This glossary explains common basement and foundation waterproofing terms in plain language for homeowners. It’s designed to help you better understand moisture issues, repair options, and the solutions discussed during inspections or estimates. Knowing the terminology makes it easier to make informed decisions about protecting your home.
Air Barrier
A material applied to walls or sheathing to prevent air leakage into or out of a building. Air barriers help reduce drafts, moisture intrusion, and energy loss.
Bowed Wall
A foundation wall that has bent or curved inward due to soil pressure, poor drainage, or structural movement. Bowed walls may indicate serious foundation stress.
Capillary Action
The process by which water is drawn through small pores or cracks in concrete or masonry, even without visible leaks.
Cementitious Waterproofing
A rigid, cement-based coating applied to concrete surfaces to block water penetration. Commonly used on foundation walls.
Cold Joint
A seam where two concrete pours meet. Most commonly referring to the seam between the foundation wall and the footing that is sits on.Cold joints are a common source of basement leaks if not properly sealed.
Crawl Space
A shallow space beneath a home that provides access to plumbing and utilities. Crawl spaces often require vapor barriers or encapsulation to control moisture.
Crack Injection
A repair method where epoxy or polyurethane material is injected into foundation cracks to permanently seal them and stop water intrusion.
Damp Proofing
A basic moisture-resistant coating applied to foundation walls. Damp proofing slows moisture absorption but is not fully waterproof.
Drain Tile (Footing Drain)
A perforated pipe installed around the foundation footing to collect and redirect groundwater away from the structure.
Efflorescence
A white, powdery residue on concrete or masonry caused by moisture carrying minerals to the surface. Often a sign of water intrusion.
Exterior Waterproofing
A comprehensive waterproofing system applied to the outside of foundation walls, typically including a waterproof membrane and drainage system.
Foundation
The structural base of a home that transfers the building’s weight to the ground. Foundations are commonly made of poured concrete, block, or stone.
Foundation Crack
A fracture in a foundation wall or floor caused by settlement, shrinkage, or pressure. Cracks can allow water intrusion if left untreated.
French Drain
A drainage system that uses gravel and perforated pipe to collect and redirect groundwater away from a foundation.
Groundwater
Water that exists in the soil beneath the ground surface. High groundwater levels can place pressure on foundation walls and floors.
Hydrostatic Pressure
The force exerted by standing or moving groundwater against foundation walls or beneath basement floors. A major cause of basement leaks.
Interior Drainage System
A drainage system installed along the interior perimeter of a basement to capture water and direct it to a sump pump.
Mold
A type of fungus that thrives in damp environments. Moist basements and crawl spaces can promote mold growth if not properly waterproofed.
Parge Coat
A thin layer of mortar applied to masonry walls for cosmetic purposes or minor surface protection. Not a waterproof solution on its own.
Polyurethane Injection
A flexible crack repair material that expands when injected, sealing active water leaks and accommodating future movement.
Sump Pump
A mechanical pump installed in a sump basin that removes collected groundwater from a basement and discharges it away from the home.
Vapor Barrier
A plastic or reinforced sheet installed to prevent moisture vapor from entering living spaces. Commonly used in crawl spaces and basements.
Water Table
The level below the ground surface where soil becomes fully saturated with water. A high water table increases basement flooding risk.
Waterproof Membrane
A flexible, rubberized, or liquid-applied coating designed to completely block water from penetrating foundation walls.
Weeping Tile
Another term for drain tile; a perforated pipe system used to collect and move groundwater away from foundations. Commonly 4″ ADS pipe or PVC pipe.