“Enlarged part of the dwellinghouse”

Part 1, Class A of the Second Schedule to the GPDO permits the enlargement, improvement or other alteration of a dwellinghouse, but paragraph A.1(e) provides that development is not permitted if the enlarged part of the dwellinghouse would extend beyond a wall which forms the principal elevation of the original dwellinghouse, or fronts a highway and forms a side elevation of the original dwellinghouse.

Subject to paragraph A.1(g),[see below], paragraph A.1(f) provides that development is not permitted by Class A if the enlarged part of the dwellinghouse would have a single storey and would extend beyond the rear wall of the original dwellinghouse by more than 4 metres in the case of a detached dwellinghouse, or 3 metres in the case of any other dwellinghouse, or would exceed 4 metres in height.

Paragraph A.1(g) (which allows larger extensions until 30th May 2019) provides that development is not permitted by Class A if the enlarged part of the dwellinghouse would have a single storey, and would extend beyond the rear wall of the original dwellinghouse by more than 8 metres in the case of a detached dwellinghouse, or 6 metres in the case of any other dwellinghouse, or would exceed 4 metres in height.

Similarly, in other cases, paragraph A.1(h) provides that development is not permitted by Class A if the enlarged part of the dwellinghouse would have more than a single storey and would extend beyond the rear wall of the original dwellinghouse by more than 3 metres, or would be within 7 metres of any boundary of the curtilage of the dwellinghouse opposite the rear wall of the dwellinghouse.

Paragraph A.1(i) provides that development is not permitted by Class A if the enlarged part of the dwellinghouse would be within 2 metres of the boundary of the curtilage of the dwellinghouse, and the height of the eaves of the enlarged part would exceed 3 metres.

Finally Paragraph A.1(j) provides that development is not permitted by Class A if the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse, and would exceed 4 metres in height, or would have more than a single storey, or have a width greater than half the width of the original dwellinghouse.

In the same way, paragraph A.2(b) provides that, in the case of a dwellinghouse in a conservation area, and area of outstanding natural beauty, a National Park, the Broads or a World Heritage Site, development is not permitted by Class A if the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse, and paragraph A.2(b) provides that, in those same areas, development is not permitted by Class A if the enlarged part of the dwellinghouse would have more than a single storey and extend beyond the rear wall of the original dwellinghouse.

In all these cases, therefore, it is necessary to determine what is meant by “the enlarged part of the dwellinghouse”, and it is also necessary in this context to understand what is meant by the original dwellinghouse.. These were the questions that the High Court had to consider in Hilton v SSCLG (CO/309/2016) in which judgment was given on 16 June.

The Hilton case arose from a planning appeal in the London Borough of Bexley [3129892] against the refusal of prior approval for a householder proposal for a larger home extension. The proposed single storey rear extension would project some 2.3 m beyond the existing rear wall of this previously extended semi-detached house. As the proposed extension, together with the existing extension, would project some 5.1m to the rear of the main rear wall of the original dwelling, the overall enlargement of the house would not exceed 6.0m. On this basis, and because the maximum height of the new extension would be around 2.8m, the appellant submitted that it would be permitted development.

The basis of the dispute between the Claimant and the LPA was that the Council maintained that even though the additional extension now proposed would have only a single storey, the enlarged part of the house would include more than a single storey, whereas the appellant contended that the enlarged part [i.e. the currently proposed extension] would have a single storey. (There was no dispute that the existing extension includes both two-storey and single-storey elements.)

In dismissing the appeal, the Inspector referred to Kensington and Chelsea RBC v SSCLG [2015] EWHC 2458 (Admin), which had examined the question of whether existing extensions are part of the enlargement of a building, and where it was held that the ‘enlarged part of the dwellinghouse’ does not include the ‘original’ building, but does include previous enlargements. The inspector therefore concluded that the proposed extension would, taken together with the existing extension, not be a single-storey enlargement to the dwellinghouse. It would not, therefore, be permitted development under the terms of Part 1 Class A.1 (g)(i) of the GPDO. Furthermore, as the enlarged part of the house would exceed 4 m in height on account of part of the existing extension having two storeys, the proposal would not be permitted development under the terms of Part 1 Class A.1 (g) (ii) of the GPDO.

Unfortunately, the transcript of the Hilton judgment is still not available, but I understand from a statement issued by Landmark Chambers that the court held that the Inspector was wrong, and that the "enlarged part" of a dwellinghouse for the purposes of Class A included only that which was currently being proposed under Class A. We shall have to await the transcript to see how the Deputy Judge distinguished the Kensington and Chelsea judgment in reaching this decision.

Another point that also remains unexplained until we have the chance to read the transcript is that this judgment is clearly at variance with DeCLoG’s Technical Guidance on “Permitted Development Rights for Householders”. This states (under “General Issues”) that :

[1] “Original”** means a building as it existed on 1 July 1948 where it was built before that date, and as it was built if built after that date, and

[2] “Enlarged part of the house” is the part(s) of a dwellinghouse comprising any enlargements of the original house, whether built under permitted development rights or following any application for planning permission, and whether the enlargement is undertaken on a single occasion or added incrementally. [In other words, the enlarged part of the dwellinghouse, so the Secretary of State says, includes cumulative extensions, in addition to the further extension currently under consideration.]

[** This is in contrast to the interpretation of “Existing” which means (according to the Technical Note) a building as it existed immediately before the permitted development (for example a house extension) is undertaken. The existing house will include previous development to the house, whether undertaken as permitted development or as development resulting from a planning permission from the local authority.]

In relation to paragraph A.1(g), the Technical Note states that from 30 May 2013 until 30 May 2019 a single-storey extension can be larger than allowed under paragraph (f) but it must not extend beyond the rear of the original house by more than 8 metres if a detached house, or by more than 6 metres in any other case. These larger extensions are subject to a prior approval procedure, whereas single-storey extensions that do not extend beyond the rear of the original house by more than 4 metres if a detached house, or by more than 3 metres in any other case, (as set out in paragraph (f) above) are not subject to a neighbour consultation scheme.

Permission to appeal to the Court of Appeal was refused by the Deputy Judge, but I do not know yet whether that application has been renewed before the Court of Appeal.

I will return to this topic in light of the transcript of the judgment when it becomes available, and in light of any further proceedings in the event of the case being taken further.

ADDENDUM: Since I posted this item on Friday, a further thought has occurred to me. It seems to me that to concentrate on the phrase “the enlarged part of the dwellinghouse” may be missing the point. Surely the wording of this provision in the GPDO by reference to the “the rear wall of the original dwellinghouse” must be the key to assessing whether or not a proposed extension is or is not permitted development under Part 1, Class A.

It matters not whether or not any previous extensions have been built or what size they were. I quoted the definition of “original” in De-CLoG’s Technical Guidance note, but the meaning of the this word is in fact defined in the GPDO itself, in Article 2(1). So this is a statutory definition. The measurement that needs to be made in order to determine whether a currently proposed extension is or is not permitted development depends entirely on how far it extends from the rear wall of the house as it existed on 1 July 1948 or, if built after that date, as first built.

Unless I have missed something (which may be revealed by the transcript of the judgment in Hilton) this would seem to be the answer to the dispute that arose in that case. If any ambiguity may possibly arise from the use of the phrase “the enlarged part of the dwellinghouse”, this could more readily be resolved by a simple amendment to the GPDO (which is due to be amended in any event in the near future), rather than resorting to the Court of Appeal in an effort to reverse the High Court decision in Hilton.

© MARTIN H GOODALL