Understanding Waterproofing Terminology

Storm Waterproofing Can Help You Waterproof Your Basement in Baltimore

When it comes to basement waterproofing, there is a lot to know. That’s why we want to make things a little less confusing for you by providing some terminology and definitions. At Storm Waterproofing, we provide the information you need so you are informed throughout the process. Read on to learn more about our industry.

Storm Waterproofing’s Comprehensive Glossary

View our glossary and contact us for more information.

Above-Grade Waterproofing    

Above-ground waterproofing prevents dampness from accumulating. Dampness can destroy part of the structure and any property in the basement.

Absolute Humidity

Absolute humidity is a measurement of the amount of water vapor present in a unit volume of air.


Absorption is a term describing the accumulation of water or vapor drawn directly into your home’s structure’s cells.


Foundation movement can release silt into the basement, along with water. The sediment is acidic and further decays your foundation.

Active Soils

Active soils are non-load bearing soil mass that is moving due to changing moisture levels.


A brick or building material made of sun-dried earth and straw.


A conduit for carrying a large volume of flowing water.


The material used to fill in an excavation.


An excavation machine with a large bucket used for digging and backfilling around the exterior of the foundation in certain types of waterproofing processes.


The solid rock layer under the surface of the soil.

Below Grade

Any part of the house or structure that is underground or beneath ground level.

Black Mold

A type of mold that can be toxic if inhaled.


Bleeders are a useful tool for keeping your basement dry. Usually constructed from PVC pipe or concrete, this pipe acts as a drain, releasing water from outside the foundation into basement drain tiles, which prevents the water from entering and settling in the basement itself.

Bowing Walls

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

Capillary Action

This is the natural action by which water when in contact with a porous surface, is drawn to and absorbed by that surface. Your concrete basement floor and walls are such porous surfaces. Their porous nature allows them to absorb water like a reservoir, ready to burst. A basement can absorbed as much as 240 gallons of water during an average rainstorm.

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.

Carbon Fiber Strips

Pieces of carbon fiber material are another basement waterproofing product that, when bonded to a wall, will not stretch. These strips, when installed correctly, will stop cracks from growing but must be used before the damage has progressed too far, creating a leaking basement wall.

Check Valve      

A basement waterproofing product device that permits water flow in only one direction and is commonly installed in the sump pumps discharge line.

Clay Soil             

Soil, which is composed of very fine particles, usually silicates of aluminum and/or iron and magnesium. Clay soil impedes the flow of water, meaning it absorbs water slowly and then retains it for a long time, causing a wet basement. Wet clay soil is heavy and sticky, tending to swell from the added moisture. When dry, clay soil shrinks and settles. The top layer can bake into a hard, concrete-like crust, which cracks.

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.

Concrete Block

Concrete block is commonly used in nominal 8″, 10″ or 12″ widths and is typically 8″ tall by 16″ long with two open cells in the block. The concrete blocks are stacked with alternating vertical joints using mortar between the joints to hold the block together.

Cove/Wall Cove

This is the joint where the wall and the floor meet. This is also a common area for water intrusion, causing a wet basement.

Damp Proofing

An application or system that is installed when the house is built to resist water vapor or minor amounts of moisture and acts as a backup to primary waterproofing systems. Damp proofing materials are basement waterproofing products subject to the effects of weathering and deterioration and are not effective against water pressure.

Discharge Line

The pipe used to direct the water away, often from a sump pump. Discharge lines should be checked periodically to ensure there are no obstructions that might restrict the water flow. Long discharge lines will freeze under the right conditions and should be kept as short as possible in northern climates.


A pipe that moves water out of a home’s gutter system and away from the foundation and walls of a home or building.

Drain Tile

Previously made of clay and other hard materials laid end-to-end, drain tile is now commonly made of flexible, perforated polyethylene tubing and is laid near the footing level to aid in the control of a wet basement.

Drain Tile Test

The drain tile test is performed by cutting through the floor slab to access the drain tile, flushing water into the drain tile, and observing the amount of water entering the sump pump crock. A diminished water flow indicates a plugged or crushed drain tile.

Drainage Systems

Consist of an interior drainage system and exterior drainage system to reduce excess water around and below the foundation.

Dry Lock

This is a vapor barrier for basements, attics and crawl spaces.

Dry Well

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.


White mineral deposits showing on the face of masonry due to water leaching through the masonry to the dry surface. This is usually evidence of a leaking basement wall.


One of the basement waterproofing products used to repair cracks in concrete or masonry. Epoxy is a material that can be injected into wall cracks and, when cured, forms a very strong bond with the base material. Epoxy can be used for the structural repair of a leaking basement wall.


Removing earth or dirt via digging.

Expansive Soils

Soils that swell when exposed to moisture. These swelling soils typically contain clay minerals that attract and absorb water. Another category of expansive soil known as swelling bedrock contains a special type of mineral called claystone.

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.

Exterior Waterproofing

A waterproofing method performed on the exterior of a home, yard, or the surrounding area. It keeps water from entering foundations and directs water away from the foundation. Exterior waterproofing includes an exterior drainage system, erosion control, proper gutters, downspouts, and crack repair.


This is 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.

Foundation Cracks

This is defined as fractures in concrete walls or slabs generally derived from differential settlement or lateral pressures.

Foundation Movement

It is an apparent post-construction movement of a foundation system that is detectable by changes in elevation accompanied by visible signs of distress, such as drywall cracks, doors out of square in their frames, concrete cracks, etc. These changes are necessary in order to confirm that movement has occurred after the original construction was completed.

Foundation Wall

This is the supporting portion of a structure below the first-floor construction or below grade.

Freeze-Thaw Cycle

This is the cycle of water freezing and later thawing and the effects it has on the material it is around or absorbed into is often a contributing factor to a wet basement.

French Drain

This drain works to move surface water away from a specific area.


A situation where a foundation is raised in affected areas higher than its normal elevation due to expanding soils.

Hollow Block Foundation

Block walls that have open hollow cavities designed within the block. These cavities allow water to collect inside the walls and cause a leaking basement wall.

Horizontal Cracks

Usually associated with bowing or displacement of masonry walls that are not plumb vertically and/or horizontally. Usually, the cause of a leaking basement wall.

Hydraulic Cement

A basement waterproofing product sometimes referred to as “Hot Patch” because of the heat generated during its exceptionally quick curing time, often used to patch cracks and small areas that have minor water seepage. May come loose during movement or settlement.


These are specific chemical qualities that enable the absorption or drawing of water.

Hydrostatic Pressure

This is still water pressure that is often caused by a high-water table. It is the pressure exerted against the foundation by various heights of water at rest. The same type of pressure you feel when you try to push a bucket into a pool of water. To some degree, this is the same pressure that allows ships to stay afloat. Hydraulic pressure is the main cause of a wet basement.


The inadvertent leaking of air and moisture, water, or water vapor into a structure.

Iron Bacteria

An orange-colored slimy substance, often mistaken for clay residue, that can clog drainage systems and sump pumps. It is actually a bacterium mold that feeds on the nutrients (iron ocher) of the flowing water. Chemical formulas, such as “Iron Out” will release the bacteria. Another way to release the bacteria is by flushing the system with hot (140 degrees) water.

Laser Level

An instrument, which emits a beam of light on a certain horizontal or vertical plane. This plane can be used to measure the deflection and/or movement of an adjacent plane.

Lateral Pressure

This is the pressures exerted upon a wall by surrounding soils.


A flexible elastomeric material applied to the exterior of the building.

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.

Monolithic Floor

When the floor and footing are poured together and become one single unit, the walls are then built on top of the floor. This is usually evident in a block foundation when the first block is a whole block with a mortar line under it on top of the floor.

Mortar Joint

This is a brick that’s secured to another similar brick or bricks by means of mortar or grout.

Negative Hydrostatic Pressure

When water is drawn from an area of high pressure, such as the soil surrounding a foundation, to an area of lower pressure, such as the interior of a basement. Below-grade interiors are particularly subject to this type of water pressure.

Palmer Valve

This is a stormwater discharge valve typically located in the sidewall of the floor drain, designed to prevent the backflow of sanitary sewers into the stormwater system.


A projection of masonry or a filled cell area of masonry for the purpose of bearing concentrated loads or to stiffen the wall against lateral forces.

Plumb Line

Tool for measuring wall deflection consisting of weight and string. The string is attached at the top of the wall, and the weight is at the end of the string located near the floor, providing a straight vertical reference line. Measurements are taken from the string to the wall to determine the amount of horizontal deflection in the wall.


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

Poured Concrete Foundation

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.

Poured Walls

Solid concrete walls that are constructed by setting concrete wall forms, installing steel reinforcing bars, and pouring concrete into the forms to create a wall.

Pressure Relief System

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.

Quick Patch

A quick curing, rigid, concrete repair fluid. It is extremely strong 4,700 psi but still remains slightly flexible with 35% elongation. Bonds permanently to concrete, wood, metals, fiberglass, and rigid plastics.

Radon Gas

Radon gas is an odorless and colorless, slightly radioactive gas that can seep into basements through floor or wall cracks. At certain concentrations, radon gas is considered a health hazard.


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.


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.


Described as substrate particles that are smaller than sand and larger than clay.

Solid Block Foundation

Block walls that are completely filled with cinder of concrete and have no hollow cavities and usually leak at the mortar joints.


The crumbling or breaking off in small pieces of concrete or masonry. This is usually a result of the freeze-thaw cycle or deterioration (rusting) of reinforcing steel or tie-rods.

Spud Pipe

Steel pipe, 3/4″ to 1″ diameter that is driven into the soil around the perimeter of the building. Water is injected into the soil through the pipe just above the elevation of the drain tile to test the function of the drain tile.

Steel Restraints

Wall reinforcing used to prevent further movement in basement walls. Steel restraints are typically composed of steel tubes placed vertically against the basement walls at a 32″ or 48″ spacing.

Step Cracks

Cracks in masonry walls that follow the vertical and horizontal joints in the masonry in a stepped fashion. Step cracks can be due to horizontal wall deflection, foundation settlement, or shrinkage of concrete masonry.

Stone Backfill

Clear crushed aggregate 3/4″ to 1″ diameter used to backfill excavations. Stone backfill allows for water to migrate easily towards the drain tile located at the basement footing elevation. Additionally, the stone backfill will have minimal settlement around the perimeter of the building after backfilling.

Stone Foundation

Walls made of large stones stacked on top of one another and usually held together with a mortar type substance. This type of foundation is usually older, and when the mortar deteriorates, it allows more water to pass between the stones and not only cause a wet basement but structural damage as well. Because the stones are not all the same size and shape, the interior side of the wall is semi-smooth, but the exterior side is not, which causes complications when trying basement waterproofing from the outside.

Sump Crock

Concrete, steel, or plastic basin placed below the floor slab in the lowest area of the building for collecting water from drain tile. Top rim to extend minimum 1″ above the floor. Sump pump submersible or upright pump located in sump crock to pump water out and away from the building.

Sump Pit

This is the hole that is used to accommodate a sump pump and collect water. A sump well liner is placed in the pit to keep the hole from collapsing.

Sump Pump

Sump pumps are placed below the ground of the foundation. They are designed to collect and remove water using a discharge pump. After the water is collected in the tank, it is discharged away from the home.

Tensile Strength

This is the ability of waterproofing products to resist being pulled or stretched apart to the point of failure.

Thermal Movement

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


A rod (steel) used as a connecting member or brace to hold forms in place when pouring concrete walls that are clipped when removing the forms.


A term used for the repair of cracks that occur in the joints in masonry walls. Tuckpointing involves the removal and replacement of the mortar between masonry units where cracking along the joints has occurred.


To dig or wear away the base or foundation.

Wall Cove

A common location where water enters a basement, this term describes the location where a wall and floor meet.

Wall Deflection

The degree to which a basement wall is shifted due to outside pressure. This can result in cracks and water seepage.

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.

Wall Irregularities

Masonry wall corners or areas in the wall that have thickened sections. Examples of wall irregularities include foundations for masonry fireplaces and wall pilasters.

Wall Slide

The horizontal movement of the basement wall, usually occurring at the bottom section of the wall.

Water Leak

To let water or other fluid in or out through a hole, crevice, etc.

Water Management System

This system consists of a drainage network along the perimeter of the basement. It removes water from the walls and under the foundation and directs it away from the home.

Water Penetration/Infiltration

The condition where water enters the interior areas of a structure.

Water Seepage

Water that has penetrated through a porous material such as soil.

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.

Weep Holes

Holes generally drilled in the lower course of hollow block walls near the footing during basement waterproofing that allows water trapped inside the cavities to escape

Contact Storm Waterproofing Today

Storm Waterproofing has decades of experience waterproofing basements and repairing foundations. To learn more about our services and contact our experts today. We can help restore balance and security to your home. Contact us today.

Why Choose Us?

  • We are fully licensed, bonded, and insured
  • We have over 20 years of experience
  • We offer free estimates
  • We offer transferable lifetime guarantees
  • We are built on 3 generations of basement waterproofing experience
  • We offer 24/7 emergency service
  • We use state-of-the-art waterproofing techniques