RBKC policies on basements

The number of planning applications for basement excavations in Kensington and Chelsea has been increasing almost exponentially over the last decade or so. In 2001, there were 46 applications; 192 in 2007; and 450 in 2013. During this period, Council policy has evolved considerably.

When basement development first became popular and the problems that the excavations caused for neighbours became obvious, the Planning Committee tried to refuse applications on grounds of over-development and similar. But when the applicants appealed to a Government Inspector, the refusals were overturned and it became obvious that Government policy meant that applications for new basements had to be accepted in the vast majority of cases. This is still the case today and very few applications have been successfully refused. The argument is that, although these developments can cause two or three years of hell for neighbours, once they have been built they are invisible and therefore have no impact on the neighbourhood. Most of the applications that have been successfully refused are ones where there were objectional external features such as light-wells.

The Council has, however, developed a number of policies that have placed restrictions on basement development. They have also imposed a number of quite onerous requirements for documentation that has to be produced before planning permission can be granted. The current policies are now mainly set out in the following documents:

The Local Plan (formerly the Core Strategy), as amended by the new policy on basements adopted in January 2015. This (the new policy) is the basic policy document. In particular, it bans double basements in most circumstances and restricts the construction of basements under the garden to no more than 50% of the garden area (it was 85% before).

Supplementary Planning Document (SPD) on Basements , issued in 2016.. Its aim is to give further guidance on the basic policy, so it is an important document. It replaced an earlier SPD issued in 2009.

Local Validation List setting out the information that must be submitted with planning applications. More details

Construction Traffic Management Plan (CTMP) pro-forma. Applicants for basement developments must submit with their application a draft CTMP seting out how the construction traffic will be managed so as to minimise problems for the neighbourhood. The CTMP Pro-Forma sets out the information that must be provided. It has recently been expanded and improved, and includes a certain amount of guidance on what is and is not acceptable. The Council has over the past year been extremely active in taking action against any breaches of an agreed CTMP.

Until April 2016, basementsentirely “under the footprint of the house” could be built without planning permission. After considerable pressure from the Ladbroke Association and others, the Council made an "Article 4 direction" applying throughout the borough to require these basements to have planning permission. After a period of consultation, the Article 4 direction was confirmed on 15 April 2016 and comes into effect on 28 April 2015. So from now on all basements will require planning permission, which is excellent news as basements under the house will be subject to the same safeguards and requirements (e.g. on Construction Traffic Management Plans) as basements extending beyond the house. Any basement construction started before 28 April 2016, however, can go ahead under the old rules.

Also in April 2016, the Council issued a Code of Construction Practice on noise, vibration and dust.. This applies to all building developments, but is particularly relevant to basement projects given the noise and vibration problems associated with them. Not all of the provisions in the code can be enforced by the Council, but many can, so if you are unlucky enough to be living next to a basement excavation, it is well worth your familiarising yourself with it so that you take up any breaches with the Council.

There is also a page on the Council website called "Advice to builders" which contains quite a lot of useful material on how projects should be managed to minimise environmental impacts - see:

www.rbkc.gov.uk/environment/advice-builders. This covers inter alia advice to builders working on the highway; how to avoid and resolve noise problems and other annoyance on site; protecting trees during building works; ensuring good communication with neighbours; dealing with drainage and flooding problems during construction work; and avoiding light pollution during construction work. Again, those living next to a basement excavation may find it useful to familiarise themselves with the advice so that they can point it out to contractors who appear not to be abiding by it.

In order to inform its policy on basements, the Council commissioned two reports from internationally respected firms of civil engineers, one published in 2008 and one in 2013. Although these are now quite old, they - and in particular the second - contain much useful technical information. They are:

Ove Arup Report of June 2008, which fed into the drafting of the original SPD on subterranean development. This found that there should be no problems with basement developments provided that they are designed and undertaken by experienced and competent teams. This is a very if; although no systematic engineering study has been done of those cases where serious problems have arisen, it does seem that most were caused either by bad design or by bad workmanship.

Alan Baxter and Associates Report of March 2013, a more thorough publication that sets out in some detail the problems that can arise from basement excavation. It is in exceptionally clear language for a technical report and well worth looking at. This helped in the development of the new more restrictive policy.

When the Council grants planning permission for a basement developments, it normally makes the planning permission subject to various conditions, and also includes a number of “informatives” – advice on other requirements that applicants will need to meet. More information on conditions and informatives.

Back to main Basements page .

This page was last updated on 27 April 2016.