Homeowners thinking outside the traditional wood-framed residential box are pouring on the creativity when building houses with precast concrete walls.
Not only used in below-grade applications, concrete shows its durability and energy efficiency from the ground up in new home construction, says James Baty, executive director of the Concrete Foundations Association, based in Mount Vernon, Iowa.
“It’s hard to beat concrete’s thermal performance, storm resistance and sustainability qualities,” he said. “A concrete home built with the proper supports can easily last 200 years and, as in ‘The Three Pigs’ fairy tale, can withstand nature’s ‘huffs and puffs’ better than the house made of sticks.”
Concrete is comprised of cement, which is a fine powder made from limestone, clay and/or shale. When mixed with water, cement binds aggregates, such as sand and gravel, into solid concrete through a chemical reaction called hydration.
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But Baty says today’s concrete isn’t that of your grandfather’s generation. Technological advances build a better, stronger and firmer concrete, especially when it comes to the precast variety.
Superior Walls of America, based in New Holland, Pa., is a 35-year-old company with a dozen licensees in the United States and Canada. It has been an innovator in precast concrete building systems since its inception, says company president Jim Costello.
The precast concrete process is one in which wall panels are fabricated to architectural plans in factory-controlled conditions and assembled on site, Costello says.
“Instead of pouring concrete into forms on the construction site, our products are steel-reinforced concrete walls with insulation inside, for the highest energy efficiency,” he said. “Precast concrete walls are up to 10 1/4 inches thick and can be up to 12 feet tall with custom-made holes so forms are easily bolted together to create a tight seal.”
A specially formulated concrete that can withstand up to 5,000 pounds per square inch after a full 28-day curing process, precast concrete wall panels need not remain a utilitarian gray color. Texture can also be achieved in precast concrete walls shortly after being poured into forms through stamping — a process by which patterns are pressed into wet concrete. Colorants can be spread over the top of stamped, wet concrete so the outside of panels can emulate stones or bricks. Or after the house is built, masonry workers can affix stone or brickwork to concrete panels.
Foam insulation is layered in each precast form and acts as an impervious barrier to water and air. Precast concrete forms serve as a solid wall structure, and are bolted together for below-grade applications and multiple-story homes. When fit together according to architectural plans, the precast concrete walls create a tight building envelope, which wins awards for energy efficiency.
“There’s a higher concentration of concrete homes in Europe, while concrete homes in North America can range from 15 percent to 25 percent more on front-end costs than traditional new construction that uses wood,” Baty said. “But we are finding that more people are considering building concrete homes in storm-prone coastal regions and in places where tornadoes are prevalent.”
An energy-efficient home in Litchfield, Conn., constructed with Superior Walls precast concrete wall panels, was recently declared a winner in the state’s sixth annual Zero Energy Challenge. The residence, built by Revival Homes LLC of New Hartford, tied in the category for the home with the “lowest projected annual net operating cost.”
The precast concrete walls are structural but also serve as the finished surface on the outside of the home. Since the low-maintenance concrete panels will not burn or rot over time, they add to the durability and energy efficiency of the home.
Precast concrete panels have vertical steel rebar inside each stud and insulated access holes for ease in wiring and plumbing. Inside the home, galvanized steel stud facings are ready for drywall or plasterboard finishing, so interior walls conceal the solid stone-cold nature of concrete.
Meticulous planning is essential when choosing to build a concrete home made of precast walls, because once poured, walls are set in concrete.
“The beauty of concrete is that it can be formed in all different shapes,” Costello said. “A house in the round, or geodome, made of concrete is attainable if an architect can plan it, then we can cast it and build it.”