“5. I acknowledge that the appellant has designed the extension so as to minimise its visualimpact and I accept that it would be set back far enough so as not to be readily seen from the street in front of No 26. However, I do not consider that this would be the case in medium range views, and in particular those from the junction of St Stephen’s Gardens and Chepstow Road. From what I saw on my visit, I am satisfied that the new party wall would be clearly seen from here and would be a prominent intrusion above the plain parapet. In my opinion, this would cause harm to the architectural integrity of the terrace and would conflict with the provisions of policy DES6. This says, among other things, that roof extensions are not acceptable in terraces where the existing roof-line is largely unimpaired. I consider that the relatively unspoilt appearance of the terrace makes a significant contribution to the conservation area and the appeal scheme would not preserve its appearance. I know that to some extent this has been prejudiced by the extension at No 28, but this was allowed prior to the current policies and I do not consider that it provides a good reason for allowing further visual harm. 6. The Council are concerned also about the effect of the proposed extension on the rearof the terrace, where the roof-line has a traditional butterfly form. Policy DES6 of the UDP seeks to protect unbroken runs of butterfly roofs and I accept that the proposed extension would sit uncomfortably within such a roof pattern. However, there are very limited public views of the rear roof pattern and the Council concede that the rear of No 26 itself is screened by other buildings. In these circumstances, I do not consider that this particular conflict with policy is sufficient to justify on its own the refusal of planning permission.”
“5. No 4 has been designated by the Council as an unlisted building of merit within the Conservation Area. The terrace within which it is situated has a straight roofline to the front formed by a horizontal parapet. The proposed extension has been designed so that its position and height in relation to the chimneys and front parapet would mean that it would not be visible in views from the front of the dwelling in St Stephens Gardens. I am satisfied that these features would mean that it would also not be evident in longer views in the street scene. The top of the appeal extension may be glimpsed in private views from the upper floors of properties opposite but this impact would be so limited that it would be insufficient reason by itself to dismiss the appeal. 6. Whereas there is a flat roof at No 6 St Stephens Gardens and a roof extension at No 28, the pattern of butterfly roofs on the terrace is otherwise undisturbed by any significant roof alterations. However, the appeal building and its neighbour at No 6 have been extended to the rear. As a result, while No 4 has a butterfly roof there is also a small flat roof area to the rear. Neither property has the v-shaped rear parapet characteristic of buildings with butterfly roofs in the locality. However a butterfly parapet would be included in the appeal scheme. No 4 is towards the end of the terrace, close to the junction with Westbourne Park Road. The rear of the appeal property can be seen from that road in a gap between buildings but I consider that the existing extension would conceal the proposed mansard and dormers from this viewpoint and as such they would not be visible in any public views. However, these features would be seen from other properties to the rear of the dwelling.”
“In my estimation the distinctive straight roofline at the front of the terrace would not be harmed by the appeal proposals. In the context of the existing rear extension and absence of public views, the alterations to the butterfly roof would not have a detrimental effect in this instance. As such, I conclude that the proposed development would preserve the character and appearance of Westbourne Conservation Area. It would not conflict with the aims of Policies DES 1, DES 6 and DES 9 of the City of Westminster Unitary Development Plan and Policies CS 24 and CS 27 of the City of Westminster Core Strategy.”
“Roofs: A Guide to Alterations and Extensions on Domestic Buildings”, “Development and Demolition in Conservation Areas” and its “Westbourne Conservation Area Audit”.”
“… [The] roof extension would be invisible from the street and the roofline of the property and the group of which it forms a part would not be affected. The distinctive straight roofline of the terrace will not be harmed by the proposals. To the rear, the butterfly shaped parapet would be retained. The rear of the building is not visible from any public viewpoints and has limited visibility from private views. The proposals therefore will not cause harm to the appearance of the building, street scene or Westbourne Conservation Area.”
“An appeal relating to a similar extension at No.4 St Stephen’s Gardens was allowed in 2011 (decision notice and plans attached at Appendix 1). It is considered that significant weight should be given to this decision. The Inspector made two key observations relating to that extension in response to the Council’s refusal … on the grounds that the Conservation Area’s unbroken rooflines would be affected. Firstly, that the extension would not be visible from the front as a result of the design which locates the extension behind the front parapet. The Inspector noted that it would neither be visible from in front of the building nor from long views along the street. He noted that whilst the extension may be “glimpsed in private views from the upper floors of properties opposite”, the impact would be “so limited that it would be insufficient reason by itself to dismiss the appeal”
“To the rear of the property, again the proposed roof extension will not be visible from Westbourne Park Road where there is a small gap affording some view along the rear of the terrace, due to the set back from the rear elevation and due to the projecting extensions at nos. 4 and 6 St Stephen’s Gardens concealing the roof from view. Nor will it be visible from St Stephen’s Mews where it is not possible to see the rear elevations or roofs of the appeal terrace.”
“The Inspector at no. 4 also discussed the rear of the building. No. 4 St Stephen’s Gardens had been altered at the rear, with a rear extension and the insertion of a small flat roof terrace which had resulted in the loss of the v shaped parapet beyond the retained butterfly roof. The proposals reinstated the v shaped parapet at the rear of no.4. At no.10 St Stephen’s Gardens, the butterfly roof remains as does the v shaped parapet. The proposed roof extension will maintain the v shaped parapet at the rear. The reason for refusal relating to this appeal said that because the extension would lead to the loss of the original roof form, the extension would harm the building.” and in paragraph 5.23: “The Inspector noted in his decision relating to no.4 that the extension would not be visible from the rear except from the other properties facing it, and went on to reference the decision of another Inspector relating to an appeal decided in 2001 for another similar extension at 26 St Stephen’s Gardens (… attached at Appendix 2). In this particular decision, the Inspector dismissed the appeal, but pointed out that as the rear of that building was screened from public views, concern over the impact on the butterfly roof was insufficient to justify on its own the refusal of planning permission. Considering the effect of the extension on views from the rear at no. 4, and the loss of the butterfly roof form, the Inspector stated[:] “in the absence of public views, the alterations to the butterfly roof would not have a detrimental effect in this instance. As such I conclude that the proposed development would preserve the character and appearance of the Westbourne Conservation [Area].”
“Permission may be refused for roof level alterations and extensions to existing buildings in the following circumstances: 1) where any additional floors, installations or enclosures would adversely affect either the architectural character or unity of a building or group of buildings; 2) where buildings are completed compositions or include mansard or other existing forms of roof extension; 3) where the existing building’s form or profile makes a contribution to the local skyline or was originally designed to be seen in silhouette; 4) where the extension would be visually intrusive or unsightly when seen in longer public or private views from ground or upper levels; 5) where unusual or historically significant or distinctive roof forms, coverings, constructions or features would be lost by such extensions.”
“12. I accept that [the proposed development] would not be readily visible from ground level at the front or the back and that some expression of the butterfly form would remain at the rear with the retention of the parapet, although it would be visible from the upper floors of surrounding properties. However, the distinctive character of terraces such as this depends not only on the strong and cohesive architectural style of the main elevations but also on the less obvious elements at roof level. 13. Where these survive they help to maintain the unity of the group of buildings and make a valuable and significant contribution to the overall character of the conservation area. To allow this extension would result in an erosion of the character of the terrace, which although relatively limited in itself, would if subsequently repeated, have a cumulative effect which would cause significant harm to the character and appearance of the conservation area. 14. There are a small number of properties in this part of St. Stephens Gardens which have roof extensions. There is some disagreement between the appellant and the Council regarding the history and circumstances of the construction of these. I have taken account of previous Inspectors’ more recent decisions on extensions to properties in the street and elsewhere which have been brought to my attention, particularly in respect of the limited visibility of the extension from street level and of the existence of any earlier alterations to the roof in some of those cases. 15. However, the Council has had clear policies in place for many years to protect the historic environment which it considers to be one of its greatest assets. These policies have been brought up to date in the City Plan and are consistent with the Framework. The latter stresses that heritage assets are an irreplaceable resource and that they should be conserved in accordance with their significance. 16. I conclude that the proposal would fail to respect the architectural character of the building and the terrace as a whole because of its design and because it would result in the loss of a distinctive roof form. It would therefore cause unacceptable harm to the character and appearance of the building and would not preserve or enhance the character of the wider conservation area in general. It is contrary to City Plan policies S25 and S28, UDP policies DES 1 and DES 6, the SPG and the Framework. 17. In determining this appeal I have given careful consideration to all the representations made and all other matters raised. I have considered the proposal on its own merits and in the context of relevant planning policies and I have found nothing to alter my conclusion that for the reasons given above, the proposal is contrary to local and national planning policies and the appeal should not succeed.”
“… It was not disputed in argument that a previous appeal decision is capable of being a material consideration. The proposition is in my judgment indisputable. One important reason why previous decisions are capable of being material is that like cases should be decided in a like manner so that there is consistency in the appellate process. Consistency is self-evidently important to both developers and development control authorities. But it is also important for the purpose of securing public confidence in the operation of the development control system. I do not suggest and it would be wrong to do so, that like cases must be decided alike. An inspector must always exercise his own judgment. He is therefore free upon consideration to disagree with the judgment of another but before doing so he ought to have regard to the importance of consistency and to give his reasons for departure from the previous decision. To state that like cases should be decided alike presupposes that the earlier case is alike and is not distinguishable in some relevant respect. If it is distinguishable then it usually will lack materiality by reference to consistency although it may be material in some other way. Where it is indistinguishable then ordinarily it must be a material consideration. A practical test for the inspector is to ask himself whether, if I decide this case in a particular way am I necessarily agreeing or disagreeing with some critical aspect of the decision in the previous case? The areas for possible agreement or disagreement cannot be defined but they would include interpretation of policies, aesthetic judgments and assessment of need. Where there is disagreement then the inspector must weigh the previous decision and give his reasons for departure from it. These can on occasion be short, for example in the case of disagreement on aesthetics. On other occasions they may have to be elaborate.”