Effects on neighbours

Any extension should not detract from the amenities of the adjoining property with regard to loss of privacy, loss of sunlight and daylight or by unduly harming their outlook.

Consultation
Before you apply for planning permission it is a good idea to talk to your neighbours about your proposed extension so that they are aware of your plans.

Privacy
The windows of any extension should not look directly or obliquely into those of an adjacent property. Neither should there be any overlooking of adjoining rear gardens to an unreasonable level as shown in Figure 7A. This should be achieved through careful design of the extension's internal layout. The retention of mature trees and hedges may sometimes help prevent overlooking. It is particularly important to ensure that the most private area of the garden is protected from overlooking, i.e.. that part nearest the house; see Figure 7B. Fixed non-opening windows in obscure glazing or high level windows (i.e.. those with a cill height of not less than 1.8m from the internal finished floor level) may be permissible in flank walls where no alternative is available. Additional features such as balconies and dormer windows that result in overlooking will not be acceptable.



Figure 7 A shows an unreasonable level of overlooking whereas the shaded area in B has retained its privacy.

Outlook
An extension's projection can seriously affect the outlook or light provision to an adjoining owner's nearest habitable room. Two storey rear extensions to semi-detached and terraced dwellings are usually very prominent in views from adjoining dwellings and will dominate outward views from adjoining ground floor windows, appearing excessively large and dominant.



Figure 8 A detrimental impact upon a neighbour's outlook caused by a badly sited extension

Daylight and Sunlight
Care should be taken not to significantly reduce the daylight and sunlight enjoyed by adjoining dwellings. Figure 9 shows the effect of shadow at near midsummer in the case of a two storey extension constructed on the rear of an east facing house. The daylight enjoyed in the ground floor room of the adjoining dwelling will also be greatly reduced.


Figure 9 An unacceptable example of overshadowing

Projections will be determined as shown in figure 10. Extensions should project no further than a line drawn at 60° (for single storey) or 45° (for first floor and two storey extensions) from the mid point of the window of the nearest habitable room on the ground floor of adjacent properties. Habitable rooms include kitchens, living rooms and bedrooms but exclude bathrooms, toilets, halls, landings and store rooms.



Figure 10 Code for house extensions projection

Conservatories
The principles that apply to house extensions also apply to conservatories. Ensure that the materials and design of the conservatory harmonise with the rest of the house so that it will not look out of place.


Figure 11 A well designed conservatory