and red or gray clay will add some color. You can even use spices like turmeric or saffron to give your mixture a yellowish-orange tint. Cinnamon gives a great brown tint. If using a powdered pigment, mix it with hot water first in an average ratio of 20:1. Of course, the more pigment you add to the water, the deeper the color. When you have your desired shade keep in mind that it will be diluted in the limewash mixture and stir the color slowly into the limewash.
Limewash needs to be applied to a damp surface. The best way to achieve this is to spray the surface with a water mister. To apply, you can either use a large, rough-textured brush or a drywall sponge. You may need up to 3 or 4 coats to achieve your desired look. Each coat needs to dry before adding another on top, and the surface needs to be damped with a spray bottle each time. Remember to keep your rubber gloves on, especially if you are sponging the limewash on.
Let the area dry for at least three days after the final coat before touching the wall (or hanging anything on it). Limewash doesn’t look like much when it's wet, but it gets better as it dries. Drying conditions need to be favorable for it. If the humidity is too low, or the heat is too high it can cause the coat to dry too fast. Limewash needs to dry slowly.
There's no need to wash walls with a limewash finish -- just give them a fresh coat! It will need it anyway after about five years.
Limewashing Pros and Cons
Deters woodboring beetles
Is a natural fungicide
Is inexpensive and solvent-free
No need to wash the walls - just apply refresh coat
Cleans up with soap and water
Difficult to match batches (so make all you need in one batch)
Better in slow drying conditions (above 40 degrees, below 75 degrees, and not when the sun is hitting the area)
Should be renewed about every 5 years
Can leave a chalky residue that will rub off on clothing (there are additives to reduce this, but none that are environmentally-friendly)
Limewashing is a great way to "faux paint" your walls, cement or block foundations and anything else that will absorb it. It can even be used on terracotta planters. Best of all, it's not toxic to the environment!