Striking, yet functional: hurricanes were a major concern for the home's owner, architect, and concrete producer

Concrete Producer, The, July, 2005 by Faye Goolrick

David Howard enjoys making other people's dreams come true. So when someone was looking for an innovative home that would be attractive yet functional, Howard came to the rescue and provided his favorite building product--concrete.

As the founder and president of Concrete Express Inc. (CONEX), a Georgia ready-mixed concrete producer with three locations, Howard had long dreamed of providing concrete for such a house. The future homeowner's dream would become reality when Howard met William H. (Bill) Harrison, an architect and longtime concrete enthusiast selected by the Portland Cement Association to design its 2001 concrete show house, "Safe Haven," a French Provincial-style mansion featured during the International Builders' Show in Atlanta.

In mid-2004, the Harrison and Howard teams began planning the house, to be built on a secluded site along a tidal creek near the Intracoastal Waterway between Savannah and Wilmington Island, Ga. The owner had three goals for his dream home.

First, he wanted a popular, appealing contemporary look offering lots of open space and big windows for viewing the expanse of marshland and tidal creeks surrounding the property.

Second, the owner wanted a structure strong enough to survive occasional high tide flooding as well as every coastal resident's nightmare, the rare but inescapable 100-mph hurricane. (Four hurricanes hit Georgia in 2004.) Howard wanted to demonstrate that the beauty of a good plan and the safety concrete provides were affordable. He used self-consolidating concrete (SCC) and insulating concrete forms (ICFs).

Finally, the homeowner had concerns about the price tag. Howard responded by holding down costs by adapting standard commercial concrete building materials such as masonry block and extruded, pre-stressed decking wherever possible.

The result is a striking two-story residence with 5600 square feet of heated living space, in addition to 7400 square feet of ground-floor garage, covered porches, and storage space.

Designed for a recreational beach and boating lifestyle, the house has guest bedrooms downstairs and a master bedroom suite and an office upstairs; a main-level screened porch with a concrete fireplace and an outdoor kitchen (with a countertop pass-through to a spacious indoor kitchen); a turret-shaped, windowed dining room with a custom cast-in-place concrete-base mahogany table; a living room that opens onto a spiral-shaped, three-tiered swimming pool and spa; and river access via a floating concrete dock.

Devoted to concrete

For Howard, whose company is supplying 1500 yards of concrete for the house, the job offers an ideal opportunity to apply the latest advances in concrete technology to residential construction.

A civil engineer by training, Howard started his own ready-mixed concrete company in 1995, continuing a legacy dating back to when his father worked for a small producer 40 years ago. Concrete's properties and its various mixes interests him so much, that he occasionally teaches courses in concrete technology at nearby Georgia Southern University, his alma mater.

Howard was particularly interested in ICFs and SCC. But he soon learned that the techniques require more precision and attention to detail than some experienced subcontractors and site managers were willing to provide. "Masons don't want to know anything except brick and block, and the carpentry trades are just not real interested in concrete," he says. After reconfiguring his work crews and terminating his first site manager, he began supervising the job directly himself.

"This was my first experience with ICFs, and I soon learned that bracing and shoring are critical in dealing with light non-structural formwork," he says. "You cannot skimp." To provide additional assistance, the ICF manufacturer, Reward Wall Systems, had a representative onsite periodically.

All of the second- and third-floor exterior walls are made entirely of ICFs. To create window openings, window bucks were secured by tie wire and rebar, with observation holes drilled in the bottom of the sills to allow workers to see when the concrete reached the right level, thus assuring that the forms were completely filled.

SCC was used for the house's ground-level (garage) walls, but was poured in place using steel forms, not ICFs. Still, the SCC with Sika's Sikament admixture allowed the 10-foot-high, 10-inch-thick walls to be poured at one time with only minimal movement of the pump.

The garage floor is set 2 feet above grade and constructed on a base of flowable fill--a combination of sand, fly ash, cement, and water--that guarantees full 2000-psf compaction around the foundation. (Flowable fill is fully excavatable and safer for trenching in areas with a high water table.)

Building by example

Walking around the site on a breezy spring afternoon, Howard surveys the water conditions, then gestures across a small inlet to the house next door. "This property was once a 450-acre plantation, and the last major, head-on hurricane to hit here was in 1880," he explains. "That house was built in 1885. The story is that the builders used heart pine remnants from earlier houses destroyed by the storm."