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Use precast concrete foundation panel
Dear Ms. Builder: My husband and I are in the planning stages of our new house. We are considering using a precast concrete foundation. The builder says that it is better and can be built faster. Is this correct? - Karen J.
Dear Karen: It sounds as though you have a very progressive builder who understands the advantages of using precast concrete panels. This is particularly true if you plan to have a basement that you will finish for living area. Precast concrete panels can also be effective for aboveground walls in warmer areas with no basements.
Precast concrete panels have been used for many years in commercial and industrial construction, but it is a newcomer to residential construction. New construction methods are always much slower to diffuse into residential construction. This is due to reluctance of many builders to accept new methods and to the hesitance of inspectors to change building codes.
Make sure that your builder has had some experience with this construction method. It is not difficult to erect the precast panels, but in order to realize all the advantages of this construction method, they must be level, aligned and properly sealed.
When you think about it, it makes sense to use precast concrete panels. They are made in a factory with strict quality standards and controlled conditions not subject to rain, hot and cold or builder errors. Most of the panels use superstrong 5,000 psi (pounds per square inch) concrete instead of 3,500 psi concrete commonly used in poured foundations.
Another advantage of using precast concrete is that it has steel reinforcing rod in all directions, not just horizontally around the band. Poured concrete foundations often have only a couple of pieces of reinforcing rod at the top and at the bottom.
In poor soil conditions, this can lead to future problems with cracks and leaks. If you and your builder do choose a poured foundation instead, ask for vertical reinforcing rods too.
You may have to do a little research to find a supplier of precast concrete panels in your area. They are very heavy and bulky, it does not make economic sense to ship them over long distances. Since your builder recommended them, he or she probably has a source for the panels.
If you have a problem finding them, contact these two major manufacturers of precast concrete panels - Superior Walls of America (800-452-9255) and Thermal-Krete (716-434-6157). They license many concrete companies across the country to cast their panel designs for them. Hopefully you can find one nearby to minimize transportation costs.
Even though precast panels cost somewhat more, there can be substantial labor savings. Once the foundation is dug and the crushed gravel base is laid (concrete footers are not always used) the entire foundation can be erected in one day. Crushed gravel formed a very stable base that distributes the weight of the house over a large area.
In contrast, concrete cannot be poured in the rain and construction delays can get costly. If a standard concrete foundation is poured in less than optimal conditions, the strength of the concrete can be compromised. There can also be cold joints where one pour of concrete begins to set before more is poured against it.
Even if you do not finish your basement or if you are using a crawl space, closed cell foam insulation panels on the inside of the panels will save energy year-round. Cavities between the formed concrete ribs provide space for wiring and plumbing. For additional insulation, the cavities can be filled with additional fiberglass insulation before finishing.
Many precast concrete panels, designed for residential foundations, have pressure-treated lumber nailers on the inside of the walls. This makes finishing it with drywall very easy. Owens Corning (800-438-7465) also makes a professionally installed wall insulation/finishing system for concrete walls.
Send your questions to Ms. Builder, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com/msbuilder.