The latest thing in chic houses - floors of mud

Down and Dirty -- by DAVID GELLES/NY Times

EL CERRITO, Calif.

EARLY one Saturday morning in January, Kevin Rowell dumped a bucket of dark mud on the floor of his big south-facing bedroom. It landed with a plop, spreading out and merging with a blanket of wet earth that already extended across much of the room. On his knees, Mr. Rowell took a trowel to the pile, nudging it this way and that until the mud was roughly level and about an inch and a half deep.

As Mr. Rowell finished smoothing that section, his wife, Marisha Farnsworth, appeared at the door and handed him another bucket of mud. A moment later, another plop, and the process continued. The mud was expanding, and would soon cover the entire floor .

“It’s beautiful,” said Mr. Rowell, 28, as he stood back to take in the whole room. “It’s just what we wanted.”

Mr. Rowell and Ms. Farnsworth, 26, were working with a dozen friends to install a dirt floor — an “earthen floor,” as it is known — in their newly purchased 50-year-old home in this Oakland suburb.

The floor — which, in addition to the basic ingredient, included lime and sand, two classic components of concrete — would take a few weeks to dry, a period when the couple would camp out in their living room. But once sealed with a mixture of linseed oil and beeswax, it would theoretically be firm and water-repellent. Fans of such floors say that soapy water will clean them without turning them to mud, and that another coat of oil can renew the shine.

The couple are part of a new breed of environmentally conscious homeowners who are willing to forgo traditional floorings like hardwood, carpeting and concrete for the supposed benefits of earthen floors: a reduction in heating costs and environmental impact and, at least in the eyes of some, an improvement in looks.

They are part of a small movement interested in “natural building” on the fringes of green architecture. But they consider green architecture to be overly focused on energy efficiency, while they are concerned with the eco-friendliness of the entire process. The idea, according to Lloyd Kahn, a former shelter editor of the Whole Earth Catalog, is to use “materials that have as little processing as possible, like dirt, straw and bamboo.”

It is hardly a new or chic movement: millions of poor people around the globe use natural materials like dirt for their homes whether they want to or not. But with the growing environmental awareness in this country, Mr. Kahn said, there is greater interest in natural building materials like dirt.

Aesthetically, earthen floors are “really special,” said Frank Meyer, a natural builder who has installed 15 in Austin, Tex. “After a while they look like an old cracked leather couch,” he said. “When people walk in, they don’t say, ‘Oh, nice floor.’ Everyone gets down on their hands and knees to admire it.” Mr. Meyer has used natural pigment to create designs in some floors, and he said some builders add the blood of oxen for maroon coloration.

Some aficionados see a spiritual aspect to earthen floors, too. Mr. Rowell said his floor would help create a “sacred space.” Mr. Meyer agreed. “I think people are craving the earth,” he said. “They want to be more primal. How much more primal can you get than dirt?”

Michael G. Smith, a natural builder who teaches workshops on installing earthen floors at the Emerald Earth Sanctuary in Boonville, Calif., said that demand for dirt floors is growing quickly. Of course, they are still extremely rare. He estimated that a few hundred, or perhaps a few thousand, have been installed around the country.

He has installed a dozen himself for clients over several years, and said that the number of earthen building workshops like his have increased. Ten years ago, there were at most four people offering them in California, he said, and “now there are 20-plus.”

Jack Stephens, the executive director of the Natural Building Network, which was founded in 2005, said that its database now includes several thousand builders.

In Portland, Ore., Sukita Crimmel is focusing her natural building firm, From These Hands, on the design and construction of earthen floors. After installing just one or two each year over a seven-year period, she already has contracts to do at least four in 2007. And in Crestone, Colo., Erin and Talmath Lakai, who run a natural building company called MudCrafters, say they have gone from installing four or five floors a year to a planned 12 in 2007. “We’re fully booked,” Ms. Lakai said, “and we’re booking two years out from now.”

But lest anyone get the wrong impression, dirt is neither easy nor trouble-free — nor is it entirely practical, as women who wear pointy four-inch heels will find.

In a lot of places, the dirt often “cracks horrendously,” said Bill Steen, a natural builder in Elgin, Ariz., because “they just pound it into place.” Mr. Steen and his wife, Athena Swentzell Steen, have led an effort to modernize the techniques, adding sand and fiber in carefully calibrated amounts to control cracking.

Mr. Steen, 59, is half Mexican and grew up in an adobe house in Tucson with earthen patios. Ms. Swentzell Steen, 45, who is half Pueblo Indian, grew up in adobe houses in Santa Fe., N.M. “When you grow up and you’re living in a house that’s got three-foot adobe walls, that stuff just imprints on you.” Mr. Steen said.

“We kept thinking about the materials, the clay,” he added. “We decided to refine that recipe and make a floor that was crack-free, solid and really serviceable.” (Mr. Steen’s instructional pamphlet, “Earthen Floors,” is something of a bible to natural builders; it is out of print, but he said an updated version would be available on the couple’s Web site, caneloproject.com , within a few months.)

“There’s all sorts of recipes” for the floors, Mr. Steen said. “There’s no one way to do it.”

In fact, no firm standards seem to exist. Michelle Moore, a vice president of the United States Green Building Council, a nonprofit industry group in Washington that sets standards for pro-environment construction, said that its guidelines don’t even mention earthen floors or natural building. She said, however: “We envision a future where all buildings are green. Natural building techniques are an important part of that, but they’re not the only approach.”

And Steven Moore, director of the graduate program in sustainable design in the architecture school of the University of Texas at Austin, said that such building techniques “are not part of the program at all.”

For natural builders, the most practical benefit of earthen floors is thermal. (The high density and low thermal conductivity of an earthen floor allows it to capture and retain warmth.) Some builders install radiant heating systems in their floors, which circulate hot water and reduce the need for conventional heating. And when the floor receives direct sunlight it can act as a passive solar device, absorbing heat during the day and releasing it at night.

At the moment, the floors are more popular in the West than elsewhere. “The East Coast tends to be much more conservative,” said Mary Golden, a builder in Rochester who has contracts to install two earthen floors this summer and already has one in her own home. “And it’s inertia. They came out of the Southwest, and they’re taking their time moving across the country.”

Earthen floors are not right for every room in the house, Mr. Meyer said. “It’s great for a sitting room, a library or a hearth around the fireplace, but I don’t recommend them for wet areas like bathrooms or kitchens,” he said. “They are vulnerable. If you ever have a flood in your house, it’s going to saturate it and you’re going to have a big mess.”

Tressa and Esteban Hollander had such a mess when they forgot to turn off the irrigation system in their earthen-floored garden room in 2005 in Crestone, Colo. Six hundred gallons of water seeped into the floor in two hours, soaking not only that room but the hallway, the dining room and a bedroom. The surface blackened and blistered, destroying the finish, and the entire floor had to be torn up. It took a month to reinstall.

Still, “it would have been a problem no matter what kind of floor we had,” Ms. Hollander said. “It was actually easier to take up the earth floor than a cement or hardwood floor. You just dig it up.” After the cleanup, the couple installed another dirt floor.

And although earthen floors are durable when well installed, “there are things they don’t tolerate well, such as point loads,” Mr. Steen said. “Twenty women in high-heeled shoes would not be good.”

Even chair legs can be problematic. When Jenny and Chris Altenbach moved into their earthen-floored straw-bale house in Albuquerque in 2006 they left tiny craters in the floor whenever they sat down in a chair. “It hadn’t developed the proper hardness, and we got a lot of dents and scratches,” Ms. Altenbach said.

The floors were subjected to other punishing tests. Ms. Altenbach said their dogs were not house-trained and occasionally left stains, and their daughter, Eliza, enjoyed drawing on the dirt floor with markers.

But like most true believers, the couple were not easily discouraged. “The imperfections just add to the character of the floors,” Ms. Altenbach said. “We’ve had every kind of mess you can imagine. Some of the stains show, but it only makes these floors more beautiful, like an aging leather jacket.”

Unlike point loads, fifty people in socks don’t seem to be a problem. Laurie and Anibal Guevara-Stone had a large housewarming party in 2006 as soon as the floors were sealed in their “no shoes allowed” house near Aspen, Colo. “We spilled beer and wine on it, and it was fine,” Ms. Guevara-Stone said. “The linseed oil and wax sealant didn’t allow any of the liquids into the floor. Even the wine didn’t stain.”

Mr. Rowell and Ms. Farnsworth said that one of the most appealing aspects of the new earthen floor in their bedroom was its cost. “Our material cost per square foot is about a dollar, if that,” Mr. Rowell said. Labor costs included, earthen floors can run as little as $5 a square foot, compared with $15 or more for hardwood. But because so much of the work on their floor was done voluntarily by friends, the cost was even lower.

They used French lime as a hardener in their mix, an ingredient that Mr. Steen said he generally avoids because “it can weaken the floors.” Their recipe also calls for using paper pulp as fiber to reduce expansion and prevent cracking in the floor (some builders use straw), which required their crew to spend two hours on the morning of the installation turning paper to pulp with a high-pressure hose. Other crew members sifted the clumpy gray clay to remove any rocks. Then the clay and pulp were fed into a growling stucco mixer in the driveway, and combined with store-bought sand and the lime.

A bucket brigade then hauled the mud into the bedroom, and one plop at a time the couple’s earthen floor took shape over a dried layer of dirt and straw that the couple had already installed over a one-inch foam core. (Mr. Rowell acknowledged that the use of nonbiodegradable foam rather than the traditional layers of packed earth and gravel was a compromise, in natural-building terms.)

After a day of constant churning, the stucco mixer in the driveway broke down, and Ms. Farnsworth blended the final batch in a paint bucket with a small paddle mixer. Only after eight hours was the crew, exhausted and mud-spattered, finished.

At nightfall the floor remained a storm-cloud gray, drying slowly in the cool humidity. A six-inch crack already snaked out from the wall, but Mr. Rowell was unfazed. “It’s an organic thing,” he said.