Class ZA – Demolition of buildings and construction of new dwellinghouses in their place

Part 20 is a brand new part of the GPDO which came into force in August and September of 2020. References to use classes should be read in the context of the pre September 2020 Use Classes Order and it is anticipated that this will be tidied up in August 2021.

What is allowed

Development consisting of works for the demolition of one or other of—
any building comprising a single purpose-built detached block of flats, and any other single detached building, comprising premises established—
for office use falling within Class B1(a) of the Schedule to the 1987 Order,
for research and development falling within Class B1(b) of the Schedule to the 1987 Order, or
for an industrial process falling within Class B1(c) of the Schedule to the 1987 Order,
or for any combination of them,
existing on 12 March 2020, together with its replacement by a single building.

The building in question is to comprise one or other of—

(a) a purpose-built detached block of flats, or
a purpose-built detached dwellinghouse.

The operations in question are—

• operations reasonably necessary for the demolition and construction, which may include the installation of a basement or cellar in the new building, whether or not there is one in the old building;
• works for the removal of plant servicing the old building;
• works for the disconnection of services from the old building;
• works for the removal of any means of access to and egress from the old building;
• works for the removal of storage and waste from the old building;
• works for the installation of plant to service the new building;
• works for the installation of services to be connected to the new building;
• works to enable access to and egress from the new building, including means of escape from fire;
• works for the construction, within the new building, of storage, waste or other ancillary facilities to support the new building;
• the use of scaffolding and other temporary structures to support the operations listed in paragraphs (a) to (i) over a period—
• starting with their installation no earlier than one month before the beginning of those operations, and ending with their removal no later than one month after the completion of those operations.

Where can I use it

On any existing building in England that was purpose built as a block of flats, offices, research and development or light industrial use and subject to substantive restrictions set out below

What is not allowed

Development is not permitted by Class ZA—if land covered by, or within the curtilage of, the old building—

• is occupied in any part under an agricultural tenancy, unless the express consent of both the landlord and the tenant has been obtained;
• is or forms part of article 2(3) land;
• is or forms part of a site of special scientific interest;
• is or forms part of a listed building or land within its curtilage;
• is or forms part of a scheduled monument or land within its curtilage;
• is or forms part of a safety hazard area;
• is or forms part of a military explosives storage area;
• or is within 3 kilometres of the perimeter of an aerodrome;
• if the old building was constructed after 31 December 1989;
• if the footprint of the old building exceeds 1,000 square metres;
• if the height of the highest part of the roof of the old building above ground level (not including plant, radio masts and antennae) is greater than 18 metres at any point;
• unless the old building has been vacant for a period of at least 6 months immediately prior to the date of the application for prior approval;
• if the old building has been rendered unsafe or otherwise uninhabitable by the action or inaction of any person having an interest in the land on which the old building stands and it is practicable to secure safety or health by works of repair or works for affording temporary support (and for this purpose keeping the old building vacant does not of itself count as action or inaction);
• if the demolition is “relevant demolition” for the purposes of section 196D of the Act (demolition of an unlisted etc building in a conservation area);
• if any of the footprint of the new building falls outside the footprint of the old building
• if any part of the exterior wall of the new building nearest to the highway is nearer than any part nearest to the highway of any exterior wall of the old building
• if the height (not including plant, radio masts and antennae) of the new building would at any point exceed the lower of—
• 7 metres above the height (not including plant) of old building; or
• 18 metres above ground level;
• if the new building has more than X + 2 storeys, where “X” is the number of storeys in the old building;
• if the new building has more storeys than the old building and the floor to ceiling height of any additional storey in the new building, measured internally, would at any point be greater than the lower of—
• the floor to ceiling height, measured internally, of any storey in the old building; or 3 metres; or
• if the height of any plant on the roof of the new building as measured from the lowest surface of that roof would be greater than the height of any existing plant as measured from the lowest surface of the existing roof on the principal part of the old building.

How do I use the allowance

This is a complex prior approval that is tantamount to a full planning application in terms of the depth of assessment and the information submitted. The determining criteria are as follows:

• transport and highways impacts of the development;
• contamination risks in relation to the new building;
• flooding risks in relation to the new building;
• the design of the new building;
• the external appearance of the new building;
• the provision of adequate natural light in all habitable rooms of each new dwellinghouse in or comprising the new building;
• the impact of the development on the amenity of the new building and of neighbouring premises, including overlooking, privacy and light;
• impacts of noise from any commercial premises on the intended occupiers of the new dwellinghouses;
• the impact on business and new residents of the development’s introduction of, or increase in, residential use in the area in which the development is to take place;
• the impact of the development on heritage and archaeology; (k) the method of demolition of the old building;
• the plans for landscaping of the development, including the planting and maintenance of shrubs and trees; and
• any—
• air traffic and defence asset impacts of the development, and
• impact that, because of the siting of the new building, the development will have on a protected vista identified in the Directions Relating to Protected Vistas dated 15 March 2012 by the Secretary of State
• Compliance with National Standards (from 6th April 2021)

Our Notes

Class ZA is at the time of writing untested at appeal and the Government have provided painfully little guidance on its use, function or operation. Applications for Class ZA schemes should not, in our opinion, be undertaken without detailed support from a planning consultant.

The assessment of the “impact on the amenity of any adjoining premises” is not limited to the impact on “overlooking, privacy and the loss of light”. For example, it can include the impact on other aspects of amenity such as “outlook, noise and activity”.

The assessment of the “impact on the amenity of any adjoining premises” is not limited to the impact on properties that “abut, or are contiguous with, the subject property”. For example, it can include the impact on other properties that are “neighbouring premises” (note: these do not have to be “residential premises”).

The assessment of the “external appearance of the dwellinghouse” is not limited to “the design and architectural features of (aa) the principal elevation of the dwellinghouse, and (bb) any side elevation of the dwellinghouse that fronts a highway”. For example, it can include the external appearance of other elevations such as a side elevation that doesn’t front a highway or a rear elevation (note: these do not have to be “public facing elevations”).

The assessment of the “external appearance of the dwellinghouse” is not limited to the impact of that appearance on the “subject property itself”. For example, it can include the impact of that appearance on “neighbouring premises and the locality”.

https://www.bailii.org/ew/cases/EWHC/Admin/2022/208.pdf