London Plan Policy 7.6 (Architecture) states that new buildings and structures should not cause unacceptable harm to the amenity of surrounding land and buildings, particularly residential buildings, in relation to privacy, overshadowing, wind and microclimate.
CS Policy 24 (Design) states that all development should seek to enrich and enhance Hackney’s built environment and create a sense of place and local distinctiveness that is attractive and accessible. It goes on to make clear that this will be achieved through (amongst other things) ensuring good and optimum arrangement of the site in terms of form, mass and scale, including usable amenity space where appropriate and addressing biodiversity matters.
Policy DM2 (Development and amenity) makes clear that development proposals should be appropriate to their location and should be designed to ensure that they will not result in significant adverse impacts on the amenity of occupiers and neighbours. It goes on to state that the individual and cumulative impacts of development proposals on amenity will be considered in considering their acceptability and that the consideration of the merits of development proposals will be balanced against the impact on amenity. It states that the amenity considerations include the impacts of developments on:
(i) Visual privacy and overlooking;
(ii) Overshadowing and outlook;
(iii) Sunlight and daylight, and artificial light, levels;
(iv) Vibration, noise, fumes and odour, and other forms of pollution;
(v) Microclimate conditions;
(vi) Safety of highway users.
The justifying text (3.3.3) to this policy makes clear that the design and layout of buildings must enable sufficient sunlight and daylight to penetrate into and between buildings and ensure that adjoining land or properties are protected from unacceptable overshadowing and refers to the use of BRE guidelines to determine acceptability.
The justifying text (3.3.5) to this policy notes that in the past, planning guidance for privacy has been concerned with achieving visual separation between dwellings by setting a minimum distance of 18-21 metres between facing homes. It goes on to state that these are still useful yardsticks for visual privacy, but adhering rigidly to these measures can limit the variety of urban space and housing types in the city and can sometimes unnecessarily restrict density. It further states that given the urban context of the Borough flexibility will be applied, particularly in consideration of the density of a scheme, and design measures incorporated to minimise overlooking and protect privacy.
The justifying text (3.3.6) to this policy states that all developments should consider local topography and the local microclimate in their design, and proposals must demonstrate they have addressed the potential impact on local conditions.
The Mayor’s Housing SPG notes that, in the past, planning guidance for the relationship between homes has set a minimum distance of 18 – 21m between habitable rooms. It goes on to acknowledge that these can still be useful yardsticks for visual privacy, but adhering rigidly to these measures can, amongst other things, limit the variety of urban spaces and can sometimes unnecessarily restrict density. The Mayor’s Housing SPG also includes the following guidance with respect to daylight and sunlight:
“1.3.45 … An appropriate degree of flexibility needs to be applied when using BRE guidelines to assess the daylight and sunlight impacts of new development on surrounding properties, as well as within new developments themselves. Guidelines should be applied sensitively to higher density development, especially in opportunity areas, town centres, large sites and accessible locations, where BRE advice suggests considering the use of alternative targets. This should take into account local circumstances; the need to optimise housing capacity; and scope for the character and form of an area to change over time.”
The potential scheme raises a number of amenity related issues.
Outlook and privacy
Any potential scheme would need to ensure that people living in existing homes in the three towers would be left with a satisfactory outlook from their windows and that their privacy is safeguarded. The southern façade of the three towers include single-aspect studio flats and it will be particularly challenging to ensure that people living here are left with an acceptable environment. The outlook and privacy of people living on the east side of Bethune Road also needs to be considered – although the proposed front-to-front relationships across the street is probably acceptable. The minimum distance between existing windows in the north and south facing flats in the existing buildings and any potential new flats is likely to be no more than 14 metres, assuming that any new block is kept to a minimum practical width i.e. single-aspect units with rear access corridor at no more that 12 metres wide.
Daylight and sunlight and overshadowing
There is the need for full detailed technical assessment of likely daylight and sunlight effects of the potential scheme. This should include Vertical Sky Component (VSC) and Average Daylight Factor (ADF) for all south and east facing windows on at least floors 1 to 6 of the three towers, together with Annual Probable Sunlight Hours (APSH) for all of these windows facing within 90 degrees of due south – including existing homes on the east side of Bethune Road. An assessment should also be made on overshadowing of existing amenity spaces that would be retained. The impact on the lower floor flats in the existing towers is a particular concern, most notably the single-aspect studio flats.
The introduction of new buildings between existing tall structures could have adverse effects on the local wind environment and this should be thoroughly tested (ideally by wind tunnel testing rather than Computational Fluid Dynamics (CFD)).
The potential scheme raises a number of amenity issues for the existing residents, including how the proposals would affect their outlook and privacy, daylight, sunlight and overshadowing, and the local wind micro-climate. None of these issues appear to have been considered during the selection of the site, and it is difficult to see how the existing residents would continue to enjoy an acceptable level of amenity in these respects given the potential scheme. The above issues need to be fully addressed at this stage and any planning application must be supported by assessments that demonstrates that existing residents would continue to enjoy an acceptable level of amenity.