Foundation Repair Methods
There are two general classes of foundation repair; deep, and shallow. Deep repairs, sometimes referred to as underpinning, mostly involve pushing or screwing steel piers into the ground to transfer the support and lift structural elements of a foundation. Shallow repairs can be used to address slab-on-grade foundations such as floating slab floors which have settled. Soil modification is a mid-depth repair typically performed in conjunction with shallow repairs.
Deep repairs are most frequently used for lifting concentrated loads, such as footings, and for bypassing unstable layers of soil which are causing recurrent problems with a foundation. Deep foundation repairs involve transferring the your foundation’s weight to a different layer of ground than it was originally built to sit on. We install two different types of deep foundation repair systems:
Helical piers are screwed into the ground to transfer the weight of your foundation to a more stable layer of soil. The weight of the structure is transferred to the deep soil by the helices (rings) of the piers.
Push (Resistance) Piers
Push piers, also called resistance piers, are pushed into the ground against the weight of your foundation. Push piers are primarily designed to be end bearing, so they are pushed into the ground until the tip of the pier runs into a layer of soil hard enough to push against to lift the foundation. Push piers can either be eccentric (mounted on the side of a footing) or concentric (installed under the center of the foundation).
Shallow repairs are best suited for lifting non-concentrated loads such as slab floors. Both shallow foundation repair processes we perform involve injecting material immediately under the foundation concrete to fill voids and raise the foundation as required. The least appreciated of foundation repair methods, shallow repairs are often much more economical and reliable than deep repairs for slab foundations. We perform two types of shallow foundation repairs:
Foam jacking is used to raise and support slab portions of foundations, such as interior floors. High density polyurethane is injected under the foundation, where it expands and pushes the foundation back into place. We utilize foam jacking in place of slab piers.
Slab jacking is used to raise and support concrete slabs, generally outside. Slab jacking repairs settlement by injecting sand-based grout below the concrete to fill voids and raise the concrete.
Soil modification changes the properties of soil to make it more suitable for bearing the weight of a foundation or structure. It can be used to stabilize sinking foundations in place, when it is determined that the disruption associated with a deep foundation repair outweighs the benefits of mechanical lifting and stabilization, or in conjunction with shallow repairs where the problematic soil is relatively shallow, and a good candidate for soil modification through a chemical grouting process such as permeation grouting.