Precast concrete foundation and wall panels can take many forms. Some consist of steel-reinforced concrete ribs that run vertically and horizontally within the panels. Others are solid precast concrete panels. Panels are precast and cured in a controlled factory environment so that weather delays can be avoided. A typical panelized foundation can be erected in four to five hours, without the need to place concrete on site for the foundation. The result is a foundation that can be installed in any climate zone in one sixth of the time needed for a formed concrete wall.
Some manufacturers cast the concrete against foam insulation, which provides the form during manufacturing and added R-value in the wall. Panels range in size from 2 inches to 12 inches in width, by 8 inches to 12 inches in height and are typically installed with a crane on top of 4 inches to 6 inches of compacted stone. The stone facilitates sub-slab drainage and adequately carries and transfers the load from the foundation wall. Panel connections consist of bolts and sealant. The foundation can be backfilled as soon as it is braced per manufacturer’s specifications.
The controlled temperature of the processing plant allows the manufacturer to work with concrete admixtures that focus on ultimate strength rather than cure time and temperature. Manufacturers are able to produce mixes that harden to 5,000 psi, which is stronger than concrete blocks or concrete walls formed and cast in the field. Better control of the concrete mixture and curing environment allows the use of low water/cement ratios, which results in a dense material that prevents water penetration.