The cost of a basement, and its viability for construction as part of any development, will be determined by a number of factors including, most significantly, land value. Previous examples have illustrated how the inclusion of a partial or full basement can increase the potential floor area of a single dwelling and density of whole development, thereby yielding higher returns.

Factors affecting the cost of basement construction include ground conditions such as excavation costs, type of waterproofing system and access for construction.

The TBIC cost analysis provides an elemental breakdown of the range of costs associated with basement construction and summarises the varying influencing factors including type of basement, construction type, plan form and sloping site.

Ground works associated with basement construction can amount to between 18 and 44 per cent of overall construction costs. There is potential scope for cost savings to be made, such as retention of excavated soil on site for landscaping, or adoption of an empty shell specification leading to a reduction in fitting-out costs.

For example see the finished basement cost models