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Appeal Decision 105 - Certificate of Lawful Development.

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March 2010 - Code a00105


Summary of Case (appeal dismissed): 


The property is a two-storey detached house. Prior to 01/10/2008, a certificate of lawfulness was issued for a rear dormer that would have covered the full width and height of the rear roof, with no eaves remaining. Although a dormer has been constructed with these dimensions, the Inspector states in the appeal decision notice that the development started after 01/10/2008, and that therefore the amended Part 1 is applicable. Furthermore, the Council states in their report that the ground floor extension started prior to the completion of the rear dormer, resulting in the latter exceeding the volume tolerances. This current application involved the proposed reintroduction of the eaves. 


The key issue was whether the rear dormer is contrary to Class B, part B.2(b), which states that “Development is permitted by Class B subject to the following conditions … (b) other than in the case of a hip-to-gable enlargement, the edge of the enlargement closest to the eaves of the original roof shall, so far as practicable, be not less than 20 centimetres from the eaves of the original roof”. 


The Inspector stated the following: 


“I now turn to the question of the relationship of the dormer with the eaves of the building. Unfortunately the General Permitted Development Order does not define the term “eaves”. However, in my experience it usually refers to the overhanging or projecting part of a sloping roof, where a roof is designed with its outer edge projecting beyond the wall below. This opinion is supported by the definitions given in technical publications dealing with such matters. The fundamental problem in this case is that at present there are no eaves on the rear elevation of the building, which is a three-storey vertical wall below a flat roof. Since the eaves no longer exist, I fail to see how the 20 centimetre set back required by condition B.2(b) can be provided as there is no roof plane on which the distance can be measured.  


The appellants argue that the dormer is over 20 centimetres from the outer edge of the former eaves, which clearly projected beyond the face of the rear wall of the building. However, in my view such an interpretation would conflict with the aim of the requirement, which clearly seeks that part of the sloping area of the original roof be retained when such extensions are constructed. In my opinion the phrase “so far as practicable” is clearly intended to give some flexibility to local planning authorities, particularly when dealing with unusual types of building. Nevertheless, it cannot have been intended to make the requirement for a dormer to be set back wholly discretionary, as this would effectively allow over-large dormers to be created and frustrate the aim of the requirement. Moreover, I note that the parties accept that in this case it would be possible to erect a dormer set back 20 centimetres from the rear wall of the building. I therefore conclude that in its present form the dormer requires planning permission. 


In reaching this decision I have had regard to the diagram on the Planning Portal which illustrates the requirements of the General Permitted Development Order. I consider that this drawing shows that the aim of the Order is that there should be a significant gap between the edge of the roof and the front of the dormer. The absence of any gap would clearly not satisfy this objective. 


I now turn to the question of whether the dormer would become permitted development if a new “eaves” was introduced in a similar position to the former eaves. This is the matter on which the appellants sought clarification in the Lawful Development Certificate application that is the subject of Appeal B. In my view the scheme the appellants propose could not be regarded as the installation of eaves in the normal sense of this term but would merely be the introduction of a decorative feature onto the rear elevation of the building. This would be physically divorced from the roof of the dwelling, as it now exists, by a distance of some three metres and would play no part in the function of the roof. Therefore in my opinion the proposal would not make the dormer permitted development.” 


The Inspector also concluded that the use of white render on the rear dormer was contrary to Class B, part B.2(a) [which requires that “the materials used in any exterior work shall be of a similar appearance to those used in the construction of the exterior of the existing dwellinghouse”] on the basis that before the recent building works commenced the predominant materials of the property were brick and clay tiles. 


Main Conclusions: 


·       It is not possible to comply with Class B, part B.2(b) if the original eaves have been removed.
[Relevant to: B.2(b)].


·       In order for a dormer extension to comply with Class B, part B.2(b), there needs to remain a continuous strip of at least 20cm of original roof slope below the base of the dormer. It is not possible to comply with this condition by saying that the dormer would be set-back 20cm from the notional point where the original eaves would have been when the latter has been removed.
[Note: This would appear to contradict at least one other appeal decision – for further information see the entry in the “Reference Section” on “B.2(b)”].
[Relevant to: B.2(b)].


·       Furthermore, in such a case where a dormer doesn’t comply with Class B, part B.2(b) because the original eaves have been removed, it is not possible to comply with this condition by reintroducing the eaves.
[Relevant to: B.2(b)].


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


·       Appeal Decision Notice: 

·       OS Map: 

·       Drawings 1: 

·       Drawings 2: 

·       Drawings 3: 

·       Council’s Report: 






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