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Permitted Development Rights for Upward Extensions to Blocks of Flats

Following our previous update regarding new permitted development rights to extending houses, there is also the option to extend blocks of flats without planning permission. The permitted development rights for flats means that owners have the option to carry out upward extensions

This new permitted development right for flats which allows owners of a block of flats to create new dwellings on top through a 2 storey upward extension, is aimed to ease the housing crisis and recover from the economic impact from the pandemic without having to build over green space such as the countryside. This would also help further maximise the use of existing land and buildings in its airspace which is also in line with the National Planning.

Policy Framework (NPPF).

Under the new legislation, existing blocks of flats can extend upwards as follows:

The existing building must be;

– A purpose-built detached block of flats (not a conversion)

– Built between 1st July 1948 to 5th March 2018

– At least 3 storeys as existing

– No taller than 30m once extended (not including plant)

The upward extension must;

– Have internal floor to ceiling heights of each storey not exceeding 3m

– Be a maximum of 2 storeys

– Not exceed 7m above the existing building (not including height created by plant)

The block of flats must not be within article 2(3) land eg. a conservation area. Nor can it be within a site of special scientific interest. The extension can only be added to the top of the “principal part of the existing building” which means you cannot extend a lower part of the property eg. if the flats consist of a tower and a podium/base – the extension cannot be added on the roof of the podium. It is also important to remember that Local Authorities could impose an Article 4 direction onto specific areas to prevent the implementation of this new PD right. Therefore, it is good to investigate whether your property has an Article 4 direction attached.

Whilst is a permitted development right for flats, these extensions will still need Prior Approval from the Local Authority and as such planning officers will have to assess the proposal by making sure that it does not adversely impact neighbouring properties such as through loss of light/overshadowing, privacy and overlooking. The extension would also have to consider its impacts on the existing dwellings inside the building itself.

Similarly to other Prior Approval submissions, Local Authorities need to access its effects on the following:

– Highways

– Contamination

– Floor Risk

– Noise

– Air traffic and defence asset impacts

– External appearance

– Access to adequate natural light

– Protected views

Occupants of the property and adjoining neighbours will have to be notified and consulted of this Prior Approval and as such are given the opportunity to comment on the proposed works.

People have always been able to apply to extend blocks of flats upwards but through the longer and more expensive process of a Full Planning Application. Prior Approval cuts a lot of red tapes but the extension can’t be given the go-ahead unless the Local Authority are satisfied it will not harm neighbouring homes.

Other permitted works to facilitate these upward extensions:

The legislation allows for reasonable engineering works that required to achieve adequate structural stability to accommodate the additional floors. Works to replace existing or for the installation of new plant is permitted to facilitate the extension as well as provisions for appropriate and safe means of escape which could include additional external doors and staircases.

When does this come into effect?

The permitted development rights for flats changes have been implemented on 31st August 2020.

How will this affect you?

If you own a detached purpose built block of flats that was built between 1948 to 2018, then you could benefit from extending up to two storeys, bearing in mind – as explained above this will be subject to ensuring that the extension is designed appropriately and does not have an adverse impact on neighbouring properties and occupants of the existing building.

How can we help?

We have an expansive portfolio of extending properties both under permitted development and full planning applications – we can assist you in finding the best solution financially and in terms of design. We can help achieve this through feasibility studies and eventually through the submission of a Prior Approval application. Please contact us at or call at 0208 944 1180.

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