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| 3 minutes read


Under new Permitted Development Rights (PDR) announced yesterday, owners of detached blocks of flats will be able to extend their buildings by up to two storeys from August 2020.

The ability to build upwards is a planning issue that has been debated for many years, predominantly focussing on tall buildings – most recently my fellow Partner Chris Miele did so as part of an event with Built Environment Networking Ltd.

However building upwards is not limited to the development of tall buildings. 

Back in 2018, then housing secretary Sajid Javid confirmed that the government supported the principle of building upwards on existing blocks of flats as an additional means of supporting housing delivery.

The subsequent 2019 NPPF signposts the government’s support for such schemes, noting that planning policies should support opportunities to use the airspace above existing residential premises for new homes:

“In particular, they should allow upward extensions where the development would be consistent with the prevailing height and form of neighbouring properties and the overall street scene, is well designed (including complying with any local design policies and standards), and can maintain safe access and egress for occupiers. “

Whilst there is support in the NPPF this has not translated quickly into the delivery of schemes, and in 2019 it was announced that the government were exploring new permitted development rights that provide more freedom for extensions to blocks of flats.

These changes to the regulations were finally laid before Parliament yesterday, 24 June 2020, as part of the Town and Country Planning (Permitted Development and Miscellaneous Amendments) (England) (Coronavirus) Regulations 2020.

Coming in to force on 01 August, the new Part 20 Class A introduces the ability to extend purpose built detached blocks of flats by up to two additional storeys.

As with most permitted development rights, there are certain restrictions and conditions which must be adhered to.  

Detailed assessment of the building and the scheme are of course required, but some of the key considerations include:

Key Consideration

Rights Available?

Detached, purpose built block of flats (not conversions)


Constructed between 01 July 1948 and 05 March 2018


The building is not listed or within a protected area (e.g. conservation area)


The building is not within 3km of an aerodrome


Above ground level, the building is less than 3 storeys in height


The extension is only on the principal part of the building


The extension raises the height of the existing roof by more than 7 metres


The extended building would be greater than 30 metres in height


Whilst these Rights introduce the principle of extending, a Prior Notification process has to be complied with.  

Applications need to cover detail on design matters including external appearance and daylight/sunlight matters which are a new addition to the Prior Notification process.

Personally, I expect that design will be the key matter that needs to be overcome.  Subjective in nature and thus potentially the most difficult matter to resolve, proposals will need to be read as a natural part of the buildings composition and with minimal impact upon the surrounding area, whether or not there are any heritage or viewpoint implications.

It is good to see the requirement for consideration of unit dimensions and natural light as part of the prior notification process.  This requirement has also been extended to office-to-residential conversions, taking steps forward to ensure that all permitted development schemes deliver accommodation of an acceptable quality.

I also envisage that these rights will help drive the move to using more Modern Methods of Construction as this will minimise impact on existing residents and ensure completion within 3 years of permission.  The added advantage of this approach would be the delivery of inherent sustainability benefits and increased build quality.

These changes have come in relatively unannounced despite them being expected for some time.  It is therefore likely that next week’s statement from the Prime Minister will highlight these as an early indication of the government’s plans to deregularise and simplify the planning process to assist with the country’s economic recovery.

More to come, and hopefully as we move forward everything will be on the way up.

Development consisting of works for the construction of up to two additional storeys of new dwellinghouses immediately above the existing topmost residential storey on a building which is a purpose-built, detached block of flats


culture, planning, development, housing, central government, masterplanning, local government, mmc, planning reform, housing delivery, extensions, modern methods of construction, covid-19, heritage, insight