Richmond: the Latest Borough to Restrict Basement Builds

The limited options for expansion in London properties caused a surge in popularity for basement extensions as homeowners dug down to find more space. In reaction, concern spread about the safety and long term consequences of such builds, and across the capital borough after borough have formally restricted basement developments with new, stricter guidelines that are especially punishing for multi-level basements.

At DGA, we’re big believers in basements and have successfully seen multi-level extensions through to completion in London’s toughest boroughs. Much of what’s being made mandatory is already common practice for us but the bans on mutli-level basements is disappointing as I’ve seen first hand how much they can add to a home without taking anything away from the surrounding area.

Unfortunately, news on tougher basement policy has become a regular feature on the blog. Just last month I detailed Wandsworth’s new basement SPD which was preceded by a post in December when RBKC left 120 applications on the cutting room floor. If you’ve been keeping up with the falling dominoes, then you have a good idea of what to expect from Richmond.

The borough published a new Good Practice Guide on Basement Developments, which covers what’s required of a developer along with advice for neighbours affected by a build – and expectations have risen across the board. Richmond has historically been a borough with widespread basement developments, so the changes here will be particularly impactful.

As in Wandsworth, Richmond now demands a Construction Method Statement for all basement applications, significantly increasing the cost of submitting a planning application. A CMS is a collection of documents displaying that the build will follow guidance from various accredited surveyors and consultants, covering everything from vehicles and parking to recycling and waste.

Following the precedent set by other boroughs, basement extensions cannot extend more than 50% beneath the garden and the only visual features permitted are lightwells and skylights. The soil layer above the basement must also be thick enough to support garden planting and drainage.

The limits on scale are largely due to concerns over land stability, groundwater impact and flood risk – all elements that will have to be considered in a planning application for a basement development. Richmond’s proximity to the Thames and abundance of clay soil means planning departments will be especially strict when it comes to any potential flood risk.

As for multi-level basements, while the Wandsworth basement SPD explicitly stated that multi-level basements “are not considered appropriate” in the borough, there’s no such mention in Richmond’s Good Practice Guide.

But I don’t think no news is good news. Their planning review is informed and inspired by measures taken in Camden, Hammersmith & Fulham, RBKC and Westminster, where basement extensions were strictly limited to one storey.

What we do find is a warning against over-development, stating:

“Just as overly large extensions above ground level can dominate a building and contribute to the over-development of a site, an extension below ground can also be of an inappropriate scale.”

Taking the history of London basement policy and the above warning into account, it’s safe to assume that multi-level basements will be incredibly difficult if not impossible to have approved in Richmond. As in Wandsworth, I’m still curious to see whether exceptions will be possible given our track record for successful and safe multi-level basements.

It’s clear which way the wind is blowing, and I expect we’ll see many more boroughs update their basement guidelines with similarly strict revisions. As the costs and risk increases for homeowners, it’s essential you consult with architects who have expansive portfolios in basement developments and an excellent planning approval rating. I’m proud to say DGA has both, so feel free to get in touch if you’re planning to expand your home.

Click here to read the full Good Practice Guide on Basement Developments.

John Dyer-Grimes