Put a little Art into it.
After a layer of brown coat, we were ready to add some bling. Local artist Susan Peterson came to the rescue with her sketching skills and helped create our oak tree outline. The oak tree is a powerhouse, or I should say, keystone species, in our ecosystem. So many species depend on the oak for survival, that it’s value in our area cannot be overstated. It’s slow growing, but strong. It’s both rugged and beautiful at the same time. Be an oak, I say.
Our oak tree was formed with a cob mixture using chipped straw. Initially I added screws as anchors to secure the new cob layer to the older dry layer. But as we got more confident with the cob, I realized this wasn’t necessary. It is necessary to wet the older, dry layer and add slip to help the cob adhere. We added layers to create depth in the bark of the tree and used our fingers to shape the grooves. It’s an incredible satisfying experience. We added another brown coat to our creation, and we were ready for lime.
Add a Dash of Slaked Lime
I don’t even know why Menards carries lime. Just try to ask an employee where it is and you get a look like this: But thankfully they carry it, and it’s cheap. It’s Hydrated Type S lime and you will leave the store dusted in it, I promise. This step takes some planning ahead since the so called hydrated lime actually needs to be hydrated in a process called slaking. You add the lime to water. I used the same barrels I used for the slip. It’s a very fine caustic powder, so I recommend using a mask to prevent inhaling it whenever working with powdered lime. I added enough water to cover the lime completely, using the water to create an airtight seal to prevent the lime from hardening. And then you let it sit. The longer the better. Sources I found recommended 30 days. 7 as a minimum. 1 yr, even better.
Our lime was mixed with a fine sand and cattail fluff to form a plaster that is more water resistant than cob. I used the paddle mixer and drill to prepare the mix, adding 3 parts lime to 2 parts sand and enough cattail fluff to create a thickness that wasn’t runny. I added no pigment to the first layer, so our cob house was temporarily white. We wore gloves and applied the plaster by hand to create an even coat, but took care not to smooth the first layer so there was enough grip for the final layer.
Dye options are limited for the lime plaster. Due to the high ph, natural plant material dyes aren’t an option. You need concrete dyes or mineral dyes. Menards carries concrete dyes in neutral, earthy tones like beiges, brick reds, and browns. I did a test patch of the dye options and was surprised how pastel some of the colors looked. I chose tan for the majority of the walls.
After the first batch of plaster, I realized the massive amounts of dye that would be required to get the color I wanted. I quickly turned to the fresco painting technique. This was the type of painting Michelangelo used in the Sistine Chapel (which gave me a whole new respect for his work!!) Fresh lime plaster is spread and partially dries (we are talking minutes to a couple hours here). Don’t leave the job site, because once it’s too dry it isn’t happening. When the lime plaster is leather hard, you brush the pigment into the plaster. As the plaster hards, the pigment becomes integrated with the plaster, unlike a paint that rests on top. It’s not the process to use if you want a uniform color, but I found the variations in the coloring very appealing. Another plus is that this method used very little pigment!
The Earth Laughs in Flowers
I saved the interior finish for last because it was a huge blank slate for a message to share. I sought out local artist Linda Doyle for inspiration on this design. She creates incredibly beautiful botanical designs with multimedia and is delightful to work with. Knowing my draw to native plants, she created a design for wildflowers growing out of our interior bench. I couldn’t wait to get started!!!
We tackled the bench first. We used the fresco painting technique with a chocolate brown mineral dye. I didn’t love how it looked after it dried–splotchy and inconsistent. But after using a rag to create some more evenness, I fell in love with the new look! It looked like soil with roots running through it which was the perfect base for our next step–the flowers!
We made a mixture of slaked lime and plaster of Paris. The mixture dries out quickly, so small quantities are best. We used spray bottles to wet the surface we were wanting to adhere the plaster to and used our fingers to firmly press it into the wall. We then added subsequent layers to build out the parts of the flowers, keeping our work area small and manageable so we could add pigment before the quick drying plaster dried. This process happened so fast that I didn’t have time for pics. Or maybe Linda and I were *that* immersed in our work. I had purchased a set of powdered mineral pigments which we mixed with limewater and painted onto the leather hard plaster.
The section under the bench had been kinda ugly until now.. This is lime plaster, first with blue pigment and followed with black lettering.