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Appeal Decision 218 - Certificate of Lawful Development.

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March 2011 - Code a00218


Summary of Case (appeal dismissed): 


The property is a detached house with a chalet type design. On either side, the house has a ground floor level with a hipped roof above. In the centre, the house has a first floor level which is visible at the front (i.e. appearing as two-storeys with a standard hipped roof above), although at the sides and rear the hipped roof of this central part merges with the hipped roofs of the side parts (i.e. appearing as a single storey with double-height hipped roof above). 


A rear extension has previously been constructed, the first floor of which consists of a hipped roof with projecting dormers that joins onto the lower half of the double-height main roof. The application was for a proposed roof extension above this rear extension that would join onto the upper half of the double-height main roof. As all of the above is relatively difficult to describe, please see the submitted drawings 


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 appellant does not dispute that additions to the original roof space that have occurred already, including any that result from the existing 2 storey rear extension which was found to be lawful by virtue of an LDC (Ref. No. WA/2010/0888) granted on 20 July 2010, have to be included. However he claims that the amount of roof space to be added as a result is only the roof void above the permitted 2 storeys of living accommodation which he calculates as being 7.2 cu.m. Added to this is the roof volume of a single storey side extension calculated as being 6.2 cu.m. and the calculated volume of 16.97 cu.m. for the proposed roof extension shown on Drawing No. 598- P50b. This gives a total of 30.37 cu.m. below the 50 cu.m. limit. 


The onus of proof in such cases is on the appellant. He argues that, to his knowledge, there is no definition of roof space in the GPDO 2008 or the technical guidance notes published by the Department for Communities and Local Government. I am also not aware of any specific definition and it is therefore a matter of interpretation having regard to the nature of the development and the wording of the relevant part of the GPDO. 


I have taken account of the nature of the development confirmed as being lawful by LDC - WA/2010/0888 which is said to only refer to Class A of the GPDO in the decision. I have not been provided with a copy of this but the Council have not disputed this assertion. The appellant argues that because the works permitted as lawful were a 2 storey extension and not a single storey with roof extension, it is not correct to include the living accommodation in the roof lit by two rear-facing dormer windows. 


The “Interpretation of Class B” paragraph in the GPDO indicates that enlargements to the original roof space can come about by virtue of Class B or for other reasons. I see this as being so by the inclusion of the words “or not” at the end. If the intention was to only include resulting roof space added by virtue of Class B then these extra words would be superfluous. They are clearly there for a purpose and I take it that this means that roof space can be added as a result of a planning permission or on the basis of additions that are permitted development under Class A of the GPDO. I consider this is a logical conclusion to draw as Class A makes a number of references to roofs and includes extensions of more than one storey, which will add to the volume of resulting roof space unless they are flat-roofed. So I do not accept that simply because the previous LDC apparently referred to Class A that the 2nd storey of accommodation should necessarily be excluded from what is considered to be the resulting roof space. 


The question to ask, it seems to me, is whether the first floor of accommodation already added amounts to an addition to the resulting roof space. In this respect, it is matter of the nature of the development created and its design. If the two storey addition was effectively constructed of walls with a pitched roof above then I would agree that it would only be the roof void that would be reckonable. However, in this case, the eaves height is only at the top of the lower storey with a hip-ended roof envelope above containing the second storey of accommodation. Taking a pragmatic approach, the conclusion I draw is that the second storey of accommodation sits within the resulting roof space and that this volume should be included and not just the roof void above the ceiling of the second storey, as calculated by the appellant. 


I have no figures to show what this volume would be but it would be a significant increase on what the appellant calculates and this could take the total for the resulting roof space (existing and proposed) above the 50 cu.m. limit. In the absence of any clear figures to show otherwise I do not consider that the onus of proof that the proposed development is lawful has been discharged. I therefore conclude that the Council’s refusal to grant a LDC in respect of the proposed development was well-founded and that the appeal should fail. Accordingly, I will exercise the powers transferred to me in section 195(3) of the 1990 Act as amended and dismiss the appeal.” 


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)].


·       In an application for a certificate of lawfulness, the burden of proof is firmly on the applicant.
[Relevant to: "General”].


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


·       Appeal Decision Notice: 

·       Drawings: 




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