Foundation Repair Terminology

Foundation Repair Terminologyfoundation repair terminology

This glossary of foundation repair terminology is a resource tool to use when researching common foundation repair terminology methods. If you have any uncertainties about the foundation repair terminology process, contact us. We also invite you to read our Solid Foundation repair terminology blog as well as our FAQ page to gain a better insight into our approach to foundation repair terminology.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |


Active Zone – Depth of soil instability. Typically soil movement is due to variations in moisture. Also called the Seasonal or Weather Effected Zone.

Aeolian soil: Soil that has been deposited by the wind

Alluvial soil: Soil deposited by running waters.


Basal spacing: The distance between individual or molecular layers of the clay particles

Baseboard water channel: An interior basement drain unique to monolithic slab foundations. Monolithic basement slabs should not be broken out like concrete “floating” slabs.

Batter pier: A pile driven or a pier cast at a vertical incline.

Beam – When used in a pier and beam home, this term refers to a wooden member consisting of two or more pieces of dimensional lumber (such as 2’ X 6’ pieces) sandwiched together in order support the floor joist and the load of the structure. It is commonly referred to as a “girder.” Where slab foundations are concerned, a concrete beam is the thickest part of the concrete slab. It is generally installed around the perimeter of the foundation and traverses the slab in order to give it added strength and rigidity. The beam is reinforced with post tension cables or rebar.

Bedrock– A subsurface layer of earth suitable for supporting a structure.

Bell bottom: Enlarged bottom end of an augered pier to increase load bearing capacity. Typically limited to 3X the shaft diameter.

Below Grade – Below ground level.

Berm –
A heap of soil placed near a structure in order to direct the flow of water away from the structure. Berms can help prevent foundation damage and also enhance landscaping. They serve other purposes, too. For more information, study our drainage correction page.

Bentonite: Clay used as a heavy slurry to prevent the earth from sloughing into a drilled hole, or to aid in the removal of cuttings during drilling.

Brick ledge – Part of the foundation wall where the base layer of brick veneer is placed.

Brick lintel – Angle iron on which brick is placed. Used above windows, doors, and other openings.


Canopy: The diameter of tree foliage. Also known as “drip line”.

Canopy width – Distance across the spread of the branches and leaves of a mature tree.

Capillary fringe: An area that contains capillary water that originates from the water table.

Capillary pressure:
With references to soils, the negative water pressure at points above the water table. Sometimes defined as the difference between air and water pressures in pore space.

Capillary rise: A measure of the height of water rise above the level of the free water boundary. Capillarity is impeded by the swell of clay particles upon invasion of water. Finer soils will create a greater height of capillary rise, but the rate of rise is slower. The result of surface tension.

Catch Basin– A hole, dug at a distance from the foundation, then filled with gravel, sand, or other porous material. A catch basin is designed to work with a french drain to drain water away from the foundation. Water held in a catch basin evaporates or is absorbed into surrounding soil.

Clay – A naturally occurring mineral that is present in tiny particles. Clay traps and holds water within its molecules causing expansion or “swelling” of the soil. When water is withheld clay particles contract or “shrink”. Clay is also called Expansive Soil or Gumbo.

Clay Soil – This soil, which is commonly found in the DFW area, is “expansive,” meaning it gains and loses volume depending upon whether it is wet or dry. It is a naturally occurring mineral. Clay soil has a very strong absorption level and as a result, the soil can swell a great deal when wet. When the soil eventually dries, it shrinks (or contracts) and this causes foundation cracks. Clay is composed of hydrated aluminum silicates.

Concrete Breakout – A term used to describe what must be done when a pier is located in an area that is obstructed by a concrete surface such as a sidewalk or porch.

Concrete Piers – There are different types of piers made of concrete including poured concrete piers and pressed piers. (See “Pressed Piers” below)

Concrete Slab – Concrete that is typically poured in a single piece and serves as base support for a building. A slab foundation is reinforced with steel rebar and/or steel stressed cables, and other methods. Slab foundations may have footers made of the same materials. Required dimensions and components of slabs and footers may be dependent on local building codes. A concrete slab sits directly on surrounding soil. Also called Slab On Grade.

Consolidation – The change in soil volume due to the gradual loss of water. Where clay soils are concerned, this would result in shrinkage.

Crawlspace – A space that is approximately 18’-24” high and located directly beneath a structure such as a pier and beam house. The crawlspace is an area that one can crawl under. It should be vented in order to keep it from becoming too damp.


Deflection – The degree to which a structure is affected by a heavy load. In other words, the amount of bending or bowing that a foundation may exhibit.

Differential Moisture Content – A frequent source of foundation damage is the differential expansion of soil under and near the foundation repair terminology. Moist soil is adjacent to dry soil. Differential Moisture Content can be caused by low areas that hold water longer than surrounding areas, watering of lawns and garden beds, absence of gutters which direct water away from the foundation, water leaks, etc.


Elevation – The height of different points of your foundation repair terminology. The central point of an elevation is the level position. Anything higher or lower than that point would have a corresponding change in elevation.

Engineers Report – This is a report that is prepared by a licensed structural engineer outlining what is wrong with your foundation and what steps should be taken to repair it. The report typically concerns only those areas related to the substructure of the house. Many DFW cities require engineer’s reports before beginning the process of foundation repair terminology. Do you want to find out if your DFW city requires an engineer’s report? If so, please visit our foundation repair terminology permit resource page.

Exterior Piers – Foundation piers installed around the perimeter of a slab foundation repair terminology or pier and beam structure.


Fill – Soil or sand brought in to raise the elevation of a building’s foundation repair terminology and provide a level construction surface. Properly installed fill moves water away from the foundation.

Footing – A very thick concrete slab that is placed around the edges of a foundation. The purpose of a footing is to evenly spread the load (or weight) of the structure. It is usually 12-14” wide and is positioned under a perimeter beam. Footings are installed below grade (below ground level).

Form– Temporary structure, usually made of wood, built to hold concrete during the pour and initial hardening.

Foundation – The supporting layer of a structure. This part of your property comes in contact with the ground and everything resting on top of your foundation is supported by the soil beneath it.

Foundation Ties– Metal or plastic wires that hold the foundation panels and rebar in place while concrete is being poured.

French drain – Perforated pipe or gravel bed installed underground to catch and divert water from the foundation. A french drain is graded to drain the accumulated water away from the site.If land is flat a catch basin and discharge pump may be necessary to contain water.

Frost heaving: Expansion that results when a mixture of soil and water freezes. Upon freezing, the total volume may increase by as much as 25%, depending on the formation of ice at the boundary between the frozen and unfrozen soil.


Girder – A beam that is generally made of wood and whose purpose is to distribute the weight of the structure to the foundation resting below it. A double 2’ X 6’ girder is typically the minimum size used.

Grade – Ground level, or elevation at any given point. Excavation or building up then leveling of soil that will support a building’s foundation. Correct grading causes water to drain away from the building’s foundation repair terminology.

Grade Beam – A concrete support that wraps around the perimeter of a pier and beam foundation. It is generally poured  approximately 18″ below soil grade and reinforced with rebar.

Gravity discharge: Uses a natural or man-made slope in landscape to discharge water near the foundation.


Hydrostatic Plumbing Tests – Tests performed by licensed plumbers using special equipment to determine if a property has under-slab plumbing leaks that can cause foundation repair terminology damage. These tests are generally conduced before and after foundation repair terminology.


Interior Pier – A foundation pier that is installed inside the structure, as opposed to being installed around its perimeter. The pier is positioned under a load bearing wall or under an interior beam support.




Load Bearing Capacity – The maximum amount of weight that a foundation repair terminology can support without experiencing foundation failure. Too much weight will cause the soil beneath your structure to shift.


Moisture Content – This generally refers to the amount of moisture in the soil around your foundation. Soil with high moisture content expands.

Monolithic slab – A concrete floor and concrete foundation placed at the same time to form a monolithic footing and slab.

Mud Jacking – Procedure in which grout (typically a sandy loam, water and cement mixture) is pressure pumped under the foundation in multiple locations. Mud jacking is best used for small areas like driveways, sidewalks etc. It is not a good solution for a home or business foundation. The reason is that the applicator has no control over where the grout goes after leaving his equipment. The liquid material takes the path of least resistance so it can come up through the foundation in low areas and pipes that may not be firmly joined. In addition the back pressure from application can cause separation of plumbing pipes coming through the foundation repair terminology. Because application is uneven results aren’t predictable. Once the grout has set up it is as difficult to remove as concrete. Mud jacking also tends to be a temporary method of repair. In order for the grout to hold the foundation in position it depends on the soil beneath it to remain in place. If the soil moves due to loss of moisture then the grout will not be able to hold the load.


Negative friction: The effect on a pile of settling soil that may grip the pile and add its weight to the load to be carried by the bearing strata.


On Grade – At ground level

Osmosis: The transfer of water through a semipermeable membrane. The increased pressure caused by the diffusion of water is referred to as the osmotic pressure.


Permafrost: Refers to a condition where the subsoil remains continuously frozen.

Permeability – A measure of how easily water penetrates the soil. Test of soil permeability is called a Perc or Percolation Test.

Pier And Beam –
A type of construction that is generally used when building houses. Unlike homes built with concrete slabs, pier and beam structures are elevated and have a crawlspace beneath them. The crawlspace is usually 18-24” high and allows for easy access to the utilities beneath the house. Pier and beam houses almost always have wooden floors. To learn more, please study our pier and beam foundation repair terminology page.

Piers or Piering – Multiple steel posts are driven through unstable soil to bedrock. Then hydraulic jacks are used to stabilize the slab. The slab is held in place by the pier and the special bracket, attached to the pier, that holds and supports the slab.

Pile: Long, slender wood, steel, concrete or blended members usually driven in groups or clusters. They may also be poured concrete, which gives rise to the gray area of differentiation between piles and slim piers.

Piling: A pile or pier connected to a structure by one or more ties to facilitate lateral support and resist uplift. Also used for load testing.

Pile cap: A pile cap sets atop the concrete piling and is used to help disperse the weight of the foundation. This helps ensure the support system can handle the load, keeping the foundation from sinking into the soil.

Poured basement walls:
A standard slab wall. Susceptible to cracks from hydrostatic buildup.

Point Of Refusal – This describes how far piers can be pushed into the ground without breaking or causing the foundation to move in an upward position due to the hydraulic system being used to install them. Contractors push piers as far down as possible without negative results.

Pressed Piers or Pilings – Pre-cast concrete cylinders that are approximately 6” in diameter and 10” long that are hydraulically pushed into the ground to the “point of refusal” and stacked one of the top of the other. The weight of the house or structure is what keeps the piers in position. Their purpose is to stabilize a foundation. In the DFW area, they are typically driven 10-15’ into the ground. In some DFW cities, such as Irving, they may be installed as deep as 22’. Would you like more information about pressed concrete piers?



Rebar or Reinforcing Bar – Ribbed steel rods that are placed in forms of foundations, concrete walls, and footers. Concrete is then poured into the forms with rebar in place. Rebar strengthens the concrete.

Refusal – The condition reached when a pile being driven by a hammer has zero penetration per blow or when the effective energy of the hammer blow is no longer sufficient to cause penetration.

Root Barriers –
Barriers (or walls) that are created using plastic, plexiglass or metal that can withstand moisture and the effects of soil without corroding. The barriers are installed deep in the ground surrounding the foundation in order to prevent invasive tree roots from growing under the foundation and damaging it.


Settlement – When a structure’s foundation sinks down and “settles” further into the soil. This is also called “subsidence.” Poor soil compaction is one of the main reasons that a foundation will settle over a period of time.

Shear Failure – See Load Bearing Capacity.

Shims – Very thin (approx. ¼”) steel or wooden plates that are used to level a foundation repair terminology. They are placed between a support and the foundation and are used to just slightly change the elevation of the foundation.

Sill Plate – Bottom horizontal member of the exterior wall frame. The sill plate sits on top the foundation.

Skin Friction – The resistance of the soil surrounding a pile to vertical movement of the pile.

Slab Foundation – A  foundation made of concrete that is approximately 3-4” thick (on a residential property) and reinforced with steel rebar or post tension cables. The slab’s perimeter beams are generally 12” X 24” and made of concrete, too. These foundations are commonly called “slab on grade foundations.” Slab foundations are generally found in warm regions such as North Texas. Do you want read more about this? If so, please visit our slab foundation repair terminology page.

Soil Compaction – Soil particles that have been forced tightly together and have very few air pockets between them. Before a foundation is constructed, the soil beneath the foundation should be compacted with machinery that rolls across the ground, dispenses moisture into the soil, and then smashes it downward to make sure it’s stable and won’t sink under a heavy load. Poor soil compaction can result in settlement and foundation damage.

Soil stabilization: A procedure for improving the natural soil properties to make them a more adequate base for construction.

Steel Piers – Piers made of steel that driven all the way into the ground, to the point of reaching bedrock. In the Dallas-Fort Worth area, that may require that they be installed between 20-70” deep. While steel piers are excellent, they are considerably more costly than concrete piers. For more information, check out our steel piers resource page.

Stem Wall – The vertical part of a concrete or masonry retaining wall.

Stress: The force at a point in a soil mass that is due to the weight of the soil above the point plus any applied structural load.

Structural Integrity – Describes how structurally sound the foundation is and whether it can properly support the weight of the load as intended.

Sump pump: A device used to forcibly discharge intrusive basement or crawl space water out and away from the foundation repair terminology.


Thickened-Edge Slab – See Monolithic Slab.

Transpiration – When trees roots remove the moisture from the soil around your foundation.


Underpinning – The process of strengthening the foundation repair terminology of a house or structure. Foundation supports that are used to stabilize a structure and keep it in a level, vertical position. There are a vast number of underpinning systems, including pressed concrete piers and steel piers.

Under-Slab Plumbing Leaks – Leaks beneath your foundation repair terminology that you may not be aware of. They occur when there is a leak in your plumbing system and water seeps beneath your foundation. Water can cause major foundation damage.

Upheaval – Refers to part of a foundation repair terminology rising above its original elevation. Like settlement upheaval is evidenced by interior and exterior cracks throughout the building.



Wall anchors: Cost-effective, minimally invasive wall repair system that uses an interior wall plate attached to an anchor on the exterior of the home an designed to stabilize foundation walls by reducing pressure.

Wall braces: Supports bowing or buckling foundation walls from inside the basement without disturbing the outside of the home.

Wall shield: Liner used in basement homes to reduce air quality problems in brighten interior walls.

Water leaks: Water from any domestic source that accumulates under the foundation.

Water table: The upper surface of water saturation in permeable soil or rock.

Weep hole – A small opening left in the outer walls of masonry construction as an outlet for water inside a building to move outside the wall and evaporate.