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Appeal Decision 228 - Certificate of Lawful Development.

This appeal decision summary and assessment has been produced by Planning Jungle Limited.  For more information, please go to


April 2011 - Code a00228  


Summary of Case (appeal dismissed): 


The property is a detached house.  The application was for an existing outbuilding, which consists of a swimming pool (with plant room, shower & wc, and changing area) and a gym / games area (total footprint over 110m2).  The outbuilding has a mansard type roof, with shallow pitches in the centre and steeper pitches on either side (see drawings).  The central ridge-line is at height 4.0m. 


The key issue was whether the outbuilding is contrary to Class E, part E.1(d), which states that “Development is not permitted by Class E if … the height of the building, enclosure or container would exceed … (i) 4 metres in the case of a building with a dual-pitched roof, (ii) 2.5 metres in the case of a building, enclosure or container within 2 metres of the boundary of the curtilage of the dwellinghouse, or (iii) 3 metres in any other case”. 


The Inspector stated the following: 


“The outbuilding would comply with paragraph E.1(d)(ii), because of its location from the site’s boundaries. The roof would have a single apex from which the height of the building could be taken. The roof structure would be broken to form two sets of planes on each side of the central ridgeline and the outer planes would be slightly steeper because of their pitch. The slopes would be joined to form separate horizontal ridgelines, which the appellant refers to as ‘knuckle’ joints. The design of the roof would be simple and it would have low eaves. Both parties describe the roof as a ‘gambrel’ or ‘mansard’ type. The gist of the appellant’s main argument is that paragraph E.1(d)(iii) would not apply because the mansard is a ‘dual-pitched’ roof, that the outbuilding would be 4m high thereby complying with paragraph E.1(d)(i). 


The GPDO does not define a ‘dual-pitched’ roof and there is no indication that the question as to what constitutes a ‘dual-pitched’ roof for the purposes of paragraph E.1(d) has been considered by the court. My attention was drawn to a definition of a ‘mansard’ roof in the ‘Illustrated Dictionary of Building’, which describes the roof as a ‘double-pitched roof where each slope has two pitches. The lower part has a steep pitch, the upper part rarely exceeds thirty degrees. The ends may be hipped or gabled’. It is contended that the words ‘double-pitched’ should be substituted by ‘dual-pitched’. However, this would not be consistent with the manner in which the mansard roof design is defined in the dictionary. In any event, the appellant concedes that this definition is not decisive and I have to apply the terms of the GPDO to the proposed development. 


To assist with the interpretation of the amendments to the GPDO, technical guidance was produced by the Department for Communities and Local Government (‘DCLG’) titled ‘Permitted development for householders, technical guidance’ (August 2010). Given the very substantial variations in the design of individual houses, the guide cannot cover all possible situations that may arise. The guidance gives an explanation of the rules on PDRs for householders, what these mean and how they should be applied in particular sets of circumstances. I take the view that where the guidance does not cover a particular situation it is acceptable to consider the reasons behind the amendments to the GPDO, which were impact based. 


The technical guidance suggests that the height limit on a ‘dual-pitched’ roof of 4m should also be applied to buildings that have ‘hipped’ roofs (slopes on all four sides). Clearly, the logic appears to be that a hipped roof structure is likely to have a less bulky appearance, because of its roof design, thereby reducing its visual or amenity impact, than say, a gabled roof of similar height due to its built-form. The technical guidance does not make a similar concession to mansard or gambrel roof designs. In my opinion, the extension of the interpretation of paragraph E.1(d)(i) to hipped roofs cannot automatically be applied to any other form of roof design, due to the specific use of the words ‘dual-pitched’ in paragraph E.1(d)(i). Therefore, I disagree with the interpretation that the phrase ‘dual-pitched’ roof encompasses the proposed roof type, which would be of greater bulk than a dual-pitch roof and have more of an impact. Contrary to the appellant’s arguments, in this case paragraph E.1(d)(i) would not apply.” 


Main Conclusions: 


·       The phrase “dual-pitched roof” does not apply to an outbuilding with a mansard / crown type roof (i.e. either a roof with shallow pitches in the centre and steeper pitches at the sides, or a roof with a flat area in the centre and pitches at the sides).
[Note: This would appear to contradict at least one other appeal decision – for further information see the entry in the “Reference Section” on “E.1(d)”].
[Relevant to: E.1(d)]. 


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


·       Appeal Decision Notice: 

·       OS Map: 

·       Floor Plan: 

·       East Elevation: 

·       South Elevation: 



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