This estate-class home, built by the Carrell Group, is one of the most remarkable ICF homes in North America. Finished in September of 2016, the massive 30,000-sq.-ft.-plus residence was built over a period of five years in a small seaside community on the state line separating the Carolinas.
The project has the scale of a commercial build. Three stories of ICF sit atop 14-foot basement walls. With each of the other stories at 12 feet each, ICF workers were stacking and pouring the upper walls 50 feet or more above the ground. In open areas, such as the living room, walls stretch 30 feet without intermediate floors, and in some areas are much taller. A large number of jogs and unusual angles also complicated the build. In total, the house has just less than 29,000 sq. ft. of conditioned space, with an additional 3,400 sq. ft. of decks and covered porches.
Construction began in the depths of the recession, and Grant DuBose, vice president of Carrell Group reports that managing invoicing and cash flow proved challenging. "We operate in a relatively small town, and some of the subcontractor and vendor contracts were over $500,000 individually, so companies had to be carefully vetted to ensure they could endure the technical and financial burdens of such a large project," he says. "We constantly stayed in communication with our vendors and others in their supply chains just to ensure that everyone was being paid and we wouldn’t see any future liens on the property."
From the beginning, quality was the overarching consideration. DuBose says, "The homeowner hired an independent special engineer to inspect all rebar placement, concrete pours, and independent lab testing of the compressive strength of concrete throughout the project. In other words, the ICF contractor had to be accurate because he was being inspected regularly by an outside engineer."
There were other incentives to be accurate. For instance, the window and door package exceeded a half million dollars, and the order was placed well in advance of the walls being built. Fortunately, the ICF installer's attention to detail during the placing, bracing, and pouring around the V-Buck ensured that the openings were square, level, plumb, and precisely the right size.
The home—including windows and roof—is designed be hurricane proof. Even the floor-to-ceiling glass windows can withstand 160 mph winds. The basement walls were cast with removable forms for termite protection. All interior walls and roof trusses are light-gauge steel stud. The floors and deck were formed with Insul-Deck, an ICF flooring system, to ensure durability and strength. The weight of all this concrete was far too heavy for the sandy coastal soil, so the home sits atop 129 16-inch-diameter piers, each driven forty feet into the ground and capped by a large and continuous concrete grade beam.
The flooring is genuine Italian marble, shipped by boat, including a custom 15-foot diameter floor medallion, laid piece by piece in the rotunda where it can be viewed from the mezzanine. To keep heating and cooling costs manageable, the house and pool utilize a geothermal heating and cooling system, tied to 50 geothermal wells, each 300 ft. deep.
DuBose says, "There is no home like this, ICF or otherwise, anywhere near this area. The size, wind resistance ratings, amount of ICF walls/floors, geothermal heating and air, and overall complexity and grandiosity of the home are beyond compare. This home pushes the limits of what can be done architecturally and structurally for high-end custom homes.”