Appeal 3332066

The appeal is dismissed.

A revised version of the National Planning Policy Framework was published in December 2023, but there are no material changes relevant to the substance of the appeal.

The main issues are the effect of the appeal proposal upon the character and appearance of the area; and upon surface water flooding.

The appeal site comprises a two storey end of terrace house that benefits from a quite substantial two storey side extension with a single storey extension that wraps around it to the front and side/rear. The proposed first floor addition would build over these, including the south west elevation which tapers at approximately 45° along the boundary shared with [address].

The proposal in its entirety would add significant bulk to the host dwelling, failing to appear subservient to it and dramatically unbalancing the terrace of which it forms part.

Policy DMD3 of the Sites and Policies Planning Policies Maps July 2014 (SPP) requires alterations or extensions to buildings to meet a number of criteria, including that they respect and complement the design and detailing of the original building, as well as respecting the form, scale, bulk and proportions of it.

The proposal would subsume the existing dwelling, such that it would be largely unrecognisable and would also run counter to the existing simple architecture found within the street. Therefore, whilst the proposed additions may incorporate materials, design and detailing of the original building, its overall scale and form would be significantly affected in a detrimental manner. Further, due to its triangular shape which tapers towards the rear, I consider that the plot would be unduly dominated by the appeal scheme and whilst there may be other examples of large side and rear additions of various forms which extend deep into plot depths within the area, each case must be assessed on its own merits.

Therefore in addition to being in conflict with the first two criteria of SPP Policy DMD3 as highlighted above, I consider that the proposal would fail to complement the character and appearance of the wider setting with a roof form that would not be of an appropriate size, type or form for the existing building, being unduly dominant and failing to respect the prevailing positive characteristics of the area. The proposal would also conflict with SPP Policy DMD2, Policy CS14 of the Local Development Framework Core Planning Strategy adopted July 2011 and Policy D3 of the London Plan 2021 in that development proposals should enhance local context by delivering buildings that positively respond to local distinctiveness through their layout, orientation, scale and appearance whilst improving Merton’s overall design standard.

It is agreed between both parties that the site is within [name] 1 with a low probability of fluvial flooding. The Council, however, states that the site is situated in an area at risk of surface water flooding and in a critical drainage area, but has not substantiated this. It is not entirely clear if the proposal would increase risk to flooding in the locality, however, bearing in mind that there would be no increase in footprint of the proposed development, whilst the nature of roof construction would change as a result of the proposal, ultimately the level of surface water run-off from the appeal dwelling as proposed to be extended would unlikely be materially greater than the existing situation. [name] had been so minded to have allowed the appeal, then an appropriately worded condition requiring sustainable urban drainage measures could have been imposed.