Foundation Repair Glossary, The Entire List

As promised, here's our complete Foundation Repair Glossary in one great big list. Remember, if you have a question about any of these terms, be sure to ask us!

Active Zone

This is the depth of soil instability or movement, usually caused by changes in moisture. Sometimes, the active zone is referred to as the Seasonal Zone.

Bell Bottom Pier

A concrete pier that has a bell-shaped bearing surface.

Builder Piers

When the builder pours the grade beam for a pier and beam foundation, the builder piers are poured first. Builder piers are poured with a spacing of four to eight feet apart and to an average depth of three to four feet. These piers hold the grade beam in place. Sometimes builder piers fail, due to their low level of placement.

Clay

Crawl Space

The space between the bottom of the structure and the ground. This is common or necessary with pier and beam foundations. A properly engineered crawlspace allows enough room to vent moisture and allow for work on plumbing, electrical, and other utilities under the building.

Composed primarily of fine-grained minerals, clay is a naturally occurring component of soil. Clay expands greatly when mixed with water but then significantly contracts when water is withdrawn. Soil expansion and contraction is one of the leading causes of foundation failure.

Deviation

Deviation is the amount by which the structure is not level. That is, the structure has deviated from its specifications and true level. Naturally, a home with a great deal of deviation requires more work (piers) to bring it back to level.

Differential Settlement

The difference in movement vertically between different parts of the foundation; Non-trivial differential settlement can cause foundation failure.

Drilled Pier

Drilled piers involve drilling a hole at an angle to a predetermined depth under the slab, then using rebar to build a form in, then filling in the hole with concrete. If the conditions that caused the foundation to fail in the first place aren't remedied, then it's highly likely that the drilled pier will fail in time.

Elevation

Elevation is the series of measurements used to determine the difference in height between a central point and other points.

Engineers Report

An engineering report is done after a foundation has been repaired or before a structure is purchased. The report determines whether or not the foundation can perform its intended function and whether or not any remedial foundation repairs are necessary. In Texas, the report is a level "B" investigation (as described by the Texas Board of Professional Engineers and the American Society of Civil Engineers). The report will be sealed and signed by a Professional Engineer. The engineering report usually includes: Foundation Analysis, Interior Observations, Exterior Observations, Conclusions, Recommendations, and Photo File.

Epoxy Injection

Epoxy injection is used for concrete in manner similar to how welding is used for steel. That is, epoxy is used to fill cracks in concrete; often times, though, the cracks remain as weak point in the foundation.

Footing

Footings, typically constructed of steel-reinforced concrete, is the bottom part of the foundation. The footing spreads the vertical loads from the building sitting on top of the foundation. With slab foundations, the footing is usually two feet and runs the entire perimeter of the slab.

Foundation

A home foundation is that part of the structure that is in direct contact with the ground. The foundation transmits the weight of the entire home and itself to the supporting soil.

French Drain

A drain that is used to collect water that migrates under ground. It is not used to collect large amounts of water from a heavy rain fall. French Drains are usually dug down 36-48 inches. Then 1 1/4” river rock is placed at the bottom of the trench and a 4” corrugated pipe is placed over this rock. Once in place, the trench is filled with river rock to approximately 4-6” below grade. The last 4-6” are then topped with soil and/or sod.

Galvanizing

Galvanized metal is made via an electromechanical process by which steel (or iron, or other metal) is coated with a non-rusting metal, such as zinc. The zinc simply isn't painted on the steel but rather is deposited and bonded to the steel via electrode position. The long and short of it all is that the steel is protected by the zinc and not subject to rust.

Grade

The level of ground surface. The grade can also refer to the rise or fall of the ground over a given distance.

Grade Beam

The grade beam is the concrete support that goes around the perimeter of a Pier & Beam foundation. This is what home and bricks are supported by along the perimeters. The concrete grade beam is, on average, poured 18-20 inches below soil grade and is reinforced with rebar laid inside the concrete for additional support.

Helical Pier

A helical pier is a steel shaft to which circular steel plates have been welded at an angle (thing of a large screw). Helical piers offer more resistance and support than traditional steel piers, which do not have steel plates.

Initial Site Inspection

An initial site inspection determines the most likely cause of damage and if it's caused by the foundation. The initial site inspection requires the inspector to gather lots of information including but not limited to structural and architectural drawings, grading plans, and plat of survey.

Jacking

A method by which a static driving force is performed on a pile by jacks.

Live Load

This is the additional weight added to a structure by people, furniture, snow, ice, water, etc.

Mudjacking

A foundation repair process used by some foundation repair businesses where water and soil cement or soil-lime-cement grout is pumped beneath the slab to lift the slab to the desired position. We recommend mudjacking only for flat concrete surfaces such as garage floors, driveways, pool and patio decks.

Pier

A support under a structure's foundation. Piers can be made of wood, steel, concrete and sunk into the ground or resting atop ground (for smaller structures).

Pier and Beam

A foundation construction method where the structure is supported several feet off the ground by pillars and posts or pilings (a.k.a. the piers).

Pier Depth

The depth to which piers are sunk. Piers must reach a depth that provides adequate support. This means to bedrock or to a particular soil density. The deeper the piers must be sunk, the more expensive the foundation repair job will be.

Post-Tensioning Cable Foundations

A foundation construction technique where high-strength steel strands or cables, typically referred to as tendons, create a grid of steel cables that actively support the slab.

Pressed Pier

A pressed pier is made up of individual pilings that are pre-pressed and pre-formed. These pilings, in turn, are pressed into the ground using a hydraulic press. The individual pilings are locked to each other with steel shims or a piece of cable.

Rebar

Rebar, also known as reinforcing steel or reinforcement steel, is a common steel bar used to reinforced concrete.

Refusal

The condition reached when a pier can't be driven any farther, like when the pier reaches an impenetrable bottom such as rock). The term refusal may be used to indicate the specified minimum penetration per blow. Driving piers beyond refusal can damage the piers.

Retaining Wall

A retaining wall supports eroding soil in areas where the ground is likely to shift. Retaining walls can also provide additional support to foundations built up with fill dirt.

Root Barrier

Root barriers are physical barriers that redirect tree root growth downward, thus eliminating surface rooting that can damage foundations, sidewalks, driveways, and other hardscapes

Settlement

Settlement occurs when a part of the foundation drops below the original as-built grade.

Slab

A concrete foundation supported entirely by the surface soil. Slab foundations are popular in most new residential construction in areas with high-clay soils, such as that found in north Texas and southern Oklahoma.

Soaker Hose

A gardening hose capped on one end and containing hundreds of tiny perforations. A soaker hose set next to a structure's foundation can help maintain a consistent moisture level within the soil and help prevent foundation movement and, consequently, foundation failure.

Soil

The collection of loose material, including air, water, and solid particles, comprising the Earth's crust. It's comprised of a mixture of mineral and organic materials in solid, gaseous and aqueous states. When discussing foundation construction, maintenance, and repair, we are most concerned with the moisture content of the soil.

Soil Stability

Soil material (clay, sand, etc.) and drainage play a big part in how much water the soil can contain and how often that soil is asked to contain that water. If the soil's moisture content changes often and/or a great deal, your foundation will move as the soil contracts and expands with moisture.

Soil Stabilization

This is the process by which a contractor improves the natural properties of soil to make it a better base for construction. Soil stabilization reduces or eliminates erosion, controls the movement of water through a given parcel of soil, and seeks to moderate the soil's moisture content.

Structural Engineer

An independent registered professional engineer that specializes in civil or structural engineering.

Subsidence

The sinking of all or part of a structure's foundation.

Sump Pump

A pump which removes water from a sump pit. (The sump pits simply a hole into which water is drained; the sump pit is commonly found in the basement.)

Upheaval

The lifting of all or part of a structure's foundation.

Void Filling

A low pressure injection of grout slurry that fills the space between a foundation and the soil beneath the foundation.

Waffle Slab Foundation

Waffle slab foundations are formed when beams are poured throughout the interior until the pattern resembles a waffle.>

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