Subterranean Terminology

The lowest storey of a building, usually at least partially above grade, with windows and exterior ventilation.

A traditional term for underground spaces used to store food (as in root cellars) or coal, or a below-grade space with a dirt floor; used regionally as a synonym for basement.

An unfinished space below the first floor that’s less than a full storey in height, normally enclosed by the foundation wall, often for plumbing or mechanical systems.

Encrustations of soluble salts deposited on masonry, usually white and typically caused by alkalies leached from mortar as moisture moves through it.

Popularized by Henry Flagg French in the mid-1800s, a French drain is a trench filled with loose stones containing a perforated pipe that directs surface and ground water away from a structure.

Permeable fabric designed to separate, filter, reinforce, and drain when in contact with soil. Sometimes called an English basement, this is properly the ground floor of a house, used for service and utility areas.

The result of water entering brick, concrete, or stone and forcing the surface to peel, pop out, or flake off.

A pit, tank, or receptacle installed below grade that receives water or waste, and equipped with a pump to empty the water mechanically.