Class ZA - Demolishing office buildings to unlock new homes

Introduced in 2020, Class ZA permitted development rights allow the demolition of commercial premises and residential properties to create new homes, helping to increase housing supply by redeveloping vacant buildings.

September 27, 2023

As working habits have changed and more people have the opportunity to work from home, businesses need less office space to accommodate employees. According to research by Costar, a property insights provider, empty office space across the UK surpasses 100 million sq ft. 

Class ZA - reimagining commercial spaces

For developers looking to capitalise on the land opportunities of vacant commercial buildings (or blocks of flats), Class ZA provides permitted development rights to demolish existing buildings and replace them with new homes.

And with vacant space in London up by 50% since 2019, the opportunity for development in some of the UK’s most lucrative residential markets is clear.

What qualifies under permitted development rights?

Class ZA permits the demolition of either a standalone block of flats or a single detached building falling under B1 Use Class, as long as they existed on 12th March 2020. With this permission, you can replace it with a new block of flats or a standalone house with an extra two storeys in the airspace.

In terms of sites, we’re looking at offices B1(a), Research and Development B1(b), Industrial Processes B1(c), and dwellings like flats.

As usual, there are some specific space and height requirements for the types of buildings that meet the criteria. Most importantly, the footprint of the existing building can be no larger than 1000 sqm and the highest part of the existing building cannot be taller than 18m.

How big can you go?

When planning your new building, there are a couple of key things to remember. First off, the base area of the new building can't be larger than the original one (so 1000 sqm would be the maximum size site possible).

And second, height limits – the new structure can’t be taller than 18m, or extend more than 7m above the height of the building it's replacing. Interestingly, you can add a basement to the building whether it had one previously or not! 

Class ZA opportunities shown on a laptop screen

Everything you need to consider with Class ZA opportunities

  • The building should have been constructed no later than 31st December 1989
  • It should have been vacant for a minimum of 6 months
  • The existing building’s footprint must be 1,000 sqm or less
  • Demolition is only allowed for a whole building, not part of it, and only one building can be demolished
  • The replacement building can include as many storeys as the original, plus two additional ones in the airspace, provided the height doesn’t exceed an extra 7m or 18m in total
  • Once complete you cannot change the single house or any of the flats in the block to C4 HMO unless full planning is obtained
  • You cannot use this permitted development right of in Article 2(3) land, conservation areas, SSSIs, listed buildings, scheduled monuments, safety hazard areas, military explosives areas or within 3 kilometres of an aerodrome

How to source Class ZA land opportunities

Unless you possess eyes and ears in every town and city across the UK and understand the history and background of every potential site, identifying Class ZA opportunities quickly can prove challenging.

However, for Searchland users, discovering these sites is straightforward. By applying the correct array of filters to our land-sourcing search tool, you can swiftly assemble all the suitable Class ZA sites within your chosen area, providing you with all the information necessary to sift through opportunities at scale. And if you need a hand working out the right mix of filters, our team can help!

To get started,  jump on a demo with our onboarding team so they can show you our full set of features.

July 9, 2024

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