A basement floor is a partially underground storey of a building, where the top of the floor is below ground level but the space partly projects above ground. This allows a basement floor to receive daylight through windows in the facade, unlike a fully underground cellar.
Difference between basement floor, cellar and basement
| Basement floor | Cellar | Basement | |
|---|---|---|---|
| Position | Partly below, partly above ground level | Entirely below ground level | English term for basement floor/cellar |
| Daylight | Yes, via facade windows | No or minimal | Varies |
| Habitable | Often yes (provided there is sufficient light and ventilation) | Usually not | Varies |
| Access | Own door or external staircase | Internal staircase | Varies |
Applications
- Living space: bedroom, study, television room
- Practice room: office, studio, home practice
- Storage: storage space with good accessibility
- Letting: self-contained dwelling unit (check the local plan)
Points of attention for the DIYer
- Damp-proofing: waterproof basement walls and floor are essential
- Ventilation: ensure sufficient air renewal (mechanical or natural)
- Light entry: light wells or light shafts increase daylight penetration
- Building Regulations: minimum ceiling height of 2.30 m for a habitable room
- Planning permission: check the local plan for use as living accommodation
- Drainage: around the foundation to discharge groundwater
Waterproofing a basement floor
- External: waterproof coating or membrane on the basement wall
- Internal: waterproof render or cementitious coating
- Floor: waterproof concrete floor with a chine strip at the junction with the wall
- Drainage: perimeter drain connected to a sump pump
Related terms
- Cellar: fully underground space
- Light well: light shaft at a basement window
- Crawl space: low, non-habitable space below the ground floor
- Ground level: the ground surface around a building