After hurricane Sandy, many people are considering a literal “house lift.” This is more common than you would think, and is a great alternative to completely demolishing a home and building new one. Typically if you are in a flood zone, your soil conditions are not adequate for standard concrete footings and foundation. This means the amount of weight the soil can support is minimal. Usually the soil is muck, bog or silt. To support a house in these conditions, we either use timber piles or helical piles. Timber piles are treated lumber that look like telephone poles. They are pounded into the ground until they get to a depth where the soil can support the intended weight. Then, a concrete “grade beam” is poured over the tops of the piles. Unfortunately, the pounding can cause a lot of damage to homes in the immediate vicinity. For this reason, we use helical piles or “screw piles” more often. Screw piles are heavy steel rods with plates on the bottom which are actually screwed into the ground. Extensions can be added to achieve greater depth. The torque or “twisting force” dictates the amount of support each screw pile will offer.
Once driven, a plate is mounted on top and concrete is poured over it to support your home. In some cases they have a bracket which will attach to your existing foundation and give the support needed. So with all of that in mind, you can typically expect at least some alteration to your existing foundation.
All of the preceding work is done after the home is lifted. The process of lifting the building is the dramatic one; it is an engineering feat and the companies that specialize in lifts are truly skilled. Even with the most skilled companies doing the lifting, you will have stress cracks, repairs, etc. The building becomes more “saleable” and the flood insurance rates should remain low.