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Spreading roots - current issues surrounding planning requirements for basement extensions

This article was first published in Building Products and the full article can be found online here.

As property prices escalate, particularly in London, more people are considering extending their properties underground to increase floor space and create a more comfortable living environment.

This recent trend has resulted in an increase in basement excavations and extensions and some of these basement extensions are extravagant, with underground swimming pools being built, as well as spas, gyms and home cinemas.

As many basement extensions can be carried out without obtaining formal planning permission, they are not subject to the usual controls that the planning system can offer.

This not only means that it is difficult for local authorities to determine or control the number of basement extensions being carried out in a local area but it has also led to many disgruntled neighbours who have had to endure prolonged construction phases (sometimes over a year) together with increased noise, pollution and traffic which arise when construction works are being carried out.

In response, and in an attempt to regain some control, local authorities have sought to implement restrictions to limit the size and depth of permitted excavations. Before looking at these restrictions it’s important to understand when planning permission is required.

Planning requirements
In general, planning permission is required for any development on land. The term development is defined in the Town and Country Planning Act 1990 (TCPA) as: "The carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land."

Whilst constructing a basement extension would constitute a development for the purposes of TCPA, a recent High Court case has established that certain basement extensions can be undertaken without requiring formal planning permission by utilising permitted development rights for dwellings which can be found in Part 1 of Schedule 2 to the Town and Country Planning (General Permitted Development) Order 2015 (GPDO). Essentially, this applies if the proposed basement is no deeper than one storey and it complies with certain requirements as to its ‘footprint’.

This means that no planning application is required for proposed basement extensions which fall within the limits of Schedule 2, and subject to meeting any building control requirements, a property owner can in theory immediately commence works on such a basement extension without any recourse to their local authority.

Lawful use certificates
Whilst a proposed basement extension may fall within Schedule 2 and benefit from permitted development rights so that planning permission is not required, naturally when homeowners are spending considerable sums of money (or borrowing considerable sums) they will want some assurance that the proposed works are indeed permitted. In these circumstances, the homeowner can make an application under the TCPA for what is known as a certificate of lawfulness of proposed development, also known as a ‘CLOPUD’. Their application need simply set out how the proposed basement complies with the Schedule and the local authority has no choice but to grant the certificate. Once such a certificate is obtained, it confirms the development as lawful and means the homeowner is protected from enforcement action.

These certificates can be particularly useful given that there are a number of exceptions to permitted development rights:

  • land which falls within a conservation area is subject to more restrictive planning controls.
  • listed buildings have no permitted development rights.
  • the rights do not apply to a proposed basement extension for a flat or a maisonette, or if once the extension is complete, what has been created is a separate living unit.

Localism in action
Under Article 4 of the GPDO, a local authority is able to make a direction to remove these permitted development rights from all or part of their area. These directions will normally need confirmation from the Minister. If permitted development rights are removed under Article 4, the outcome is not to prevent basement development altogether, but instead those wishing to construct a basement extension will be required to make a full planning application. However, this process is not without consequence as the local authority can be required to pay compensation if it refuses planning permission for a development which would otherwise have been permitted development, less than 12 months’ after notice of the direction was first given.

In response to the growing number of basements, Karen Buck, MP for Westminster North, is promoting a private members bill, The Basement Excavation (Restriction of Permitted Development) Bill 2015-16. Few details have yet emerged about the bill which, if enacted, could mark a significant shake up for basement extensions and planning.

The bill is being promoted on the basis that local authorities should not need to go "cap in hand to the Secretary of State" to obtain Article 4 powers. The bill was summarised as "to restrict the application of permitted development rights; to grant local planning authorities powers to restrict the size and depth of basement excavations underneath or adjacent to residential properties; and for connected purposes".

If the proposed Bill has legs, the days of constructing elaborate basement extensions under permitted development rights may soon come to an end and instead homeowners will be subject to making a full planning application.

In the meantime, those planning basement extensions should be also be aware that if a certificate (CLOPUD) is granted, but permitted development rights are removed under Article 4 prior to commencement of the development, the certificate will no longer be valid – although compensation may be available.