Due to prison overcrowding the Gila unit was built with portable modular housing.

"And instead of that," he added, "they're just going to be putting in vinyl-sided modular housing."

What do traditional builders think about modular housing?

But while modular housing is promoted as a way to trim 10 to 20 percent from construction costs, that is not always true.

In New York City, modular housing has a legacy of disappointments.

"When you talk about the hard costs involved in building a house," he said, "there are distinct cost advantages that favor modular housing."

The construction of modular housing is regulated by a combination of state and local requirements.

Unlike modular housing, panelized housing is not being touted as inexpensive.

Some are regulatory; building inspectors are often unfamiliar with modular housing, and customers must buy through a developer rather than from manufacturers.

In 2005, Champion was the first manufacturer to build privatized modular housing for the military.