What would you think if a foundation contractor told you
that he could install your foundation in less than two hours?
You’d probably chalk it up to walking around too many job
sites without a hard hat.
But sometimes, seeing is believing. This certainly was the
case when I went down to southeastern Pennsylvania to watch the
installation of a Superior Wall foundation system. Superior
Walls of America, Ltd. (P.O. Box 427, Ephrata, PA 17522;
800/452-9255), manufactures a prefabricated foundation system
consisting of steel-reinforced insulated concrete panels that
are trucked to the site and set in place with a crane.
I was trained as a mason, and I’ve laid tens of
thousands of concrete blocks in conventional foundations. When
I first heard of the system, I have to admit I was a bit
skeptical. But after watching a Superior Wall foundation go in,
I‘m convinced the company has a first-rate foundation
system.
What’s in a Wall?
The panels consist of 2x8 concrete studs, sheathed with a
1-inch layer of extruded polystyrene insulation board and
covered with an exterior face shell of 2-inch concrete. At the
top and bottom of the panels, the concrete studs and face shell
are connected by concrete "wall plates" that serve as bond
beams.
The panels are factory-cast using a 5,000-psi
fiber-reinforced concrete, and are available in standard
heights of 4, 8, and 10 feet in lengths up to 12 feet. The
concrete studs are reinforced with a 3/8-inch vertical bar on
the interior (tension) side of the wall, and each bond beam is
reinforced with two 3/8-inch bars.
Site Preparation
A perimeter drain is placed a foot or so outside the foundation
footprint, and 6 inches of 1/2-inch crushed stone is spread
over the entire basement area and leveled.
| Figure
1. In areas where the panels will sit, the
gravel is compacted with a vibratory plate compactor,
then accurately leveled using a magnesium
straightedge. |