As Islington and Camden councils deal with rising planning applications for basement developments, experts have pointed out the drawbacks of venturing underground

Planning applications to dig basements in London have soared in the past year as housing prices reach ever-higher proportions. Yet the cost and duration of subterranean developments mean the extensions are putting a strain on the local community.

Speaking to the Financial Times, Oliver Froment, chairman of the Camden Residents Association Action Committee, said: “Having a basement built next to your house is very noisy, it’s like drilling a tunnel next to you. It’s a complex engineering process, constant piling, your house shakes.”

Due to soaring property values in the borough, Islington’s number of applications to excavate large basement developments has been steadily on the rise, having increased from 41 to 62 between 2013 and 2014.

Froment added that some developers were known to buy houses, adding basements to bump up the price and selling them on. “That’s the sort of thing that’s wrong. It’s different if someone lives in a house and needs more space.”

Indeed, for many the spiralling costs of moving house mean expansion is the only option rather than a vision of grandeur, and London homeowners are increasingly choosing to improve their home rather than moving to a larger property.

Renovation comes with its own set of challenges, however, as households are trying to squeeze in extensions, resulting in awkward or dark spaces.

While creating extra space may be tempting, the value of investing in a basement extension is debatable, and north London architects have pointed out that the steep price of doing building works in London can surmount the price of moving house.

With a law that is open to interpretation, many boroughs don’t require planning permission for basement extensions - but the stark rise in applications prompted councils to step in.

In January 2016, Islington became the third borough to implement additional restrictions on basement construction, joining Kensington & Chelsea and Westminster.

The Islington council launched a consultation in 2014, due to growing concerns about the rapid increase in planning applications for major basement developments. The final Supplementary Planning Document (SPD) was approved early this year.

The SPD asserts that all basement development should be appropriate and proportionate to its site and context. Basement developments are also limited from being more than double the ‘footprint’ of the original building or from taking up 50 per cent or more of the garden.

It is the neighbours who often suffer the most when it comes to these extravagant development projects. The work on basement excavations is so invasive and long that homeowners usually have to move out, typically for about a year. But the neighbourhood is left to endure months of noise, drilling and traffic congestion.

Disruptive construction works have been the source of countless neighbourhood brawls in the area. A Camden petition passed 11,000 signatures in January, protesting plans to build a luxurious basement with swimming pool, gym, sauna and cinema. The noise and vibrations of the building works could lead to the forced closure of the historic AIR studios.

In Hampstead, residents are calling for applicants to prove the works will have no structural effects on neighbouring properties, even arguing the neighbours should be financially compensated for the trouble.