Appeal 3326593

The appeal is dismissed.

The development is already in place. I have therefore dealt with the appeal on the basis of its retention.

The main issue is the effect of the development on the character and appearance of the host property and the area, including whether it preserves or enhances the character or appearance of the Rickmansworth Conservation Area (‘the RCA’).

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 states that, in respect of development affecting conservation areas, special attention shall be paid to the desirability of preserving or enhancing their character or appearance. The National Planning Policy Framework (December 2023) (‘Framework’) sets out that great weight should be given to the conservation of designated heritage assets, such as conservation areas, and that harm to their significance requires clear and convincing justification.

Policy CP12 of the [name] 2011 (‘TRCS’) sets out that development should conserve and enhance heritage assets. Policy DM3 of the Three Rivers Development Management Policies Local Development Document 2013 (‘TRDMP’) states that development will only be permitted in conservation areas if it preserves or enhances their character or appearance.

The RCA encompasses the historic core of the town, and surrounding areas such as the mainly residential roads either side of [address]. [address] is one of those, with predominantly Victorian and early twentieth century housing. It is not covered by the Rickmansworth Conservation Area Appraisal and Character Assessment 1993, but I observed that the properties here are two storeys high, terraced and semi-detached, and laid out in long straight rows, close to the highway. They are generally finished in brick and render, and grouped with others of a similar style. These characteristics give the area an attractive sense of consistency and cohesion.

To the rear, although the original two storey form of the houses is still clearly apparent, many have been extended or altered. As illustrated by the photographs in the appellant’s statement, some in this terrace, including No 95, have dormer windows, as do some others on this side of [address]. To a degree, rear dormers now form part of its established character.

However, the dormer at No 97 is larger than the one it replaced. It is also larger than the neighbouring dormer at No 95, and compared to many of the others on this stretch of the road. Whilst it is set down from the host’s ridge, it is only marginally set in from the building’s eaves, and very slightly from the party walls. Its scale and rectilinear form dominate the host’s formerly sloping roof, and give the building an anomalous, top-heavy, three storey bulk.

Moreover, unlike nearby examples, this dormer has virtually full height glazing, which does not reflect the proportions, colour, or style of the windows in the floor beneath. Although there are smaller grey framed windows at No 61, considered along with the scheme’s bulk and scale, this adds to its incongruous appearance.

I have considered an appeal decision at No 119 (APP/P1940/D/18/3213953). Unlike that proposal, this one is not visible in the [address] streetscene. However, it can be seen from gardens and other land to the rear, including looking into the RCA from the nearby allotments, and to a lesser degree, in distant views between vegetation from [address].

Having regard to Schedule 2, Part 1 of the Town and Country Planning (General Permitted Development) (England) Order 2015, dormers similar to this one may be permitted development elsewhere, but not within a conservation area such as this. Those permitted development rights do not therefore affect the outcome of this appeal.

As TRDMP Policy DM1 concerns new residential development and the subdivision of dwellings, it is of little relevance to this scheme. However, in harming this typical part of the RCA, the scheme fails to preserve or enhance the character and appearance of the RCA as a whole, and it thus conflicts with TRCS Policy CP12 and TRDMP Policy DM3.

It also fails to comply with the advice at Appendix 2 of the TRDMP that dormers should always be subordinate to the main roof; set in from either end; set back from the plane of the wall; and that their form should respect the character of the house if possible.

The harm to this designated heritage asset is a matter to which I attribute great weight. However, having regard to the presence of other nearby dormers, and in the language of the Framework, the harm caused to it is ‘less than substantial’. I have therefore weighed it against the public benefits of the proposal.

In its favour, the scheme provides existing and future residents with more habitable space, and therefore improved living conditions. However, that benefit is largely private, relating to the enjoyment of the house by its occupants. Therefore, I find no public benefits that outweigh the harm that I have identified, and the scheme also conflicts with the Framework.

For these reasons, and having regard to all other matters raised, the appeal is dismissed.