Habitat pioneers new kind of home

SILER CITY -- Volunteer home builders with Chatham Habitat for Humanity showed up in the Westmont subdivision with their tool belts and hammers for a Saturday of wall raising. But they stood by while another volunteer did the heavy lifting on this unusual home construction project.

A crane loaned by Davis Rigging & Welding hoisted precast concrete walls weighing 7,000 to 13,000 pounds off a flatbed trailer and lowered them into place. Five hours later, a clay-stained concrete slab was transformed into a structure with walls that resembled gray stucco.

Precast concrete panels, long used in commercial construction, are a relatively new material for residential building. The Chatham affiliate of Habitat for Humanity, a Christian-based international organization that aims to eliminate substandard housing, is pioneering the use of the panels for the first precast Habitat house built in the Triangle area.

"We're always interested in trying new things that make sense with regard to construction of Habitat houses," said Amy Powell, executive director of Chatham Habitat for Humanity. "We use volunteers to a great extent to build houses. This will save us about eight weeks of volunteer labor."

Powell said the group hoped to have the house finished and ready for a family by June, months sooner than it would otherwise be ready. The Habitat board will weigh the savings in volunteer time, durability and energy efficiency against the higher cost of the building material.

Greg Lask, vice president of International Precast Inc., a Siler City company, serves on the local Habitat group's construction committee and approached the board about trying out the material as a way to put up houses more quickly.

"It started with an idea about a year ago to try to make a difference," said Lask, as he watched his crew secure the walls.

"We can only build about 12 homes a year for people who need them," he said. "My thinking was we need to be building 50 homes a year, not 15. How could we do it faster?"

The walls were manufactured offsite by Lask's company, then trucked to the home site. International Precast donated the panels and labor, which represent a savings to Habitat of about $4,000 in building materials.

The quicker construction comes at a price. Lask said a wood frame house costs about $9 per square foot to build, while a house made with precast panels runs about $12 per square foot. But he said the homeowner enjoys lasting savings in energy costs. In addition, the durable building materials resist moisture, termites and other pests.

The 8-inch-thick walls consist of 2 inches of foam insulation sandwiched between 3-inch-thick sides of concrete. Because the insulated concrete panels retain heat and are more energy efficient, homeowners can install smaller heating and cooling systems and save on power bills.

"We're trying to build a better future." Lask said. "We're trying to build cost-effective housing that is energy efficient."

Ellen Cassilly, a Durham architect who teaches sustainable design seminars at N.C. State University's College of Design, said precast concrete is sturdy, which makes it well suited to high winds on the coast. She said it also has excellent insulating properties, and its appearance may be attractive to people who like the rougher look of stucco.

Despite its attributes, however, the material is not particularly common in residential construction, Cassilly said. Her firm has used precast concrete panels in a small weekend house it designed in Person County.

"I think it's great that Habitat is trying it," Cassilly said. "It has great promise."