Drilled Bell Bottom Piers

Bell bottom piers are constructed in place under your foundation. Special equipment is required to drill a hole into the soil at an angle beneath your foundation.

A special device is used, after the hole is drilled to enlarge the bottom of the hole. It is the wider area at the bottom that carries most of the weight of the foundation it supports. The enlarged area at the bottom resembles a bell when viewed at a side angle. That is where this system gets it’s name.

A framework made up of re-bar is then inserted into the hole. The rebar extends from the top to the bottom providing reinforcement. The hole is then then poured full of concrete and allowed to cure. This curing process takes time and must be complete before work can continue.

It usually takes about 2 weeks of curing time before the foundation can be supported. Trying to support the weight of a foundation on this type of pier before it cures could result in the pier being crushed.

This pier type also requires the greatest amount of soil removal, most of which must be hauled away. The maximum depth that the pier can reach is limited by the equipment that is used to drill the holes. In some instances the total depth of the hole may not be sufficient to reach beyond the soil that is causing the problem. This will result in the pier not being able to provide proper support.

Another issue with this method is the fact that the pier must be drilled at an angle because the equipment that drills the hole must sit outside the foundation. This results in the weight of the foundation not resting directly in line with the enlarged "bell bottom" of the pier.

This type of pier is sometimes installed before the foundation and slab is poured. This is done as a preventative measure to guard against future problems. You still have concern of limited depth, if it is not great enough to reach stable soil providing proper support the foundation could end up with a large weight attached to it that is itself sinking and pulling your foundation along with it.

If a foundation with pre-installed bell bottom piers fails, repair can be very expensive. Freeing the foundation from the attached bell bottom piers in order to be able to raise it properly requires additional work.

If you plan on using this pier type then you should make sure that there is a very clear reason for doing so. Do your research and if you feel that your reasons for going this route, outweigh the risks, then go for it.

If you are not sure which way to go, you should seek the advice of a professional who has a background in foundation repair issues.

Pros

• Expensive
• Extremely long installation times

Cons

• Expensive
• Not installed directly beneath foundation
• Greatest impact on areas near installation
• Does not provide support directly beneath the foundation