Construction

  • By BUILDER Staff
  • Source: BUILDER Magazine
  • Publication date: 2007-01-01

Despite the fact that concrete is a common structural material in Florida, precast concrete walls and floor panels are less popular, especially in the residential realm. As with other aspects of its design and operation, The New American Home 2007 stretches the industry by building with this panelized system—one that not only complies with strict regional codes for high winds and other extreme climate conditions, but also builds the shell in about one-third the time of a CMU system. When insulated, the precast structure delivers better thermal and sound-abatement qualities, as well.

It is, however, a less-forgiving system than a wood frame or concrete block, requiring the design-build team to be very precise with the locations of mechanicals, the placements and measurements of all openings, and the arrangement of finishes in and along the solid concrete wall and floor panels, as they are very difficult to manipulate in the field.

An 8-inch-thick central spine splits the street-level plan (above, top), providing a bearing wall between the sidewall panels for the 6-inch-thick, hollow-core floor panels (above, middle). The relatively thin floors (a wood-framed floor assembly would be twice as thick) enabled the 10-foot ceilings on the third level within the single-family height restrictions of the neighborhood, creating the loftlike feel for that space that reflects the style of the condos across Lake Eola. Much of the structural steel and concrete walls were left exposed inside, the latter cleaned and sealed (and occasionally acid-washed) to contrast with the frame walls.

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The garage is built using a combination of CMUs for the first-floor structure and light-gauge steel framing for the suite above. The frame is protected by an exterior housewrap and drainage panel behind the finishes (left).

PRODUCT SPECS
  • STEEL: Structural steel, left exposed and painted on the glass bridge and the open-riser staircase, adds an industrial feel and delivers tighter tolerances, respectively. Light-gauge steel frames the structure for the in-law suite over the garage. Provided by members of the Steel Framing Alliance. Circle no. 156.
  • FLOOR PANELS: Precast Hollowcore planks from Gate Concrete Products serve as the elevated floor structure. Circle no. 157.
  • PRECAST WALLS: A system of exterior structural walls, columns, and accessory components provided by Standard Precast (circle no. 158) form the shell of the house. The walls are insulated with a rigid Styrofoam extruded polystyrene panel from Dow Building Solutions (circle no. 159) for a superior thermal envelope that also delivers sound-abatement and pest control qualities. The Prestressed/Precast Concrete Institute (circle no. 160) and the Portland Cement Association (circle no. 161) spearheaded the use of the panelized system and provided consulting services and support.
  • PLUMBING SYSTEM: The FlowGuard Gold CPVC plumbing pipes and fittings from Noveon are corrosion and scale resistant, reduce condensation, deliver quiet operation, and maintain high water quality for hot and cold potable water systems. Circle no. 162.
  • HOUSEWRAP: PACTIV's GreenGuard Raindrop housewrap provides a perimeter moisture and air barrier for the second level of the in-law suite over the garage. The material features an integral drainage panel to direct moisture away between the sheathing panel and the exterior finishes. Circle no. 163
  • TOOLS: A full line of reliable power and hand tools from Hilti allowed crews to maintain the production schedule and solve just about any on-site challenge. Circle no. 164.
  • METAL CONNECTORS: Various metal connectors from Simpson Strong-Tie created a continuous load path through all framed sections to help the house meet strict codes for high-wind resistance and uplift loads. Circle no. 165.