An English basement is the finished lower level of a building, usually in an older urban area, that is partially above and partially below ground level. English basements were originally designed to be rented out as separate apartment units and typically include all the amenities needed for a full apartment. Access to English basements is normally separate from access to the main area of the structure, although an entrance space can be shared, as not all English basements have separate external stairs to street level.
This type of apartment originated in London and was very common during the Victorian era in densely populated urban areas. They can be found in London, New York, Moscow and any other city where living space was scarce. Although they went out of fashion for a while, improvements in basement design technology and rising urban property values have led to their reappearance, and many newer properties in urban population centers will include them.
Several basic architectural problems can be present in an English basement. Since they are located partially below ground level, the level of natural light is generally poorer than in other parts of a dwelling. Like modified basements, they also suffer from the same flooding issues that affect all types of basements. Older versions were notoriously damp and unhealthy, while their modern counterparts are usually acceptably dry, except in cases where drainage or waterproofing systems fail, in which case they can suffer serious damage from flooding.
Owners of semi-detached houses or small apartment buildings with unfinished basements can add substantial additional living space or income potential by transforming the basement spaces of their buildings into English basements. The first phase of this process typically involves upgrading the basement drainage and waterproofing and often requires partitioning the basement as large appliances such as water heaters most often need to remain there and require space and access. Utility services for the building must also be modified if the new English basement is to be rented.
Once the basement space structure has been modified, it can be converted into rental space or, in some cases, sold separately as a condo unit. Building codes may require additional modifications to allow an English basement to be safely inhabited, but modifying a window to serve as a second exit or adding a second external stairway or door entry will satisfy many of these requirements.