Upwards extensions to homes

Following the June 2020 announcement that purpose-built blocks of flats will be able to extend upwards without applying for planning permission (insert link to News flash: Permitted Development Rights allowing two-storey upwards extensions June 25, 2020) the government published a new round of new permitted development rights set out in The Town and Country Planning (General Permitted Development) (England) (Amendment) (No. 2) Order 2020. 

The first of those permitted rights potentially allows households to extend their houses by adding additional storeys to their homes via Prior Approval. 

The government first announced its intention to allow upwards extensions back in March 2019. This announcement was part of the government’s plan to reform Planning and Permitted Development in depth See our blog post discussing these changes.

The new legislation for the creation of this new permitted development right was finally published 21st July 2020.

Under the new Class AA, households will be able to add up to 2 storeys to their houses (limited to 1 additional floor for bungalows).

The government are trailblazing it as great news for families who need additional living space in their homes, although there are a number of conditions restricting the use of this right. Most notably it can’t be any of the following:

  • within a Conservation Area
  • the house must can’t have been built before July 1948 or after 28th October 2018.
  • the extended floors must be no higher than 18m
  • more than one additional storey for bungalows, semi-detached houses and terraced houses.

The new PD right is not automatic and requires a chargeable application to the relevant Local Planning Authority. Any application must include the submission of a Construction Management Plan. 

The new regulation which will come into force 31st August 2020 and is written as below:

Class AA - enlargement of a dwellinghouse by construction of additional storeys

AA.  The enlargement of a dwellinghouse consisting of the construction of—

(a) up to two additional storeys, where the existing dwellinghouse consists of two or more storeys; or

(b) one additional storey, where the existing dwellinghouse consists of one storey, immediately above the topmost storey of the dwellinghouse, together with any engineering operations reasonably necessary for the purpose of that construction.

Development not permitted

AA.1.  Development is not permitted by Class AA if—

(a) permission to use the dwellinghouse as a dwellinghouse has been granted only by virtue of Class M, N, O, P, PA or Q of Part 3 of this Schedule (changes of use);

(b) the dwellinghouse is located on—

(i) article 2(3) land; or

(ii) a site of special scientific interest;

(c) the dwellinghouse was constructed before 1st July 1948 or after 28th October 2018;

(d) the existing dwellinghouse has been enlarged by the addition of one or more storeys above the original dwellinghouse, whether in reliance on the permission granted by Class AA or otherwise;

(e) following the development the height of the highest part of the roof of the dwellinghouse would exceed 18 metres;

(f) following the development the height of the highest part of the roof of the dwellinghouse would exceed the height of the highest part of the roof of the existing dwellinghouse by more than—

(i) 3.5 metres, where the existing dwellinghouse consists of one storey; or

(ii) 7 metres, where the existing dwellinghouse consists of more than one storey;

(g) the dwellinghouse is not detached and following the development the height of the highest part of its roof would exceed by more than 3.5 metres—

(i) in the case of a semi-detached house, the height of the highest part of the roof of the building with which it shares a party wall (or, as the case may be, which has a main wall adjoining its main wall); or

(ii) in the case of a terrace house, the height of the highest part of the roof of every other building in the row in which it is situated;

(h) the floor to ceiling height of any additional storey, measured internally, would exceed the lower of—

(i) 3 metres; or

(ii) the floor to ceiling height, measured internally, of any storey of the principal part of the existing dwellinghouse;

(i) any additional storey is constructed other than on the principal part of the dwellinghouse;

(j) the development would include the provision of visible support structures on or attached to the exterior of the dwellinghouse upon completion of the development; or

(k) the development would include any engineering operations other than works within the curtilage of the dwellinghouse to strengthen its existing walls or existing foundations.


AA.2.—(1) Development is permitted by Class AA subject to the conditions set out in sub-paragraphs (2) and (3).

(2) The conditions in this sub-paragraph are as follows—

(a) the materials used in any exterior work must be of a similar appearance to those used in the construction of the exterior of the existing dwellinghouse;

(b) the development must not include a window in any wall or roof slope forming a side elevation of the dwelling house;

(c) the roof pitch of the principal part of the dwellinghouse following the development must be the same as the roof pitch of the existing dwellinghouse; and

(d) following the development, the dwellinghouse must be used as a dwellinghouse within the meaning of Class C3 of the Schedule to the Use Classes Order and for no other purpose, except to the extent that the other purpose is ancillary to the primary use as a dwellinghouse.

(3) The conditions in this sub-paragraph are as follows—

(a) before beginning the development, the developer must apply to the local planning authority for prior approval as to—

(i) impact on the amenity of any adjoining premises including overlooking, privacy and the loss of light;

(ii) the external appearance of the dwellinghouse, including 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;

(iii) air traffic and defence asset impacts of the development; and

(iv)whether, as a result of the siting of the dwellinghouse, the development will impact on a protected view identified in the Directions Relating to Protected Vistas dated 15th March 2012(1) issued by the Secretary of State;

(b) before beginning the development, the developer must provide the local planning authority with a report for the management of the construction of the development, which sets out the proposed development hours of operation and how any adverse impact of noise, dust, vibration and traffic on adjoining owners or occupiers will be mitigated;

(c) the development must be completed within a period of 3 years starting with the date prior approval is granted;

(d) the developer must notify the local planning authority of the completion of the development as soon as reasonably practicable after completion; and

(e) that notification must be in writing and include—

(i) the name of the developer;

(ii) the address of the dwellinghouse; and

(iii) the date of completion.

Ask Us

Despite the triumphal announcement, there are many limitations to this PD right. Many of our clients live in areas where the majority of housing stock was built pre 1948 when much of the nation’s housing stock was erected. Buildings built towards the latter end of the permitted time range will often have restrictive conditions preventing permitted development rights. These conditions may be open to challenge.  

If you do possess a property that may be able to take advantage of these new rights, please do not hesitate to contact us for advice. 


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