Use of basements in enhancing existing houses in urban areas:

In general, domestic basements can aid in the creation of desirable, sustainable homes, providing greater flexibility and adaptability of space; thus extending the design life of the building. Basements provide useful and functional amenities to the occupants in the form of gyms, recreational areas, underground car parking and other facilities.

The benefits of adding basements to existing houses is to provide comfortable day-lit rooms, with natural ventilation and external access, as an extension to the living spaces above, but also provide the opportunity for more unique uses such as gyms, music rooms and work places.
Good acoustic attenuation is provided by the concrete walls surrounding basement rooms, by the earth itself and significantly by the ground floor constructed in concrete. Basement spaces are therefore inherently ideal location for noisy activities or to provide quiet spaces separated from the rest of the home, such as cinemas, music rooms, gyms and home offices.

Subterranean spaces benefit from the insulating properties of the surrounding ground, improving their energy efficiency. As a consequence, the amount of insulation needed to reduce heat loss through a basement wall is less than that required on upper floor levels. Studies by The Basement Information Centre (TBIC) and BRE highlight a potential 10 per cent saving in space heating for a two-storey house with a full ground basement compared with its three-story equivalent above ground (both having the same amount of added insulation). The potential space heating saving rises to around 14 per cent for a single storey property with full basement, compared to its two-storey equivalent above ground.

The heavyweight nature of basement construction can be utilised to naturally regulate the internal temperature of a home and can be part of an energy efficiency strategy for controlling the temperature of the whole house. The thermal mass properties of concrete are optimised by omitting insulating internal surface finishes. If insulated and waterproofed externally, basement concrete walls will offer greater thermal mass. This could be achieved with a fair-faced or painted finish, or alternatively a wet plaster finish.

The construction of sustainable dwellings using low air permeability and mechanical ventilation with heat recovery, such as Passiv Haus technique, is a means of improving the energy efficiency of the building fabric of dwellings. This is simply provided by basements, since the structure below ground is inherently more air tight.

Many of the fundamental principles of sustainable design can be addressed through the provision of a domestic basement, including energy efficiency, longevity and adaptability of the property and support of local employment through home working potential. Additional space can be provided for the storage of waste for recycling, alternative fuel supplies or other equipment associated with renewable energy or water recycling. In addition basements can provide additional floor space without increasing the building footprint or significantly reducing garden size.