In Focus: Class ZA permitted development rights – what rural landowners need to know

In this In Focus article, we explore what Class ZA permitted development is, and the circumstances in which it can and cannot be used
building development

Class ZA permitted development rights are not commonly used by rural landowners and are more often invoked in urban settings. However, there are times when landowners might be able to take advantage of this right to redevelopment redundant buildings.

What is Class ZA permitted development?

Class ZA permitted development is a vehicle that enables landowners in England to demolish disused commercial buildings or flats no longer fit for purpose and replace them with newbuild residential dwellings.

The right is set out in Article 4 of the Town and Country Planning (General Permitted Development) (England) (Amendment) (No.3) Order 2020, which states that to qualify, the building must be either a single purpose-built block of flats or a single detached building within the B1 Class of use. This includes offices, light industrial, and research facilities.

Under this right, the landowner can redevelop either a new single purpose-built block of flats or a new single purpose built dwelling of up to two storeys high on the same footprint.

Class ZA and agricultural buildings

Unfortunately for farmers, what Class ZA permitted development right doesn’t allow is the demolition of old agricultural, forestry, or equestrian buildings and the development of new residential dwellings on the site. Instead, this is covered by Class Q permitted development, which governs the conversation of, but not the demolition or rebuilding of, agricultural buildings into dwellings.

It is for this reason that this class of permitted development is often not relevant to farmers and rural landowners and is used more widely in densely populated areas.

But that doesn’t mean it is completely irrelevant in a rural setting. Some rural business owners do own buildings that are covered by Class ZA permitted development, such as old warehouses, commercial yards, or a block of flats. These may offer potential for residential development once they have reached the end of their working lives.

Constraints of Class ZA

The regulations that govern Class ZA detail a number of constraints that must be adhered to for a building to qualify for permitted development.

First of all, the building to be demolished must have been built on or before 31 December 1989 and must have been vacant for at least six months prior to the submission of the application. A building cannot be demolished in part nor can more than one building be demolished under the same application; the right only applies to a single block of flats or a single commercial building of the B1 Class.

The maximum height of the old building, including radio masts and antennae cannot exceed 18m.

When it comes to the new residential building, the footprint must not exceed 1,000m2. The new building can have as many storeys as the one it replaces had, plus another two, as long as the overall height is not more than 7m higher than the previous building, or more than 18m high overall.

Finally, once the development is completed, the new house or individual flats in the case of a block of flats, cannot be changed into a C4 HMO using Class L, the permitted development right used for changing small dwelling houses into HMOs and vice versa. To achieve this, full planning will be required.

Restrictions on Class ZA use

As well as placing several conditions on the old building and the new development, there are a number of restrictions that govern where Class ZA permitted development can be used.

Class ZA is not permitted in National Parks, Areas of Outstanding Natural Beauty, the Broads, World Heritage Sites or Conservation Areas, and it does not apply in the case of listed buildings or scheduled monuments. It is also not permitted in safety hazard areas, military explosives areas, or within 3km of an aerodrome.

Planning authority considerations

Despite the fact the Class ZA falls under permitted development, there are a lot of aspects of an application planning authorities will take into consideration when presiding over whether or not to approve it. Chief among these are:

  • Land contamination from previous commercial use
  • Flood risk
  • External appearance and design of the new building
  • Natural light in all habitable rooms
  • Impact of noise from surrounding commercial activity
  • Method of demolition
  • Impact on amenity space of the existing building and neighbouring ones

Alongside this, the developer will need to send a construction schedule for the new build which sets out the construction schedule, hours of operation, and how any impacts of noise, dust, vibration, and traffic will be managed and mitigated as is the case for any other type of development.

The plan also needs to include the proposed materials for the new build, plans for disposal and recycling of waste, and how the developer will comply with the plan throughout the duration of the build.

The authority may also request reports on any of the above aspects of the development, or any other aspects they feel will aid them in making a decision about a Class ZA permitted development application.

The planning authority should decide on the application within eight weeks or 56 days of submission but because of all the information required to support an application, this can often take longer.


Class ZA permitted development rights can be a useful tool for decommissioning old blocks of flats or commercial buildings and replacing them with new residential dwellings.

However, to preside over such an application, a local authority is likely to require a large amount of information, meaning a significant upfront cost for landowners or developers regarding the plans, designs, surveys, and reports surrounding the development of the new dwelling.

Whereas this type of permitted development does have some relevance to rural land and business owners, particularly those with vacant warehouses or yards, it is more commonly used in urban environments.

This is particularly the case as it doesn’t govern the conversion of old farm or forestry buildings which are governed by Class Q permitted development, and is probably a more useful tool for farmers and other rural landowners.

If you want advice on Class ZA permitted development, or Class Q, get in touch with our experts.

Key contact:

Andrew Shirley
Andrew Shirley Chief Surveyor, London