Mud Floor or Antique Lavar?

Early one Saturday morning, Kevin Rowell dumped a bucket of dark mud on the floor of his bedroom. It landed with a plop, spreading out and merging with a blanket of wet earth that would eventually 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."

The floor would take a few weeks to dry, a period when the couple would camp out in their living room.

Aesthetically, earthen floors are "really special," said Frank Meyer, a natural builder. "After a while they look like an old, cracked leather couch." Everyone gets down on their hands and knees to admire it." Mr. Meyer 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."

But lest anyone get the wrong impression, dirt is neither easy nor trouble-free -- nor is it entirely practical. 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 irrigated system in their earthen-floored garden room and 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.

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."