It began as an effort to provide affordable housing to people left homeless by Hurricane Katrina. But it has grown to become an alternative for Americans looking for in-law housing or vacation homes.

It’s the Katrina Cottage, a small house that is sturdy, expandable and can be built in a matter of weeks.

The first of these bare-bones homes was designed by New York architect Marianne Cusato. Last year, she partnered with home improvement retailer Lowe’s to sell designs for the cottages at the home improvement retailer’s U.S. Gulf stores.

In late June, Lowe’s made the home plans available in all its stores.

“They have been selling in the Gulf, but we’re really finding the greater interest is around the country,” Lowe’s spokeswoman Chris Ahearn said.

She declined to give sales figures but added that “a lot of people are looking at them as vacation homes, lake or mountain cottages.”

Lowe’s sells floor plans and building materials for 11 models designed by Cusato and other architects. The homes start at 544 square feet, and feature a living room, bedroom, kitchen and porch. They have metal roofs, and siding that is rot- and termite-resistant.

Initial costs for the design and materials range from $45 to $55 a square foot. Buyers will need to hire a contractor, adding to the cost, and have their own land on which to build.