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).
3. Window openings are framed with treated 2x8s.
Sizes and location must be specified when the panels
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).
4. Precast haunches support frost walls that tie
into full-height foundation walls. Continuous haunches
can support masonry veneers.
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
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.