The best foundation repair method depends upon the age and style of the foundation, the overall condition of the structure, the soil conditions and the goals of the property owner. During an evaluation by a Granite foundation repair specialist, we will explain the foundation methods and recommend the proper method or combination of foundation repair methods for your property. No matter how large or how small your needs are, we can help.
Eleven Common Foundation Repair and House Leveling Methods
Pressed steel piers or pilings
Helical steel piers
Pressed concrete pilings
Drilled or poured concrete piers
Belled concrete piers
I-Beam Retrofit for Pier and Beam Foundations
Void fill is seldom used in conjunction with any of the foundation repair methods. Void fill is accomplished by injecting a slurry of ash, cement and soil under the foundation after it has been lifted. If the clay soil is not at its maximally expanded state, the late intrusion of moisture will cause the void fill material to push the concrete slab. Urethane injection both fills a void and lifts the foundation at the same time.
Pressed Steel Piers provide optimal foundation repair for most homes in the Dallas Fort Worth area, with a typical depth of 22 feet and a maximum depth of 70 feet. These piers are normally driven to bedrock and permanently fix the foundation problem, eliminating any chance of foundation settlement. The pier is not practical in Houston, where the depth to bedrock may be 600 feet.
Helical Steel Piers are ideal for the repair of lightweight concrete slab foundations, pier and beam foundations and add-ons. The helical (spiral) plate with steel shaft is augered to a depth of 15-20 feet at a specified rotational torque resistance to assure that the pier is secured in solid soil.
Pressed Concrete Pilings consist of a stack of 6 to 8 inch diameter, 10-12 inch long concrete cylinders cured to 7000 PSI and driven to refusal. Typically10-15 feet deep in clay soils. Installation depth and quality is dependent upon the integrity of the contractor and installer. Steel cable and/or re-bar are added more to make the consumer comfortable, and provide minimal practical benefit.
Drilled / Poured Concrete Piers are created by auguring a hole 8-10 feet below the surface, installing re-bar, and filling the hole with concrete. Concrete cure time is 7-10 days before house leveling. Soil density is seldom tested, so the pier may later sink of its own weight.
Belled Concrete Piers are installed in a manner consistent with that of Poured Concrete Piers. They suffer from the same deficiency: seldom is soil density tested at the bottom of the hole, so the pier may later sink of its own weight.
Tunneling is actually a method of installing other pier types. When it is necessary to install piers on the interior of a structure, tunnels may be dug to eliminate the need to create holes in the floor. Tunneling is ideal to preserve expensive wood, marble and stone flooring.
Drainage Correction using French Drains, surface drains, or slope correction are a sound techniques to solve foundation problems caused by clay soil induced heave or upheaval. It may require 1-2 years for the wet clay soil under a slab to dry and shrink, but is preferable and costs far less than raising the whole foundation to the wet clay soil elevation.
Mudjacking is performed by drilling holes in a foundation and raising the concrete foundation by Pressure injecting a slurry of concrete, soil and ash. Mudjacking does not increase the strength of the foundation. Should the soil under the mudjacked foundation continue to consolidate or drop, the foundation will fail.
Soil Injection involves injecting a chemical stabilizer to a depth of 6 to 10 feet to make clay soil chemically inert to changes in moisture. Chemical stabilization works best during site development, prior to foundation construction.
Urethane Injection is a high tech form of mudjacking. A two part urethane material raises the concrete foundation by the process of a chemical reaction that turns the materials into a foam. Should the soil under the urethane foam raised foundation continue to consolidate or drop, the foundation will fail. Urethane foam does not increase the strength of the foundation.
I-Beam Retrofit for pier and beam foundations may be needed when the existing beams are inadequate to provide foundation support. More common and less expensive is to bolt channel steel to a beam to increase strength, as may be needed when a second story is added.
Root Barriers stop roots from extending under a foundation. Roots remove moisture causing the soil to drop, and may grow to heave the foundation. Some root barrier material is porous, containing chemical root repellants, which last up to 15 years. One such material is Bio-Barrier.