If it is apparent that foundation failure has occurred, you should be aware that there are many different methods of repair available. The following repair methods vary substantially in cost, longevity, predictability and warranty:
- Concrete Underpinning
Shallow concrete pads placed less than 3 feet under your existing foundation, used for additional support when settlement occurs. This method is costly, time consuming and offers only short-lived stability, as concrete pads are still bearing on unstable soils.
- Mud Jacking
The injection of grout under higher pressure to raise the slabs or foundations. Most commonly used to fill voids beneath slabs or leveling driveways, etc. Mud Jacking is moderately priced, but offers no stabilization value, in that the gout is bearing on top of the failed soils and no longevity. Also, it is crucial to understand that you are adding moisture to unstable soil in addition to a considerable amount of weight. In addition, in porous soils the grouter cannot control the flow of the grout which sometimes results in grout-filled sewer systems, etc.
- Drilled Concrete Pier
The boring of shafts to a depth of 9-12 feet, then filling them with concrete, used to offer additional support when settlement occurs, or to raise and level structures. Generally heavy external site disturbance with equipment and excavation and spoils removal. It is time consuming and unpredictable. Failure is possible if bearing on clays. It can actually be pushed up if placed in expansive soils. There are no guarantees and it is expensive.
- Driven Steel Piers (Push Pipe)
The hydraulic advancement of steel sections of low-grade tubing, to rock or permanent bearing strata, used primarily to offer additional support when settlement occurs as well as to raise and level structures. Minimal site disturbance. This product is sold as inexpensive, however, usually bills by the foot, whichs runs the cost up. With this hydraulic advancement system, no controls are given for tubing deflection, buckling or carry. It is leveraged by the building it is lifting. This offers no safety factors for lifting and maintaining compressive loads. Relies mainly on skin friction to support structure. Offers medium longevity with no warranty to performance.
- A.B. Chance Helical Piers
Helical piers are a slow-rotated, steel pier with various sized pitched plates that are installed below the existing foundation with minimal excavation, no spoils removal. Piers are constructed of high-strength 80ksi steel, connected with forged couplers as piers are advanced into a solid bearing strata below the active soil zones. All helical piers are installed using a solid bearing strata below the active soil zones. All helical piers are installed using a pre-engineered, torque vs. capacity process that insures solid bearing for the compressive load demands of the structure before structure weight is transferred to installed piers. Special haunch brackets are carefully attached to the existing foundations.
The weight transfer is carefully monitored as the structure weight is transferred to the pier shaft. All information is recorded and maintained. These piers are end bearing piers, meaning that all weight is transferred to the end of the pier, deep in stable bearing strata, and is not reliant on skin friction of the pier for support. This process is quick, cost effective, has minimal site disturbance and is a permanently guaranteed method for foundation repair. This is the only system with ICBO (UBC) acceptance (ER-5110).
These piers can also secure retaining walls, basement walls or other earth retention issues. They can be used in new construction as well as for remedial repairs.
If you feel you may have a foundation problem or know someone that does, or if you are planning to build a home and would like to secure yourself against these types of failures, call a professional for a consultation, survey and estimate.