Cob is an ancient building material, consisting of clay soil, course sand and straw. Combined with water, this material is used to build thick load bearing walls. Cob has been used on all continents, dating back to ancient Egypt, China, India and England. In souther England alone, in the counties of Devon and Cornwall, it is estimated that there are approximately 40,000 cob buildings, ranging in age from 250 to 800 years old. Cob was one of the principal building techniques of England for hundreds of years, until the invention of fired brick and the advent of the railroad, which delivered bricks to the masses. In the southwestern United States and down into Central and South America, Cob’s sister technique is called adobe, and was the principal building technique in some of those regions for hundreds of years. Adobe is formed into blocks first, and then stacked, whereas with cob, the material is built wet on the wall in lifts of 18 to 24 inches and is therefore considered monolithic. Cob is a sculptural material, allowing for the creation of tapered curvilinear walls, which are significantly stronger than straight walls.
The current interest in cob construction started in the late 1980’s when Ianto Evans and Linda Smiley took a trip to Wales and Scotland, researching old earthen buildings. They returned to the states and with Michael Smith, started the Cob Cottage Co., which began teaching cob building workshops around the U.S., igniting an interest in this ancient earth building technique.
I started working with cob in 1999, after reading Michael Smiths “ Cobbers Companion”, and moving to an area rich in good red clay. I built a small wall in my carport, and then helped a local friend build her cob house over the next couple years, hosting workshops with the Cob Cottage Co. in cob construction, poured adobe floors and earthen plasters. I also apprenticed with The Cob Cottage Co. in 2000 and 2001, taking their first apprenticeship program in Coquille, OR.
I returned from my apprenticeship to my home in Nevada County and began a Cob building career in my local community. I’ve been building professionally ever since for local clients and teaching week long cob workshops and multi week start to finish cob workshops, where students come and have a hands on learning experience building with cob.
I started out building garden courtyard walls with earthen roofs and cedar shake roofs, playing with curvilinear shapes, intimate spaces and built in seating areas where people could gather together outside. I incorporated large rock foundations, bas-relief sculptural details, arched walkways and openings, altar niches and round pole timber framing.
I continued exploring with cob, building a number of small round sauna buildings, with curved ridge beams, round pole rafters and earthen roofs. With a large wood stove in the sauna, and a welded metal box on top of the stove for rocks, these wet saunas were my first taste of sitting in a sacred space and holding sacred intention. I went on to build a few more of these over the years, hosting small gatherings where groups would “sweat”, pray, chant, share and plunge in cold water in large animal feeding troughs outside the sauna. I became really interested in these buildings as a container, both literal and energetic, for holding sacred space with groups. I found the small, intimate setting, sitting cross legged on the floor, to be an ideal setting for people to do sacred work in. The buildings felt more like a womb space, with soft curving walls and sacred altars, lit by candle light and the glow of a fire.
After 16 years of building with cob, I’m still fascinated by these little buildings and what they have to offer us. As I prepare this next years building schedule, it seems that 2 or 3 more may get built this year!
After building saunas and garden walls, I naturally moved on to building houses, spending many months building an 1100 sq. ft. home for a local couple with an English bloke by the name of Simon Holmes. This experience lead me to design, and eventually build my own home out of cob, for me and my family.
This home was a very ambitious project. With a 2000 sq. ft. footprint and a large upstairs, the house came in at 3000 sq.ft., with load bearing cob on the north side, a post and beam frame on the south side, mixed with windows, glass doors, and an integrated green house, for a passive solar design.
The center ridge line was composed of a very large round pole, post and beam timber frame, consisting of 6 large posts and two ridge beams, totaling 75 feet in length. The gable ends were strawbale construction, up to the ridge beam. The downstairs consists of a vaulted ceiling living room, dining room and kitchen with attached pantry, master bedroom with its own entrance and walk-in closet, meditation room, 2 offices, a bathroom and laundry room with its own entrance. The upstairs consists of 2 bedrooms, a guest room, an art room and a bathroom, looking over the downstairs great room. The house is finished out in earthen plasters, inside and out, and a 2000 sq. ft radiantly heated poured adobe floor. It has 3 covered porches, 2 of them with earthen roofs, and 11 cob benches throughout the house. It took me almost 3 years to build it, with a crew ranging in size from 12, during the cob, to 6 for the finishing. As far as I know, it is the biggest cob house on the west coast.
Since finishing the house , I’ve been focusing on building smaller spaces, moving back towards my love of saunas, round sacred spaces, retreat cabins, bath houses and teaching workshops. I continue to build with cob, and other natural materials, full time, year round, and am now entering my 17th building season on the San Juan Ridge, near Nevada City, Ca. I hope you enjoy this site, these photos of my cob journey, and become inspired to try building with cob or take one of my workshops.
Rob Pollacek / Sequoia Sun