Basement Applications

Planning applications for householder basements are becoming more common.

If you receive notification that your neighbour has submitted a basement application this section will give you information about what to expect and what to look out for.

Objecting to a Basement Application

If the London Borough of Barnet (LBB) serves a notice on you that a planning application has been made involving a basement affecting your property, somewhere on the letter there will be a planning reference number and a date by when any objection has to be received. You need to reply to the planning officer by the due date, giving the planning reference number and including your own name and address. You can do this by letter, email or on the Council’s own planning portal. As you are commenting on something the Council has asked you about your view will be important. Copying your objection to your local councillor(s) may help. (Further details are available on our ‘Objecting to a Planning Application’ page on this website.)

The Structural Engineer on our Committee has set out the following comments, and these relate mostly to single level basements predominantly under domestic dwellings:
Where properties are being developed close to other houses there are many issues, noise, traffic, overlooking, disruption and in some cases structural damage to neighbours’ buildings. Significant engineering works, even when ‘invisible’ under domestic buildings, are required to have Planning Permission as well as Building Control Approval. Where buildings are close, the onus is on the owner of the building being developed to take due care of the neighbouring building(s). All this work is covered by an Act of Parliament, The Party Wall etc. Act 1996.

The Act is complicated and specialist surveyors, called Party Wall Surveyors, usually deal with these matters. All fees (in normal circumstances) are paid for by the owner of the property being developed. Any work to the Party Wall and generally any excavations within 3m of a neighbouring property are covered by the Act, but not generally trees along a boundary.

Beware the neighbour who invites you round for a quick drink to explain his/her proposed new basement scheme! To fully understand the proposals it is important to see proper drawings showing the relationship between the new proposals, neighbouring properties, and the permanent and temporary work that will be undertaken. That information should be submitted with the Planning Application. If you are a member of the Society and need a view on this subject then please send any drawings or other information to MHPS, The Studio, Nan Clark’s lane, Mill Hill, NW7 5HH and we may be able to help you decide a suitable course of action. (email

Sources of information:
Barnet’s Draft Local Plan, January 2020 covers Basements
Policy CDH06 Basements
Proposals for basements should follow good design principles in accordance with the Residential Design Guidance and Sustainable Design and Construction (Supplementary Planning Documents – SPDs). Basement proposals to properties should:
a) Ensure that tree roots on or adjoining the site are not damaged.
b) Ensure that not more than 50% of the amenity space (garden or front court yard) is removed.
c) Have no demonstrable adverse impact on neighbouring ground water conditions.
d) Be subordinate to the property being extended and respect its original design, character and proportions for any visible aspects of the extension.
e) Ensure railings, grilles and other light-well treatments avoid creating visual clutter and detracting from an existing frontage or boundary wall, or obscuring front windows.
f) Be able to function properly for the purpose intended, with rooms of an adequate size and shape receiving natural lighting and ventilation. All habitable rooms within basement accommodation should have minimum headroom of 2.5 metres.
g) Consider impact of forecourt parking on light to basement windows.

The London Borough of Richmond upon Thames uses a Planning Advice Note called ‘Good Practice Guide on Basement Developments’ published in May 2015 and, written in clear non-jargon English, explains the issues and where to go for advice.
Check out

The Internet: Further information can be found by putting ‘Digging down in the basics of basements’ into Google where you should find an article written by John Wevill of Boodle Hatfield, Solicitors. In this article is a note about the Party Wall etc Act 1996 which is applicable alongside the Building Regulations.

Mill Hill Preservation Society