A Weekend Building with Cob at the Mud Dauber School

In the calm of an early Saturday morning last May, I drove northeast from Charlotte North Carolina, ready for my first experience with cob and natural building. Passing through Asheboro, I turned off the highways and onto the empty roads of the unincorporated county of Snow Camp—located in between Durham and Greensboro, just west of Saxapahaw and the Haw River. The switch away from the city feeling was almost immediate. I knew I was in the country when I saw cows joyfully grazing on a hillside, a man in overalls riding a tractor, a taxidermy place, and open fields filled with hay bails.

On the front of an unassuming ramshackle shed with dark faded wood, was a prominent white sign with the logo for the Mud Dauber School. I pulled into the dirt road, and parked beside two other cars close to the entrance. It was quiet and the late spring air was clean and filled with the smells of the forest.

A few steps down the road and I found several small cob buildings set amongst the trees, and a central building where a few people were congregating for breakfast. Some had stayed the night before and were still waking with a cup of coffee.

Greg addressing the group in front of the central cob building for meeting and eating, with its living roof. Washing bins for dishes are also visible on the right.

It was fascinating to hear about how everyone had become interested in natural building. There was a common thread between at least three of us with a background (or career) in the arts. That makes sense with the act of creating, shaping and working with your hands. One woman was an art teacher who had traveled much farther than me, and was planning to build a cob greenhouse. Another was involved in pottery. Another guy had become interested a long time ago, and was getting back into it.

A Tour Around the Property

After breakfast and introductions, Greg, the teacher of the class, gave us a tour around the property (~10 acres). He had built a lovely 2-story house for his family, with a mix of wood, strawbale, and cob construction.

On the property was a small pond and at least 5 cob buildings of different shapes and sizes. A few small ones used as guest houses were square. The round one is pictured at the start of this article. And there was a medium-sized building with a pitched roof and a loft.

Cob houses can be square with pitched roofs too. This one has a sleeping loft, its own porch, and a small side room.
I love this little garden table on the side of the building made with roundwood from the property.
This terrible photo does not do this room justice. The soft and diffused look of light on cob wall with natural plaster is very pleasing to the eye. This cob house even had a mini-fridge.

Stomping and Rolling a “Burrito”

After having a look around, we got to work.

First, we filled some wheelbarrows with sand from a pile near the road, and pushed them over near the clay. We then broke up the clay and filled buckets with it. Lots of buckets. Then Greg and Matt gave us a demonstration.

A pile of clay that we moved into buckets for each batch of cob. Mixing on a tarp in the background. The white building on the right is the one I later stayed the night in.

One of the beauties of cob is how simple it is to create. Its mix of clay, sand, straw, and water only requires your body and a tarp to put together.

After a tarp is spread on the ground, we dumped the clay and sand on top. Getting the right ratio of clay to sand is not an exact science, because of the different makeup of the materials. Then we poured some water on top from a bucket. You don’t want to use too much water. The final cob will be a little wet, but not soupy.

Then comes the fun part of stomping, or dancing, in it with your bare feet, to mix everything evenly. It feels a little funny at first, not being used to stepping barefoot in wet soil. You get used to it. What the tarp does is allow you to grab one side, and pull it over to turn the drier sand and clay on top, so you can continue using your feet, particularly your heels. As you keep repeating this, eventually the mixture of clay and sand will start to “burrito”, meaning that it will start to hold a single folded-over shape, rather than completely falling apart.

Mixing clay, sand, and straw on tarps.

Around this time, you scatter a few handfuls of straw (note: which is totally different from hay, as some of us jokingly discussed when referring to it by the wrong word) on top. And then continuing the mixing. The straw helps to add tensile strength to the cob. It was surprising to me how much this does to strengthen the material and prevent it from pulling apart.

I think that cob has a lot of potential in the Piedmont of North Carolina, with clay being such an abundant resource. There is free building material right under our feet. The clay we used at this workshop was dug up right on the property. The pile of sand and the straw was brought in from off-site, but sourced locally.

Building a Rounded Bench

Newly formed bench made of cob

We moved the cob into this in-progress outdoor room, connected to the dining area. With our hands we scooped and molded the cob onto the top and back of the rounded stone bench. This forms the structure that will later be finished and smoothed out, likely with a natural earthen plaster.

Frog Sounds and Sleeping in a Tiny Cob House

That evening we had a healthy and delicious meal, relaxed with some beers, and were able to use the hot shower at the bathhouse before turning in.

I stayed the night in one of the tiny cob cabins. With a window on one side and the door centered on the other, it was as wide as the bed. There was a small nightstand with a lamp (basic electric was run through some extension cords), and that’s about it.

After a full day of physical exertion, I was worn out and ready to sleep like a rock. This was fortunate because the top of the door on this cabin was a screen, open to the full sounds of nature. The frogs in the pond were unceasing with their high-pitched croaks. It took a little time to get used to the sound and this environment, but it was comfy and I slept soundly.

Day 2: Clay Slip, Natural Plaster, and More

The second day activities were varied.

We learned how to make and apply earthen plaster. Starting by gathering and filtering out clay slip from large plastic barrels, we churned this with sand in a wheelbarrow in a particular way with a shovel. Having someone else help by slowing pouring in the sand while it was being mixed, made it less exhausting.

Using trowels, we applied this to the unfinished back wall of the dining area building, eventually covering the whole thing. There is an art to it that you need to figure out by doing—not dropping the plaster on the ground, how to work around the edges and tops/bottoms, how much to apply and keep it smooth and consistent, etc. And there were different types of trowels, of varying sizes, shape (square edge or round edge) and quality.

After that we also filled a small wire mesh wall with straw bonded with clay slip. Greg gave us a presentation about some structural techniques using a whiteboard, and answered our many questions. He also showed us a slideshow of some other projects, talking through many of the details of the construction.

Homemade Pizza

Before we left, we had a glorious final meal; pizzas handmade with fresh ingredients and cooked in the outdoor cob oven. I could have made and ate those pizzas all day. I decided that I must build a cob oven once I have a place to do it.

Greg gave us a tour of his house too. The interior was filled with so many interesting shapes and spaces around every corner. Especially the upstairs.

Takeaways

This weekend workshop was 100% worth taking. Greg, Matt, and everyone there was incredibly knowledgeable, friendly, and accommodating. If you’re thinking about it, just do it. I left energized with new skills and the feeling that “Hey, I could build this!”. I’d like to get more experience with the roofing, windows, and foundation, but I have enough familiarity with the techniques now to carry me forward. There is a full week class that covers more of those techniques.

The Mud Dauber School still has some workshops for this year in June, July, and September.

One suggestion if you go; bring a notebook, pen, and some sandals. My phone ended up running out of battery, and taking notes on it was not ideal. If I go back again, I will take more photos now that I have a real camera.

It was also a relaxing getaway and an enjoyable time spent outdoors. I can’t wait until the day that I can use what I’ve learned to build my own cob cottage, oven, and/or garden wall.

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