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Round House Curve Appeal
In the small town of Nebaj, about six hours north of Guatemala City in Guatemala, Elba Méndez and her family have preserved the country’s vernacular architecture form by building a round home from a mixture of cob and cordwood. “We wanted to build an earthen home because they’re so much nicer than the block and cement homes everyone is building around town,” she says. “We also wanted to make a round home because no one else in town has a circular house.”
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Circular homes don't have corners that end up gathering dust. Generally speaking, round homes allow for more efficient use of space, and creative interior design with natural flow between spaces. As an added benefit, round homes are generally less expensive to build. The lack of complicated structures and multiple surfaces can require up to 20 percent fewer materials per square foot of construction, thus driving down the final cost.
3. Energy Efficiency of a Round House
Round homes are more energy efficient than their rectangular counterparts. Why? Because they have less surface area relative to floor space, there is less wall exposure to the exterior elements. This allows homeowners to invest in high-efficiency insulation and high performance windows in strategic wall spaces to maximize the energy efficiency and thermal performance of the home.
Because round homes are naturally aerodynamic, they’re less drafty, thus further increasing the homes’ comfort and thermal performance. In addition, round homes use fewer materials. In geometric terms, the circle has the shortest boundary relative to its area, thus requiring less material for overall home construction—which gives round homes a lower embodied energy rating than other homes.
North America: Net-Zero Model Round Home
The Deltec Innovation Center, a 1,500-square-foot Net-Zero Model Home in Mars Hill, North Carolina, is one example of a sustainable round home. The model home has reduced the exterior surface area for the same interior square footage, resulting in less total heat loss and lower heating and cooling demand.
The dirt and straw are mixed with water, then placed on top of a rock stem wall that protects the wall from moisture at ground level. Because the mixture is not first made into bricks (like traditional adobe), there are no mortar joints, essentially making the cob wall one solid structure, similar to poured cement.
Initially, Mendez was worried about the work required to mix the cob for her new round house, she says, “so we were able to get 150 pieces of cedar cordwood that we incorporated into the walls of the home. This reduced the amount of cob we had to mix. It also offered a unique final look to the home once we finished the natural plasters and varnished the pieces of wood.”
The cob/cordwood round house incorporates up-cycled materials. “The post and beam structure for the roof was sourced from a wood house that was being torn down for a more modern cement home,” Méndez says. “I also found broken glass that we used for making small, circular windows to maximize the amount of natural light. Around the wood-framed windows, we added blue and green wine bottles that flood the home with unique light during the early morning.”
Living in a Round House
Our ancestors might have understood one quality of a round home that’s a little less obvious than reduced energy use and clever space allocation: the powerful and natural movement of air and sound. As David Raitt, a yurt builder has said: “Circular living provides a balance of looking inward and outward, looking out at the natural environment and surroundings but then coming in again to the self and the hearth.” The curve appeal of round homes today comes in the form of a house of the future, based on the past.
Tobias Roberts
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.
