As more people discover this and the cost of space rises ever higher, basement conversion in London has expanded ten-fold since 2001. The borough of Kensington and Chelsea, for example, has seen a rise in planning applications from 46 to 450, and is looking into introducing tighter controls – but the economics will remain compelling for years to come, and councils are bound to welcome well-planned projects that help them attain their housing and development targets.

The Compelling Economics of Basement Conversions

Although the addition of basement floors beneath existing buildings can be significantly higher than a typical loft conversion, this is not always the case when ceiling heights and access are already adequate. Even when major excavations, underpinning and drainage solutions are required, the cost per square metre of new space will still be less than the market price per square metre of existing space in areas of high property values. Therefore the creation of lower floors is the most profitable option even before the additional costs and disruption of moving are factored in.

An estate agent can quickly provide you with an estimate of the market value of space in your area and help you calculate your gains and savings from the project.

More Space Extension Opportunities

Another key advantage compared to adding floors at the top of a building is that the extra space may be considerably greater. No top floor can be larger than the floor beneath it (at least, not under post-Elizabethan building regulations) and planning rules are almost certain to set maximum heights by which a building can be raised. A basement level build can extend not only beneath the house but beneath a garden, drive or car-parking area too.

Roof spaces tend to lend themselves to use as bedrooms rather than anything else – not least because access will have to be through existing living space – but basement spaces typically have a wider range of uses as bars, gyms, home theatres, recording studios, or if there is sufficient natural light as entire new apartment or office space. This versatility opens up your creative horizons – a new basement level creates an opportunity for innovative design, elegant light wells and atria and open spaces, saunas or even a pool.

Planning and Building Regulation

Although restraints on multiple sub-floor projects will likely be tightened, for the foreseeable future basement conversion in London, as in most other parts of the country, will continue to encounter fewer planning permission obstacles than comparable alterations to upper floors, because the addition is often invisible from the street. Where cellars already exist, planning permission is often not required at all.

However, basement levels present such a range of potential problems and opportunities that specialist building companies have sprung up to meet the new market. They have the expertise to guide you through the design, planning and project management phases of this exciting new vogue of development in our capital city, and ensure your new space benefits from the latest environmentally friendly and energy efficient innovations.