Continuing where we left off, this is part 2 of our foundation repair glossary!
Negative Slope: Also known as negative grading, it is when the ground slopes toward your home, which will cause water to flow toward the foundation which can lead to water pooling and potential damage.
Non-Cohesive Soil: A soil in which there is no attraction or adhesion between individual soil particles
On Grade: At ground level.
Osmosis: The process by which water transfers through semipermeable material. Any increased pressure resulting from the diffusion of water is called osmotic pressure.
PE (Professional Engineer): Also known as ‘Licensed Structural Engineers’, as their name suggests are licensed professional engineers who design structures for safety and structural integrity. When dealing with foundation repairs they are needed to write an engineer’s report in which the corroborate the extent of the damage and the method needed for repairs.
Permafrost: A condition in which the subsoil of the ground stays continuously frozen year-round.
Pier: Solid concrete pillars that are strong enough to support and stabilize the foundation and the building that rests on top of it. The optimum pier diameter for residential structures is between 10-12 inches. They are hydraulically pushed into the ground to the “point of refusal” and stacked one of the top of the other.
Pier and Beam: A type of foundation construction usually used in residential buildings. Pier and beam homes are raised off of the ground and have a crawlspace under them. The crawlspace, normally at least 18″ high, allows access to the underside of the house, where utilities are located. These kinds of homes usually contain wooden floors.
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.
Plasticity Index (PI): A dimensionless constant which bears a direct ratio to the affinity of the soil for volumetric changes with respect to moisture variations.
Point of Refusal: When piers and piles are installed, they are forced or drilled into the ground until the density of the soil below them is too high to penetrate. The point where the pier or pile cannot be forced further into the ground is the point of refusal.
Polyurethane Foam Injection: This is a method used to lift concrete slabs and slab foundations by injecting expansive polyurethane foam under the concrete. The two-part urethane chemical expands into a foam when mixed. This mixture is injected through small holes under the foundation to fill in underground voids that have caused settlement. As it expands, it fills voids, lifting the foundation and compacting nearby soil to prevent further settlement.
Poured Basement Walls: Standard slab foundation walls. These walls often suffer from cracks due to hydrostatic pressure.
Push Piers: Push piers, also known as resistance piers, resistance piles, push piles, steel piers, steel push piers, or steel push piles, are part of a two-step system that lifts settled foundations. The piers resemble giant steel rods and are driven vertically into the ground until they anchor in stable soils deep underground. The piers are attached to the foundation with a bracket and the foundation is lifted hydraulically while supported by the piers. Once the foundation is lifted, the piers remain underneath to support it and prevent future foundation problems.
Rebar: A tension device added to concrete to form reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension.
Retaining Wall: Relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides.
Root Barrier: Barriers (or walls) made out of 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. Alternatively they can also be installed around the tree(s) in order to contain the roots inside and away from the foundation.
Screw Jacks: This floor leveling and crawl space repair solution consists of two steel tubes, one inside of the other. The inside tube is threaded like a screw and can be adjusted using a wing nut. This changes the height of the screw jack, allowing it to support and lift the above foundation of the home as a remedy for settled foundations.
Settlement: Sinking of the building’s concrete foundation. Settlement occurs naturally as the soil compacts over time but can occur unevenly if the soil was improperly compacted, or if other phenomena, such as erosion, soil shifting, or hydrostatic pressure occur. An uneven settlement is dangerous and can result in several structural problems throughout the building.
Shims: Very thin (approx. ¼”) steel or wooden plates that are used to level a foundation. They are placed between a support and the foundation and are used to just slightly change the elevation of the foundation.
Skin Friction: This is the resistance of the soil around your pier to the downward motion of the pier during installation.
Skirting: Exterior house skirtings are an element that can be used to beautify unsightly foundation walls or enclose the gap between the ground and the base of the home’s exterior walls. When wrapped around the home it becomes the foundation of a home’s visual appeal with a gorgeous, polished look.
Slab Foundation: A foundation made of concrete that is approximately 3-4” thick 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’.
Soaker Hose: A type of garden irrigation hose designed to deliver water slowly and evenly along its length. Unlike regular hoses, which release water at high pressure from a single outlet or nozzle, a soaker hose is made of porous material that allows water to seep or "soak" out gradually through small pores or holes along its length.
Soil: Soil is any loose material of the earth’s crust in various proportions. Soil usually contains water, air, and solid particles formed by fragmented rocks.
Soil Erosion: The process by which the top layer of soil, which is rich in nutrients, is worn away or displaced by natural forces such as wind, water, or ice, or by human activities like farming, construction, and deforestation. This can lead to the loss of fertile land, reduced agricultural productivity, and environmental degradation.
Soil Stabilization: Any process by which natural properties of the soil are improved, making the soil into a more solid base for construction.
Soil Compaction: The process by which the particles that make up soil are pressed together so firmly that they have few pockets of air between them. Soil compaction is a necessary step before foundation installation, and poor compaction of the soil might lead to foundation settlement and structural issues.
Stack Effect: Phenomenon that pulls warm air from the lower levels of the home, up-and-out through the upper levels of the home. In crawl space and basement homes, these means the indoor air consists of the same air coming from the basement or crawl space. Humidity, musty smells and allergens are often funneled up into the living space.
Stair Step Crack: Stair-step shaped cracks in the foundation, wall, or basement wall of a building. These cracks usually occur in brick, masonry, or block homes along the grout lines. If they are wider than 1/8 inch, they may be a sign of a foundation problem. However, they might also be due to normal foundation settlement.
Steel Pier: A slender column constructed of steel that can be driven deep into the soil, to the point of refusal, for foundation support (this is to the point of reaching bedrock).
Stress: The force at a point within the soil mass that exerts pressure from the weight of the soil above the point plus any pressure exerted on the soil by the structure.
Structural Integrity: Refers to how structurally sound the foundation and entire building are and whether the foundation can sustain the weight of the building.
Subsurface Moisture: Moisture below the ground level. This water can originate from several locations, including the water table, underground springs or aquifers, or nearby drainage systems.
Sump Pump: A device used to forcibly discharge intrusive basement or crawl space water out and away from the foundation.
Transpiration: The removal of moisture from the soil by vegetation i.e. nearby tree roots and other plants.
Underground Voids: Gaps or holes in the ground that form due to soil settlement or erosion. If voids form under the foundation of a building, the building will lack proper support and may settle unevenly, resulting in structural problems and foundation failure.
Underpinning: The foundation repair process by which steel piers (they can be helical piers or push piers) are installed under the foundation to stabilize the concrete and lift the sinking structure. In the underpinning process, the piers are driven point-first into the ground (or screwed into the ground in the case of helical piers) until they anchor in stable soils beneath the active soil level. The piers are attached to the foundation with a bracket and hydraulically lifted to solve settlement issues .
Under-Slab Plumbing Leaks: Leaks beneath your foundation 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.
Uniform Soil: Soil that contains a high proportion of particles with narrow size limits.
Upheaval: Lifting of the foundation due to pressure from shifting soil or varying soil water content under the foundation. This often occurs when the soil freezes and water in the soil expands, pushing the foundation upwards.
Vertical Crack: Any crack in a foundation or wall that runs vertically. These cracks are usually signs of foundation settlement.
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 and 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. Wall Shield is clean and efficient.
Water Leaks: Water from any domestic source that accumulates under the foundation.
Water Table: The level in the soil beneath which the ground is saturated with water. The upper surface of water saturation in permeable soil or rock.
Well-Graded Soil: A soil with a fairly even distribution of grain sizes—no excess of one size and no intermediate sizes lacking.
Wind Load: Any pressure on the structure caused by wind or weather. Again, while we don't expect you to memorize all this terms, being familiarized with them will help you to have a clearer and more comprehensive understanding of the possible situations you and your foundation might have to face. This will ensure transparency and empower you to make well-informed decisions regarding your foundation.
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