On mud floors
Down and Dirty - New York Times

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.