Appeal Decision 224 - Certificate of Lawful Development.

March 2011 - Code a00224

Summary of Case (appeal allowed): 

The property is a two-storey detached house set within very considerable grounds. The south-east elevation is the principal elevation, and does not front a highway. The application was for a proposed two-storey front extension, with a roof that would join onto the roof of the main house. 

The key issue was whether the proposed extension would be contrary to Class A, part A.1(i), which states that “Development is not permitted by Class A if … it would consist of or include … an alteration to any part of the roof of the dwellinghouse”. 

The Inspector stated the following: 

“Both parties accept that the proposed extension complies with the limitations in paragraphs A.1(a)-(h) of Class A of Part 1 of Schedule 2 to the GPDO and I see no reason to disagree. Both parties also accept that the proposal would involve an alteration to part of the roof of the dwellinghouse. However, the Council consider that the alteration of the roof falls to be considered under Class B of Part 1 of Schedule 2 to the GPDO “The enlargement of a dwellinghouse consisting of an addition or alteration to its roof”; whereas the Appellant considers that the alteration to the roof falls to be considered under Class C of Part 1 of Schedule 2 to the GPDO “Any other alteration to the roof of a dwellinghouse.” 

The issue between the parties is whether the proposal is an enlargement consisting of an addition or alteration to the roof of the dwellinghouse or whether it is an ‘other’ alteration of the roof. The development would enlarge the roofspace of the dwellinghouse, but it would not solely consist of an addition or alteration to the roof. It would be a two storey extension that included an alteration to the roof. 

The Technical Guidance supports this interpretation and on pages 7 and 8 it states;

 

“…. changes to the roof of a house are not permitted development under Class A, but may be permitted development under Class B or C. For example, where a proposed two storey extension at the rear of a house has a roof that joins onto the main roof of the original house, the works will need to meet the requirements of both Class A (which covers the enlargement of the house) and Class C (which covers any alterations to the roof) in order to be permitted development. If the works also include the creation of a dormer window to enlarge the roof space, either in the extension or the original roof space, then they would also need to meet the requirements of Class B.” 

In my view, for the proposal to be considered under Class B it would need to be a stand alone element of the proposal which consisted only of an addition or alteration to the roof, such as a dormer window. The proposal does not do this and therefore does not fall to be considered under Class B. 

Paragraph C.1(a) of Class C states that development is not permitted by Class C if; 

“the alteration would protrude more than 150 millimetres beyond the plane of the slope of the original roof when measured from the perpendicular with the external surface of the original roof.” 

The ridge of the extension would be perpendicular to that of the roof to the original house. The point at which the extension roof would join or attach to the existing roof of the dwelling would be the alteration to the roof. The actual proposed roof structure would be permitted under Class A up until the point at which it attached to the existing roof of the dwelling, and it would not therefore, in my view, amount to a protrusion for the purposes of Class C. As such the limitation of a protrusion of no more than 150mm would not apply. 

My view is reinforced by the Technical Guidance at page 37, which states  

“This limitation to projection from the roof plane should not be applied in cases where the roof of an extension to a house that is permitted development under Class A is joined to the roof of the original house. In such cases, the roof of the extension should not be considered as protruding from the original roof.” 

For the reasons given above I conclude, on the evidence now available, that the Council’s refusal to grant a certificate of lawful use or development in respect of a two storey front extension was not well-founded and that the appeal should succeed. I will exercise the powers transferred to me under section 195(2) of the 1990 Act as amended.” 

[Note: The Inspector has concluded that where a Class A extension would have a roof that would join onto the roof of the main house, but the roof of the extension would not contain any dormers / rooflights / habitable rooms / etc, then the extension should also be assessed against Class C (and not Class B), ignoring the 150mm projection limit. It should be noted that this interpretation is directly based on the advice in the “DCLG - Permitted development for householders - Technical guidance” (August 2010) document. 

Notwithstanding the latter fact, in my opinion this interpretation is very contrived and questionable. I really do not see why a Class A extension that joins onto the roof of the main house should be subject to the 40m3/50m3 volume limit (i.e. under Class B) if its roof contains a habitable room, but not subject to the 40m3/50m3 volume limit if its roof does not contain a habitable room. The 40m3/50m3 volume limit is clearly designed to limit the degree of extensions that are allowed at roof level, which seems clearly due to visual reasons, so why should its application depend on whether the inside of the roof of the extension contains a habitable room … ? A major contradiction with this interpretation is that it would appear to allow someone to circumvent the 40m3/50m3 volume limit by building (and completing) a Class A extension with a roof that doesn’t contain a habitable room, and then subsequently inserting a habitable room (either without rooflights, which wouldn’t constitute development, or with rooflights, which would be allowed under Class C). Furthermore, the idea that an extension with a roof that doesn’t contain a habitable room should be assessed against Class C, but that when making this assessment the main limitation of Class C (i.e. the 150mm projection limit) should be ignored, seems very contrived. 

It should be noted that a number of appeal decisions have concluded that where there is an existing extension with a roof that joins onto the roof of the main house, then this will reduce the volume allowance that remains for roof extensions under Class B, part B.1(c), and that furthermore, even if the roof of the existing extension does not contain any dormers / rooflights / habitable rooms / etc, this will still reduce the volume allowance that remains for roof extensions under Class B, part B.1(c). In my opinion, this would add another major contradiction, as it would mean that if proposing a Class A extension with a roof that doesn’t contain a habitable room then this would not be subject to the 40m3/50m3 volume limit, and yet as soon as the extension is built it will then reduce the volume allowance that remains for other subsequent extensions]. 

Main Conclusions: 

·       Class A does permit an extension with a roof that would join onto the roof of the main house.
[Note: This would appear to contradict at least one other appeal decision – for further information see the entry in the “Reference Section” on “Interaction between Class A, Class B, and Class C”].
[Relevant to: “Interaction between Class A, Class B, and Class C”, Class A, A.1(i), Class B, B.1(c)].

·       Where a Class A extension would have a roof that would join onto the roof of the main house, but the roof of the extension would not contain any dormers / rooflights / habitable rooms / etc, then the extension should also be assessed against Class C (and not Class B), ignoring the 150mm projection limit.
[Note: This would appear to contradict at least one other appeal decision – for further information see the entry in the “Reference Section” on “Interaction between Class A, Class B, and Class C”].
[Note: In my opinion, this interpretation is very contrived and questionable].
[Relevant to: “Interaction between Class A, Class B, and Class C”, Class A, A.1(i), Class B, B.1(c)].

·       Where the principal elevation does not front a highway, an extension can extend in front of the principal elevation.
[Relevant to: “Principal Elevation”, A.1(d)].

·       Furthermore, in such cases, the amount by which the extension can extend beyond the principal elevation does not appear to be directly* restricted by any limitation.
(*i.e. other than the general requirement to remain within the “curtilage”, and the general restriction of A.1(a) that prevents more than 50% of the original garden being covered by buildings).
[Relevant to: “Principal Elevation”, A.1(d)].

Links to the “Appeal Decision Notice” and other associated documents (e.g. drawings, etc): 

·       Appeal Decision Notice:
http://planningjungle.com/?s2member_file_download=a00224-Appeal-Decision-Notice.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       OS Map:
http://planningjungle.com/?s2member_file_download=a00224-OS-Map.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       Floor Plans:
http://planningjungle.com/?s2member_file_download=a00224-Floor-Plans.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       North-East Elevations:
http://planningjungle.com/?s2member_file_download=a00224-North-East-Elevations.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       South-East Elevations:
http://planningjungle.com/?s2member_file_download=a00224-South-East-Elevations.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       South-West Elevations:
http://planningjungle.com/?s2member_file_download=a00224-South-West-Elevations.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

Download documents and diagrams of useful

Permitted Development information