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Appeal Decision 137 - Certificate of Lawful Development.

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September 2010 - Code a00137


Summary of Case (appeal dismissed): 


The property is a two-storey semi-detached house, with a hipped roof. In 2008 planning permission (reference H/01121/08) was granted for various works. These works included a two-storey side extension, which would have had a hipped roof with a ridge-line at a slightly lower level than the main ridge-line. These works also included a small rear dormer, which would have been located entirely on the original main rear roof slope. 


The above works have been constructed, but with several differences. The main ridge-line has been extended sideways, such that the pitch of the main hipped roof has been increased. A much larger rear dormer has been constructed, which is located not only on the original part of the main rear roof slope but also on the extended part of the main rear roof slope. The application was for a certificate of lawfulness, which appears to be on the basis that the larger rear dormer was permitted development (e.g. no more than 50m3, etc). 


The Inspector stated the following: 


“After examining the information before me and carrying out my site visit, I consider that the dormer is physically inseparable from the main roof of the house which has itself been the subject of works including a roof extension over a new two storey side extension. Evidence indicates that the two storey extension and the roof extensions (including the dormer) were constructed as one operation. Consequently, it is my view that the dormer should be considered as an integral part of one building operation which includes the construction of roof extensions and the two storey side extension. 




I now need to look at whether “the rear dormer for loft conversion” constitutes permitted development. If the works to the roof were to be considered without being part of an operation which included the erection of two storey side extension, the dormer would be permitted development for the purposes of Article 3 and Class B of Part 1 to Schedule 2 of the Town and Country Planning (General Permitted Development) Order 1995 (“the GPDO”). In this context, the additions to the roof do not exceed the highest part of the existing roof and the works do not extend beyond the plane of any existing roof slope which fronts a highway. The Council has estimated that the roof extension volume is 37.4 cubic metres (less than 50 cubic metres) and the dwellinghouse is not on Article 1(5) land. 


However, for the reasons set out in paragraph 8, I believe that the dormer should not be looked at in isolation. Rather, the dormer should be considered as an integral part of one building operation which includes the roof extensions and also the two storey side extension. Whilst the roof extensions would be permitted development, this would not be the case with the two storey side extension. Class A of Part 1 to Schedule 2 of the GPDO does permit the enlargement of a dwellinghouse provided certain criteria are met. Paragraph A.1(h) of Class A relates to the enlarged part of a dwellinghouse which would extend beyond a wall forming a side elevation of the original dwellinghouse. Here development is not permitted if the enlarged part would, amongst other matters, have more than one storey. It follows that the two storey side extension is not permitted development. 


Given that the works the subject of this appeal form part of an operation which includes other works (the two storey side extension) which are not permitted development, the rear dormer, as part of the larger operation, cannot benefit from rights under the GPDO. I therefore find that in this particular case the dormer is not permitted development under Class B of Part 1 to Schedule 2 of the GPDO.” 


Main Conclusions: 


·       It is not possible as a single operation to erect an extension where part of it has been granted planning permission by the Council and the other part is permitted development.
[Relevant to: “General”].


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


·       Appeal Decision Notice: 

·       Drawings: 

·       2008 Planning Permission: 






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