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Permitted Development Rights for Upward Extensions

Picking up from our last update regarding upward extensions back in December 2019, it is now approximately 9 months later and many changes have come into force. Some of this is in response to the pandemic and some to reduce housing shortage.

The permitted development right for upward extensions to residential properties is aimed to provide much needed housing without having to build over green spaces. Similar laws have been introduced for detached blocks of flats and commercial buildings which we will cover separately.

Under the new legislation, homeowners can now extend their properties upwards as follows:

Detached houses:

  • Single storey/bungalows can extend up by 1 storey (max 3.5m tall extension)
  • Two storeys or more can extend up to 2 storeys (max of 7m tall 2 storey extension – the overall height cannot exceed 18m)

Semi-detached houses:

  • No more than 3.5m higher than the property it shares a party wall with.

Terraced properties:

  • No more than 3.5m higher than the highest point of other properties along that terrace.

The property must have been built between 1948 to 2018 and they cannot use this permitted development right to build on top of existing extensions. The house must not be within article 2(3) land eg. a conservation area. Nor can it be within a site of special scientific interest.

As it is a new permitted development right, 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.

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

When does this come into effect?

These changes have been implemented on 31st August 2020.

How will this affect you?

If you own a house that was built between 1948 to 2018, then you could benefit from extending up to two storeys. This would also mean that neighbours can do the same – however as explained above, will be subject to ensuring that the extension is designed appropriately and does not have an adverse impact on neighbouring properties.

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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