Is this the death of the basement extension?

New basement extension restrictions limit potential upgrades

The Royal Borough of Kensington & Chelsea has this week implemented its planned strict guidelines for the addition of new basements to houses within its authority.

Basement extensions were traditionally a way to extend a traditional home within the strict borough without damaging the external appearance of the conservation area. The new underground areas could house anything from new bedrooms, spas, gyms, pools or underground parking and could add massive additional capital to these already expensive homes.

But neighbours and other residents of Kensington & Chelsea were constantly under siege from diggers, construction traffic, dust and noise.

Under the new guidelines, the maximum extent a basement can be extended under a property’s garden has reduced from 85 percent to 50 percent. It restricts basements to single storeys and bans any basement under a listed building.

Over 450 applications for basement extensions were put on hold last month whilst the new guidelines were reviewed. Now that the ruling has been passed these planning applications will be released and processed but it is thought that very few will comply with the new strict measures.

Although the construction of a basement extension is one of the most expensive ways to extend a property the monetary payback on the value of a home in London is more than an incentive for the wealthy homeowners to extend downwards.  

The traditional terraces houses that populate the Royal Borough have allowed the area to be described as a ‘Victorian Citadel’ and planning restraints within the area are notoriously difficult. This new restriction on building within Kensington and Chelsea has not been well received by architects and designers who already had a difficult relationship with "the borough that likes to say no".