The possibility of the occurrence of foundation failure is something that everyone buying, selling, or occupying a home should consider. Foundation problems are commonplace, largely because the soil conditions, upon which residential and commercial buildings are constructed, tend to be very unstable in our areas. Our foundations are only as strong as the soil properties they are placed on. These soils are made up of thousands of years of sediments, mainly silts, clays and some granular soils. Also, Arizona has several large irrigated agricultural areas that have been turned into beautiful neighborhoods, most of which display evidence of foundation movement.
How do you know if you have a foundation problem? The following check list of symptoms should help you identify serious foundation movement: (1) Inspect for cracks in brickwork. Look for previous patching. Look for separation between door and windows and brickwork. Also, check to see if chimneys or porches are moving away from the house or structure; (2) Look for cracks in interior wall of ceiling finishes and/or tearing of wallpaper, floor coverings, etc.; (3) Check to see if windows or doors bind or stick or appear to be out of square; (4) Re-occurring leaks in your ceilings, around chimneys, or increases in your water bills.
If it is apparent that foundation failure has occurred, you should be aware that there are many different methods of repair available. They range greatly in cost, longevity, predictability and warranty. These methods are:
(a) 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.
(b) 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, however, it offers no stabilization value. The grout is bearing on top of the failed soils. It has 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 grout, which sometimes results in grout filled sewer systems, etc.
(c) Drilled Concrete Pier: The boring of shafts to a depth of 9 to 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.
(d) Driven Steel Piers: 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, it is usually billed by the foot, which 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 and offers no safety factors for lifting and maintaining compressive loads. It relies mainly on skin friction to support structure. It offers medium longevity with no warranty to performance.
(e) 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 8Oksi steel, connected with forged couplers as piers are advanced into a solid bearing strata several feet below the active soil zones. All 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 foundation. 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 system is the only system with ICBO (UBC) acceptance (ER-511 0). These piers can also secure your retaining walls, basement walls or other earth retention issues. They can be used in new construction as well as for remedial repairs.
If gutters are not in place, they should be. Make sure that they discharge at least 6 feet from
the perimeter of the house. Trees can affect a foundation's performance by removing large quantities of water from the soil. The severity of this problem is magnified if trees are planted too close to the structure. A rule of thumb is a tree should be, at a minimum, the distance of its ultimate height away from the home perimeter.
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.
