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Unusual Conditions

Window openings are framed with treated lumber at the manufacturing plant. A full concrete stud is positioned at each jamb, and a 2x8 treated box forms the rough opening for the window (Figure 3).

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Figure 3. Window openings are framed with treated 2x8s. Sizes and location must be specified when the panels are ordered.

Doorways are framed in the same manner. To preserve panel strength, the lower bond beam is never cut at a door opening. This is not a problem, since the floor slab finishes out higher than the bond beam. To accommodate masonry veneers, haunches projecting up to 6 inches are cast into the panels. Stone veneers up to 8 inches thick can easily be supported. These haunchs are also used to support precast frost walls (an intersecting garage wall, for example) that tie into a full-height foundation (Figure 4).

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Figure 4. Precast haunches support frost walls that tie into full-height foundation walls. Continuous haunches can support masonry veneers.

Cost-Competitive System

The cost of the precast panels compares favorably to conventional foundations. According to David Weaver, who installs Superior Wall panels, the average installed cost for 8-foot-high wall panels is $36 per linear foot within 20 miles of the plant. An 8-foot poured wall costs about $38 per linear foot in my area (not including footings). Compared with poured concrete or block foundations, interior finishing costs are also much lower for the Superior precast panels. Dave Stoltzfus, of Elverson, Pa., has built over 200 homes using the panels, and realizes savings of up to 15% when finishing costs are factored into the cost equation.

Freight on Board

Trucking costs for the precast panels start to become prohibitive when the job site is located more than 200 miles from the plant. Currently, there are 14 plants manufacturing Superior Wall panels in New York, Iowa, Pennsylvania, Minnesota, and South Carolina. Manufacturers must be licensed; direct inquiries to Superior Walls of America at 800/452-9255. Seeing is believing. The foundation I watched being installed took about 90 minutes to set in place. Had the framers been there, they could have started setting sill plates before the crane pulled out.