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CFA Foundation Fundamentals

Positive Drainage…Curing Compound…Fluid Pressure? What were those words the foundation contractor used during our meeting yesterday? Construction projects, like so many other business endeavors, are not without communication problems between parties. Many are associated with terminology that is common to the contractor, yet distinctly foreign to the customer or owner.

Although the following list of frequently used terms is not exclusive to the foundation construction industry, these terms are certainly used often in that arena. Understanding them increases your ability to communicate with the foundation contractor and allows for a more satisfying project. By taking the time to learn some basic terms, you ensure your needs are met.


Concrete is composed of water, aggregates and cement. Materials other than these, generally liquid and not considered reinforcing, that are added to the mix before or during mixing are considered admixtures.


Material, such as gravel or soil, placed in an excavated space, generally around a foundation or retaining wall.


A partition in formwork blocking fresh concrete from a section of the form, such as at a construction joint or wall end.

Concrete, reinforced

Concrete that contains deformed steel reinforcement and is designed on the basis that the two materials act together in resisting forces.

Concrete, unreinforced

Concrete that does not contain reinforcement for structural purposes. It is also referred to as “plain” structural concrete. Such concrete may include horizontal reinforcement that is placed to reduce temperature and shrinkage cracks.

Curing compound

A liquid that coats the surface of newly placed concrete to retard the loss of water or reflect heat, providing an opportunity for the concrete to develop its properties in a favorable temperature and moisture environment.


A treatment of concrete to retard the passage or absorption of water or water vapor. Examples include tar or polyethylene sheeting.

Equivalent fluid pressure

The pressure applied to a construction from granular-like materials, such as soils, exhibited as a fluid-like force. The applicable equivalent fluid pressure varies for each type of soil.

Expansive soil

A soil that changes in volume due to variation in moisture content.

Flat wall

A conventionally formed concrete wall with flat surfaces.


A structural element that transfers loads directly to the soil.


The structural elements through which the load of a structure is transferred to the earth. Foundation wall The structural element of a foundation that transfers the load of a structure to the footing or soil. A foundation wall includes basement and stem walls.

Hydrostatic pressure

The force exhibited as a live load, applied by water acting on a surface.


A physical separation in concrete, including cracks, intentionally made or forced to occur at specified locations.

Joint, contraction

A groove in a concrete structure, either formed, sawed, or tooled, to create a weakened place to regulate the location of cracking resulting from the dimensional change of different parts of the structure. (Also known as a control joint).

Joint, isolation

A separation between two individual components of a concrete structure, usually a vertical plane, designed to interfere with the performance of the structure, yet allow movement in three directions and avoid the formation of cracks else where in concrete.


A recess or groove in one placement of concrete, which is filled with concrete of the next placement giving shear strength to the joint.

Lateral Pressure

The force exerted in a horizontal direction on a structural member.

Positive drainage

Grading used to control and direct the flow of water around and away from a structure.


A slab which is unreinforced or reinforced and continuously supported by ground, and whose total loading, when uniformly distributed, would impart a pressure to the grade or soil that is less than 50 percent of the allowable bearing capacity thereof.


A measure of consistency for freshly mixed concrete determined by measuring the amount of drop in a molded specimen of concrete immediately after removal of the slump cone.


Soil prepared and compacted to support a structure or a pavement system.

Unbalanced fill

The difference in height between the exterior and interior finish ground levels. Where an interior concrete slab is provided, the unbalanced backfill is measured from the exterior finish ground level to the top of the interior concrete slab.

Waterproofing Material

A long-term protection treatment to prevent hydrostatic water intrusion. Examples include elastomeric membrane or drainage with a bonded, crack-bridging coating or sheet; or an unbonded, elastic or semi-rigid sheet system.

Final Thought

Too often, miscommunication occurs between homeowners and foundation professionals because of a misunderstanding of terms. With a clear understanding of each others’ language, everyone clearly comprehends the project’s goal and objectives. Learning this language from the project onset creates a vehicle for clear communication. Open lines of communication begin when everyone is speaking the same language, and is the first step to ensuring a successful project.


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Concrete FACTS, a publication of the Concrete Foundations Association, is THE voice for residential concrete industry news, market intelligence, business strategies, technical solutions, product information, and other resources for professionals in the cast-in-place concrete industry. Subscriptions to Concrete FACTS is available to anyone involved or interested in the residential concrete industry as a service to your industry. Please contact CFA Headquarters to find out more about your free subscription or Email Us