CONTEXT AND JUSTIFICATION
The building of extensions and making other alterations to dwellings should be viewed as adapting and prolonging their life but the effect any house extension or alteration has on the property, on neighbouring properties and the surrounding area, must be carefully considered. A development that is out of scale or out of sympathy with its surroundings can spoil the appearance of the whole street. There may be a limit beyond which any property cannot be satisfactorily extended, for example, for reasons of privacy and daylighting.
The policy should be read in conjunction with policies HER 1 – HER 3.
GENERAL PRINCIPLES
Planning applications for extensions and alterations will be judged firstly against the following general principles:
1 Design and Materials;
2 Rear Access;
3 Usable Private Garden Space;
4 Privacy and Overlooking; and
5 Daylighting.
Applications will then be judged against the policies for the particular type of development proposed, namely:
6 Dormers;
7 Front Extensions;
8 Single-storey Rear Extensions;
9 Single-storey Side Extensions and Integral Garages;
10 Conversion of Garages to Living Accommodation;
11 Two-storey Extensions;
12 Free-standing Garages;
13 Conservatories;
14 Balconies, Raised Patios and Sun Decks;
15 Extensions to Flats; and
16 Fences and Walls.
POLICY
Extensions and alterations to properties should be very carefully designed to ensure that they do not over-dominate the original building or detract from the general character of the area within which the building to be extended or altered is situated. It is not, however, the intention to stifle or dismiss innovative design which could complement the original design. The aim is to encourage the best possible design solutions to any building alteration or development.
Extensions to listed buildings and properties within conservation areas should respect the character of the listed building and/or conservation area and not over-dominate the original property by over-large extensions.
1. DESIGN AND MATERIALS
Extensions and other alterations to dwellings should be designed as an integral part of the property. They should not dominate the existing building, or be designed in isolation solely to fit in a required amount of extra accommodation. They should reflect the character of the original building (see policy DES 3: Building Design and Materials).
The extension should be of a scale that does not dominate the existing property or its neighbours. Side extensions should be subsidiary in appearance to the main house.
The extension should reflect the design of the dwelling and the character of the neighbourhood and should not detract from the appearance of the dwellings or the street scene.
External materials should be similar to the existing property.
The windows and doors in the extension should match those of the existing property in shape and proportion.
2. REAR ACCESS
Many houses have access around the side of the property. This allows domestic and garden refuse to be carried to the collection point at either the front or the rear area of the property. Extensions to garages are unsatisfactory where they would block the path around the side of the house, thereby forcing refuse and garden equipment to be carried through the house or refuse bins to be stored in the front garden. In addition, two storey side extensions built right up to the side boundary can radically alter the character of a street or result in a terracing effect. Extensions built right up to the boundary mean that they cannot usually be built or maintained without entering neighbouring land and sometimes result in neighbour disputes or unsatisfactory finishing treatment to side walls. Often they also result in the removal of trees and hedges that contribute to the character of the area. Extensions will not, therefore, be permitted to be built up to a common boundary blocking off the only route around the house. Exceptions may be made where a route will be maintained through the extension via a garage or utility room on the ground floor, or where the extension would abut an extension in the neighbouring rear garden. All extensions, garages, etc should be set back from the side property boundary by at least 0.9 metres.
3. USEABLE PRIVATE GARDEN SPACE
Extending over a large area of the garden, particularly the useable private garden space, can result in over-development of the site. Any extension should leave a reasonable garden area for normal domestic activities, compatible with the overall size of the plot. Meeting the minimum distance guidelines between rooms (see the following section on Privacy and Overlooking) will allow some protection of garden ground.
For the purpose of this policy, useable private garden space will be taken as land that is under the exclusive control of the applicant and within the curtilage of the dwelling house. It only includes ground that has been adequately screened, usually to the rear and side of the property, and excludes the driveway. Note that the front garden is rarely private. Original useable space means the useable space available before the erection of any extensions, garages etc.
A minimum of 66% of the original useable private garden space should be retained in all house plots after extensions, garages, and outbuildings etc. have been built (see policy HER 3: Design Standards for Listed Buildings and Properties in Conservation Areas).
4. PRIVACY AND OVERLOOKING
Householders can reasonably expect to enjoy a level of privacy in their homes and not to be overlooked directly in their private gardens by the windows of another property. To control the potential problem of privacy, minimum distances will be set for windows which face adjoining properties. The minimum acceptable distance between windows of rooms which are directly facing each other will be 18 metres. If the windows are at an angle to each other, the minimum distance can be reduced. Room windows that are directly facing each other should be at least 9 metres from the site boundary and should not directly overlook the private areas of a neighbouring garden. The minimum distances do not apply to bathrooms (which usually have obscured glazing), halls and landings.
The minimum distance guidelines may be relaxed for ground floor windows where effective permanent screening is employed, e.g. walls and fences, to protect privacy or prevent overlooking. This cannot usually be done in the case of 2 storey rear extensions. Care must be taken to ensure that the screening used is sympathetic to the surroundings in terms of scale and material.
Balconies, dormer windows and conservatories all have the potential to cause overlooking problems. They will, therefore, be considered as rooms in terms of privacy. Dormer windows may be acceptable below the minimum distance if they light bathrooms, halls and landings (see later sections on dormers, conservatories and balconies). Minimum distance requirements do not apply to rooflights as it is difficult to achieve a view other than of the sky.
To maintain an acceptable level of privacy for neighbours, the window to window distance between all rooms, excepting bathrooms, halls and landings should be at least 18 metres. This may be reduced if the windows are at an angle. This minimum distance may also be reduced for ground floor windows if effective permanent screening is employed, provided this screening would not detract from residential amenity.
Side facing windows, and windows looking on to private garden ground, not in the sole ownership of the applicant, will be acceptable only where they do not cause any loss of privacy to neighbouring dwellings or private gardens.
5. DAYLIGHTING
Some building extensions will cast a shadow that may reduce a neighbour’s daylight and adversely affect their amenity. In terms of daylighting, the effect on all rooms, apart from halls, landings, bathrooms and small utility rooms, will be considered. To protect the amount of daylight in a neighbour’s rooms, it is advisable to keep extensions as far as possible from the boundary with adjacent properties. It should be noted that the loss of a view or outlook as a result of an extension is not considered a material planning matter.
Permission will be refused if a neighbouring property would suffer significant loss of daylight to any room (with the exception of bathrooms, halls, landings and small utility rooms) from the construction of an extension.
Note: A Building Research Establishment (BRE) document - Site Planning for Daylight and Sunlight: A Guide to Good Practice’, (PJ Littlefair 1991), sets out numerical standards to help ensure enough daylight is achieved in or between buildings for good interior and exterior conditions. These standards will be used by the Council in determining the effect on daylighting (see policy RES 2: Residential Site Layouts).
Guidance on Specific Types of Development
The policies for each of the following development types shall apply in addition to the above policies.
6. DORMERS
The formation of new dormers can have a major impact on the appearance of the property and the streetscene because of their prominence. To avoid appearing overdominant, a dormer should not in itself form the major part of the upstairs room. It should simply provide extra headroom and daylight. Dormers placed to the rear of the property with rooflights, if required, to the front would be preferable to front dormers.
Dormers on the side of hipped roofs can cause problems of overlooking, as they generally look directly on to the roofs of neighbouring properties or into neighbouring gardens. This would infringe the privacy of neighbours. Dormers on hipped roofs also have a greater impact on the appearance of the house than rear or front dormers.
Dormers should not be overdominant in relation to the existing scale of the property and not give the appearance of a flat roof.
Dormers should:
(i) be well below the ridgeline of the roof;
(ii) be drawn well back from the eaves;
(iii) not extend the full width of the roof (two small dormers on the same elevation would be preferable to one large dormer);
(iv) not extend right up to the gable end;
(v) relate to windows and doors below in character, proportion and alignment;
(vi) be finished to match the materials of the existing roof; and
(vii) have a front face predominantly glazed.
Permission for dormers on the side of hipped roofs will only be granted where they comply with the relevant parts of the above policy and do not detract from the residential amenity of neighbouring properties as a result of overlooking.
7. FRONT EXTENSIONS
Apart from small porches, extensions should not be built forward of the main wall of the house. Front Extensions should be of a size, scale and design compatible with the existing house, neighbouring properties and the streetscene.
Front Extensions:
(i) not exceed three square metres floor area and project no more than 1.5 metres from the existing property;
(ii) be aligned vertically and horizontally with existing door and window openings where possible; and
(iii) not exceed one-storey in height.
8. SINGLE-STOREY REAR EXTENSIONS
Although single-storey rear extensions have less impact than other types of extension, flat roofed additions can detract from the appearance of the existing building. For larger extensions a pitched roof (including mono-pitched) will be required.
Single-storey rear extensions should have a pitched roof (including mono-pitched), although a flat roof may be acceptable for small single-storey rear extensions less than six square metres in area and two metres in depth.
9. SINGLE-STOREY SIDE EXTENSIONS AND INTEGRAL GARAGES
Single-storey side extensions are more prominent than extensions to the rear of properties and ideally should be set back from the front wall of the property by a minimum of one metre. An exception may be made to this requirement where it can be shown that internal access to the extension would be difficult to provide. All extensions should have a pitched roof, which could be either mono-pitched or double-pitched, as appropriate.
Side extensions, which come right up to the front of the house should not protrude in front of the building line. For the purposes of this policy, the building line does not include elements such as the front of any porches, canopies or bay windows.
Single-storey side extensions and integral garages should:
(i) have a pitched roof; and
(ii) preferably be set back from the front of the building line by a minimum of one metre but, at the very least, not protrude in front of the building line.
10. CONVERSION OF GARAGES TO LIVING ACCOMMODATION
The conversion of garages to provide additional living accommodation can result in parking congestion on the street as well as resulting in rooms with little privacy as they look directly on to a driveway or a lane, in the case of a mews cottage. Any application to convert a garage to living accommodation will be discouraged, unless alternative garage arrangements are provided within the curtilage of the dwellinghouse. Planning permission is only required for these conversions where permitted development rights have been removed from the properties concerned.
Where an application is submitted to convert a garage to living accommodation, it will be assessed against:
(i) the car parking provision for the property;
(ii) the overall parking provision in the immediate area;
(iii) the details of the external alterations; and
(iv) the possibility of erecting a replacement garage within the curtilage of the dwellinghouse.
11. TWO-STOREY EXTENSIONS
Two-storey rear extensions, in particular, can cause overlooking problems and loss of daylight to neighbouring properties. They will therefore be resisted unless they clearly meet all the requirements of policies on privacy, overlooking and daylighting and comply with the other general principles stipulated earlier (see policy Res 2).
To ensure that two-storey side extensions remain subsidiary in appearance to the main house, they should be set back a minimum of 1.5 metres from the building line. The requirement to pull all extensions a minimum of 0.9 metres in from the side boundary (see 2. Rear Access) is also an important factor in avoiding any terracing effect. Exceptions may be made for extensions to houses where an unbroken massing, such as the creation of a terrace, could not arise in the future.
Applications for the erection of a second storey on top of an existing single-storey extension will be considered in the same way as applications for two-storey extensions.
Two-storey extensions should have a pitched roof (the roof style should tie in with and match the existing roof) and avoid the creation of a terracing effect by:
(i) in elevational terms, carrying through the line of the eaves of the existing house;
(ii) being set back a minimum of 1.5 metres from the building line of the house; and
(iii) having the ridge line of the extension lower than the ridge of the roof on the original house.
12. FREE-STANDING GARAGES
A garage should be in a position where it can be accessed safely. It should be set a minimum of six metres back from the rear edge of the public footway, so that a car can be parked in the driveway without jutting out onto the pavement. A garage should be designed to reflect the character of the property and neighbourhood and should have a pitched roof, unless it is well screened from public view. It should also not extend in front of the established building line, which does not include elements such as the front of porches, canopies or bay windows.
Domestic garages should:
(i) be set a minimum of six metres back from the rear edge of the public footway;
(ii) be designed to reflect the materials of the property and neighbourhood;
(iii) have a pitched roof, unless it is well screened from public view; and
(iv) not extend in front of the established building line.
13. CONSERVATORIES
As conservatories are, in essence, living rooms with glass walls, they can cause problems of privacy and overlooking (see 4. Privacy and Overlooking), particularly when erected on terraced or semi-detached properties. Only ground floor conservatories will be permitted, although conservatories with deep underbuildings caused by steeply sloping ground may be permitted. Any difference in level between the house and the garden should be taken up by a staircase within the conservatory (see policy HER 3).
On all conservatories the materials used for the base walls and fire walls should match the materials of the house.
Conservatories should:
(i) have base walls and fire walls in materials to match the house; and
(ii) be at ground floor level only, except where deep underbuildings are required to cope with steeply sloping ground.
14. BALCONIES, RAISED PATIOS AND SUN DECKS
As balconies and sun decks, particularly above first floor level, offer direct panoramic views over adjoining properties and gardens, the residential amenity of neighbours can be severely affected. Applications will be assessed in terms of privacy and overlooking. To reduce overlooking, balconies can, for example, be screened along the sides.
Balconies, raised patios and sun decks will only be granted permission where there is no adverse effect on neighbouring properties because of overlooking of private amenity space e.g. rear gardens.
15. EXTENSIONS TO FLATS
Extensions to flats such as 4-in-a-blocks and subdivided villas pose particular difficulties because of the proximity of properties and the complexity of land ownership in subdivided properties. Although flat dwellers have less privacy in their rear garden than house dwellers, as they are directly overlooked by their immediate neighbours, this situation should not be worsened by a proposed extension. Flatted properties usually have paths and areas of ground in common ownership and these areas should not be built over. Extensions should not have any windows or doors immediately adjacent to amenity areas in common ownership. All applications should comply with the policies on Usable Private Garden Space (3), Privacy and Overlooking (4) and Daylighting (5).
In common with the above policies on single and 2 storey house extensions, extensions to flats should have a pitched roof, although the shared ownership of the main wall of the property may make this difficult to achieve.
Where an extension is proposed to a ground floor flat, there is often concern about gaining access to upper floor windows for cleaning or repair. While the access to upper floor windows is not a material planning consideration, in the interests of good neighbour relations, the applicant is strongly advised to obtain the agreement of all common owners prior to commencing any works on site.
Extensions to flats should:
(i) not be built on land in common ownership;
(ii) preferably have a pitched roof; and
(iii) not have windows or doors immediately adjacent to common amenity areas.
16. FENCES AND WALLS
Fences and walls, particularly in front gardens, can have a significant effect on the appearance of the property and streetscene. Where erected beside driveways or on the corner of a street, they can also have an impact on sightlines and traffic safety. Both the visual and road safety aspects of a wall or fence will be assessed when an application is being considered.
In front gardens, where privacy is less of a consideration, walls and fences should not exceed one metre in height, except in areas where higher boundaries are the established pattern. In rear gardens, where a level of privacy can be expected, two metre high walls and fences may be permitted. Materials should always complement the character of the property and the neighbourhood.
Fences and walls should:
(i) not exceed one metre in front gardens and two metres in rear gardens, unless higher walls/fences are the established pattern; and
(ii) be erected in materials to complement the character of the property and neighbourhood.