Appeal Decision 233 - Certificate of Lawful Development.

April 2011 - Code a00233

Summary of Case (appeal dismissed): 

The property is a two-storey end-of-terrace house with a gable-end main roof. The property has previously been extended with a two-storey side extension, which is significantly set-back from the main front building line. The gable-end roof of the two-storey side extension joins onto the main gable-end roof, with the eaves and ridge-line of the former at a similar level to the eaves and ridge-line of the latter. The application was for a proposed rear dormer on the main rear roof (i.e. the rear roof of the original part of the house). 

The key issue was whether the proposed enlargement of the roof would be contrary to Class B, part B.1(c), which states that “Development is not permitted by Class B if … the cubic content of the resulting roof space would exceed the cubic content of the original roof space by more than— (i) 40 cubic metres in the case of a terrace house, or (ii) 50 cubic metres in any other case”. 

The Inspector stated the following: 

“The Council calculate that the proposal would increase the volume of the original roof at No. 54 by about 28 cubic metres. However, there has previously been a side extension to No. 54 the roof of which had a volume of about 73 cubic metres. Therefore, the combined volume of the proposal and the roof of the existing extension would be about 101 cubic metres. The appellant does not take issue with the calculations. 

Class B of Part 1 of the Town and Country Planning (General Permitted Development) Order 1995 (the Order) permits the enlargement of a dwellinghouse consisting of an addition or alteration to its roof. However, that development is not allowed if the cubic content of the resulting roof space would exceed the cubic content of the original roof space by more than 40 cubic metres in the case of a terrace house such as No. 54.  

The Order provides interpretation as to what the term “resulting roof space” means. It means the roof space as enlarged, taking into account any enlargement to the original roof space. 

The issue of whether the proposal is permitted development depends on whether the roof of the side extension is an enlargement to the original roof space. 

The roof of the side extension abuts part of the gable end of the original dwelling and in part overlaps part of the original rear roof slope. Having regard to the original roof of No 54 and the roof of the side extension I am of the view that the original roof space has been enlarged by the roof of the side extension. 

I therefore conclude that the proposal would not be permitted development because the volume of the proposed enlargement of the roof space combined with the volume of the roof space as enlarged by the side extension exceeds the 40 cubic metre limit.” 

Main Conclusions: 

·       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).
[Relevant to: “Interaction between Class A, Class B, and Class C”, Class A, A.1(i), Class B, B.1(c)].

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

·       Appeal Decision Notice:
http://planningjungle.com/?s2member_file_download=a00233-Appeal-Decision-Notice.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       OS Map:
http://planningjungle.com/?s2member_file_download=a00233-OS-Map.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

·       Drawings:
http://planningjungle.com/?s2member_file_download=a00233-Drawings.pdf&s2member_skip_confirmation&s2member_file_inline=yes 

Download documents and diagrams of useful

Permitted Development information