Glossary Of Common Basement Waterproofing Terms

Above-Grade Waterproofing – the waterproofing process that is typically used on above-ground basements in order to prevent dampness and water from accumulating and possibly damaging this part of the structure and its contents.

Absorption – the process wherein water or water vapor is drawn into and accumulates in the body or cells of a structure.

Backfill – the material used when filling in excavations or trenches against or around a basement, crawlspace, or foundation.

Basement – the floor or floors of a structure that are build completely or partially below the ground.

Basement floor slab – the concrete layer (usually 4” to 5” in thickness) that forms the floor of a basement.

Basement waterproofing – the process that is used to prevent a leaking basement wall and the seepage and accumulation of water on a basement floor.

Black mold – a mold genus that is associated with poor air quality within a commercial or residential structure. It is typically found after fungus begins growing on standing water that has accumulated within a structure. Individuals in the structure are exposed to this.

Bleeder – a drain pipe made from concrete or PVC that is used in basement waterproofing it is usually installed through the foundation to allow water to flow from outside a structure into drain tiles in the interior therefore preventing a leaky or wet basement.

Bowing walls – the result of excessive lateral pressure acting upon a building’s exterior. The pressure creates an inward movement that bows the wall and eventually leads to water leaking into the wall.

Capillary action – the migratory or wicking action of water into the pores of floors and walls of dry basement areas. The action is similar to the way in which a sponge draws water into it.

Carbon fiber – the use of material strips made from carbon fibers to waterproof basements. When it is bonded to a basement wall, it cannot stretch. It will stop the continuing growth of cracks if installed properly and prior to the cracking having progressed too far.

Caulk – a waterproofing material that refers to the process of applying it or the substance itself. In construction trades, caulk is normally used to close up gaps and joints in a structure.

Check valve – a device used in basement waterproofing. It permits water to flow in only one direction while being most commonly installed in the discharge line of sump pumps.

Cinder block – a pre-fabricated construction component that is made from cinders and concrete. Cinder blocks are most commonly used in the construction of foundation or retaining walls.

Cleat anchor – used to laterally support basement walls, this deadman is placed in soils that are classified as non-active, non-moving, or non-shifting.

Coating – any type of covering substance that is applied for changing a surface’s appearance or protecting it. The coating can be a gas, liquid, or solid and is oftentimes used to repair a leaky basement wall.

Cold Joint – the intersection between the end of poured concrete and the start of another concrete pouring is a cold joint. This is something that building contractors try to avoid by continuing to pour the concrete until the job has been completed.

Condensation – when moisture or vapor molecules are exposed to something colder, such as the air or other materials, they are converted into small droplets of water. This process is referred to as condensation and normally occurs on cooler basement floors, pipes, or walls just like on the exterior of a glass of cold water.

Cove/wall cove – the joint between floors and walls are known as coves or cove walls. This is one of the more common sources of water intrusion which will lead to a wet basement.

Cracked floors or walls – there are a number of reasons that cracks develop in floors and walls including contraction, expansion, settlement, and water pressure. In some cases, they are created by design. However, the crack is merely a symptom and not the actual problem. The problem is that water enters through those cracks whenever there is sufficient pressure to force it into penetrating the opening and causing a basement wall to leak.

Crawl space – the shallow and unfinished area beneath a structure’s first floor or its roof. It typically provides access to heating, plumbing, and wiring. If these areas are not properly ventilated, condensation will occur and the air will become stagnant.

Dampness – liquid that condenses or diffuses in small amounts on floors and walls. Moisture results from capillary action and/or condensation (see above) and can usually be controlled or corrected by creating adequate ventilation, heating the area, using a dehumidifier or a combination of these.

Dampproofing – usually installed when a home is being constructed, this application or system helps to prevent minor amounts of moisture or water vapor from accumulating. It is oftentimes viewed as a back-up to a waterproofing application or system. The materials that are used in the dampproofing process are waterproofing products.

Dehumidifier – a small appliance or device that enables condensation through the use of cold temperatures for squeezing the moisture out of air molecules into a removable tray that can easily be emptied when full. You should have a qualified building supply or hardware person size the dehumidifier for you based on your specific needs.

Discharge line – in most cases, this is a pipe that is used to divert the water away from a sump pump. You should periodically check these lines to insure that nothing has built up in them and is restricting the flow of water.

Downspout – the pipe that diverts water from rain gutters and away from the foundation of a home or other structure.

Drain tile – commonly made from a polyethylene tubing that is flexible and has been perforated, drain tiles were originally manufactured using clay or some type of hard material. These are laid in end-to-end fashion near the footing level of a basement in order to prevent the accumulation of water and wet basements.

Dry well – a gravel or rubble-filled hole in the earth that is used to correct or prevent a wet basement by diverting drainage water away from the structure.

Efflorescence – a white mineral that shows up as a deposit on the face of masonry. It results from water leaching through the masonry to the surface.

Epoxy injection – the injection of a lower viscosity epoxy or epoxy materials into the cracks in a foundation or wall. The material is prone to cracking if moving and settling continue to occur.

Exterior footing drain – a box, cylinder, or tube that is most commonly installed around the foundation footing’s outside perimeter. It collects and then diverts any water away from the structure’s foundation and is typically used when waterproofing a basement.

Flooring – a generalized term that is used to describe the covering of a floor.

Footing – the base upon which walls are constructed. It is developed by pouring concrete into a form or mold above the water table but below the frost line and then allowed to cure.

French drain – a subfloor system employed to divert surface water from an area using pressure to do so.

Heaving – the raising of a foundation above its elevation because of soil expanding after a thawing out period.

Hollow block foundation – as the name implies, these are hollowed openings within block walls. If water is able to collect inside, it will cause a leaky basement.

Horizontal cracks – typically related to the bowing and/or displacement of walls that are not horizontally and/or vertically plumb. This will cause basement walls to develop leaks.

Hydrophilic – specific chemical qualities that enable the absorption or drawing of water.

Hydrostatic pressure – oftentimes referred to as still water pressure, this is the pressure that is exerted against a foundation. It is caused by a high water table and when that water is allowed to rest against various heights of the foundation. This pressure builds up against foundation walls and beneath the floor after heavy rains.

Humidity – the moderate level of dampness or wetness that exists in the atmosphere. It causes condensation on basement floors and walls, eventually leading to the growth of mold.

Infiltration – the inadvertent leaking of air and moisture, water, or water vapor into a structure.

Lateral pressure – the pressure that surrounding soils exert on the walls of a structure. When the pressure becomes excessive, it can cause a basement wall to begin leaking.

Mildew – a mold pathogen that appears as a growth on the surface of its host material.

Moisture vapor drive – the moisture or water that wicks through concrete pores and delaminates the surrounding materials. This typically occurs on below grade and slab-on-grade floors.

Mold removal – as the name implies it is the process that is used to destroy or physically remove mold by using certain chemicals.

Negative hydrostatic pressure – occurs when water creates pressure the substrate’s opposing side and attempts to push through, thereby causing those materials to fail. Floors that are constructed below ground level are prone to this type of pressure.

Palmer valve – a valve used to discharge storm water. It is typically located in the floor drain side wall and is designed to prevent the backflow of sewage into the storm water system.

Polyurethane – a basement waterproofing material or product which is injected into the cracks in a basement wall to prevent leakage from occurring.

Poured concrete foundations – walls that are created by the pouring of concrete into forms that are normally held together through the use of tie-rods. The tie-rods are clipped as the forms are being removed. This area is prone to leaks that develop as a result of curing, thermal movement, and water pressure being present.

Pressure relief systems – drainage systems that are designed and installed below ground level to help reduce the negative impact of a wet basement that resulted from hydrostatic pressure building up beneath a basement floor.

Radon gas – a colorless, odorless gas that is slightly radioactive and can seep into basements through cracks in the floors or walls. Radon gas is considered a health hazard once it reaches certain levels in the air.

Sealant – a material that is most commonly used to secure joints on a building’s exterior. To work properly, sealants should be capable of withstanding the continual movement that occurs along joints without failing during all types of weather conditions.

Seepage water – water that infiltrates floor slabs and masonry walls. It is usually evidenced when a basement’s concrete flooring and walls become damp or start leaking. In most cases, this is due to the basement drainage system not functioning properly because it is overloaded.

Solid block foundation – when the openings in blocks are completely filled using cinder or concrete, there will be no hollow cavities. This is known as a solid block foundation. Any leaking that occurs will usually be found at joints in the mortar.

Stair step cracks or step cracks – a brick or block wall fracture that follows an upward path along the joints in mortar. Differential settlement or lateral pressure typically causes step cracks to occur and cause a basement wall to start leaking.

Steel restraints – wall reinforcement that uses steel tubing placed vertically against the walls of a basement to prevent further movement from occurring.

Stone Backfill – 3/4” to 1” clear, crushed aggregates used to backfill an excavation or trench. This allows water to flow towards drain tiles located at the elevation of the basement footing.

Sump pump – an upright, submersible pump that is used to pump water out of a structure and away from it.

Thermal movement – movement caused by contraction or expansion resulting from changes in temperature.

Vertical cracks – basement wall fractures that result from differential settlement or heaving walls.

Wall deflection – the amount of a basement wall’s horizontal movement with respect to the vertical plane of a given location.

Wall drainage board – a product used in the basement waterproofing process it is a panel that is made using corrugated or ribbed plastic and is placed at an angle against the wall and on top of the wall’s footing.

Water table – the uppermost level of a portion of land that has been completely saturated with water. Below grade leakage is attributed to the water table especially where basement coves, floors, and walls are concerned.