Guidance Note 7

1. This Guidance Note is issued to inform and guide those concerned in the planning, design and construction of house extensions and domestic garages. Matters dealt with include aspects of design and amenity control. This Note first lists the principles which are applied to house extensions and the erection of garages, and secondly, some practical guidance is given on the ways in which these principles are operated in relation to specific forms of development. It is not possible to cover all aspects of house extensions in this short note. Any proposal submitted for planning permission is required to be assessed on its own merits, although the Council will seek at all times to uphold the high standards promoted in this Note. This Guidance should be read in conjunction with the Guidance Note - Daylight and the Intervisibility of Windows.

2. The Council’s planning staff are available for discussion of proposals prior to submission of a planning application. Please make use of this service.

3. Buildings in Conservation Areas and buildings Listed as being of Special Architectural or Historic Interest will be subject to tighter controls on design and materials in order to maintain their particular character, in accordance with the Built Heritage Guidance Note.

General guidance on principles of design and amenity

4. The extension should generally reflect the design concept and detailing of the existing house e.g. Victorian villa, interwar bungalow, modern detached house, and should not detract from its appearance.

5. The extension should be of a scale which does not dominate the existing house and/or neighbouring properties.

6. The extension should take a form which does not adversely affect the visual amenity of the local street scene, or that of the surrounding area.

7. The general design and materials used for external finishes should generally be identical to or closely match those of the existing house. In Conservation Areas and Townscape Protection Areas materials should reflect those originally used and those which give the building its traditional appearance.

8. Direct overlooking, deprivation of daylight to adjacent windows, and excessive overshadowing of neighbouring gardens should be avoided. (See Guidance Note - Daylight and intervisibility of windows).

9. No extension other than a small porch should project forward of the front wall of the existing house or the line of buildings in a street.

10. A meaningful area of useable private (i.e. rear) garden ground should be retained in all house plots commensurate with the scale and amenity needs of the dwelling house, normally 30sqm per bedroom, or potential bedroom, of the house after the construction of any house extensions or domestic garages.

11. No extension should be built which precludes the possibility of on-site parking to the Council’s approved standards, and providing that such provision does not detract from the amenity and character of the house, gardens and street scene.

12. Pitched roofs should be used wherever possible and flat roofs should be avoided.

13. Windows and door openings should be aligned vertically and horizontally with existing door openings and windows.

14. Side extensions should be set back a meaningful distance from plot boundaries (i.e. a minimum of 900mm) in order to prevent the possibility of the creation of an undesirable terraced appearance in residential areas where this is not the norm.

Specific Guidance on House Extensions

15. The following guidance illustrates some practical examples of the ways in which the above principles are operated in relation to specific types of development and must be read in conjunction with the above principles. It is emphasised that the following is illustrative and that each application is judged on its merits in the light of the policies, principles and guidance contained in the Local Plan and this Guidance. Please note that conservatories are considered in the same way as any other house extension.

Should:

a) generally not breach well defined building lines along a street. Porches will be considered as an exception to this requirement and may project up to 1.5 metres from the main wall of the existing house (i.e. excluding the depth of bay windows etc…). If the proposed porch includes a toilet, it may be permitted up to 1.8m deep. All front

extensions shall be required to respect the amenity and character of the house and street scene.

b) where appropriate, be designed and positioned to be compatible with other extensions and porches on a semi-detached or terraced block.

c) be designed in keeping with existing dwellinghouse.

d) be aligned vertically and horizontally with existing door and window openings.

e) where a porch, include a significant area of glazing, normally not less than 33%.

f) meet the Council’s parking standards (see section 23).

Figure 1

Porch

17. Any extension

Should:

a) have a pitched (and hipped where appropriate) roof in the same style and materials as the existing building, particularly where the extension is visible to the public.

b) be set back a minimum of 250 mm from the front wall of the existing house (other than front extensions - see above) and below the main ridge line.

c) have a fully enclosed lower storey where two storeys in height and not incorporate pillars.

Should not:

d) unbalance the appearance of a semi-detached block by its scale or form.

e) extend more than 4.0 metres down a shared boundary to the rear of the house.

f) generally exceed the original ground floor area of the house by more than 50%. Where the plot size is large, e.g. larger detached properties or those on corner plots, or where extensions are ‘wrap-around’ (i.e. consist of side and rear extensions), areas greater than 50% will be considered on their merits, providing that the amenity and character of the house, the neighbouring properties and the surrounding area are not adversely affected.

g) generally cover more than 33% of the original private rear garden of the property (i.e. generally land behind the rear building line of the house).

h) where it is a two storey extension, generally be built to the rear of the house.

Figure 3

Extension to Rear of Detached Bungalow

18. Side extensions

a) Terracing

Side extension should not create (or potentially create) a terraced effect on a street scene. A two-storey extension onto a two-storey house, or a single storey extension onto a single storey house which approaches the property boundary is likely to risk this effect where there is potential for a neighbouring house to extend sideways to abut the joint boundary. In these circumstances there should normally be a gap of at least 900mm between the extension and the boundary to provide for this visual break in the building.

A terraced effect may also be avoided, for example:

1. where houses are stepped back a significant distance from one another;

2. on a corner plot;

3. where the remaining gap between the property boundary and neighbouring house is between 900mm and 2000mm (i.e. more than the minimum gap, but also sufficiently small as being unlikely to be developed for an extension).

b) Access

The extension should retain servicing access to the rear of the house, a minimum of 900mm in width, either:

i. around one side of the building,

ii. by another convenient route, for instance, a rear service lane, or

iii. through a garage/utility room, but not through a habitable room or kitchen.

Where the above cannot be achieved, appropriate provision should normally be made within the design of the extension for the enclosed storage of a wheelie bin.

19. Dormer Windows

Should:

a) be positioned significantly:

i. below the ridge line,

ii. within the hip of the roof ,and

iii. set back significantly from the wall head.

b) incorporate not less than 33% of glass on the face of the construction.

c) have windows aligned with openings in the lower storey.

d) have vertical faces finished in a material to match the existing roof.

Should not:

e) be on a side elevation, as this has a greater impact on the appearance of the building, and can impact more significantly on the privacy of neighbours (see below). Development of both front and side dormers should particularly be avoided, as this can give the appearance of the building being flat roofed. As an alternative, the use of the roof windows i.e. flush with the roof slope, would be encouraged.

f) dominate the existing roof by reason of its scale or the number of dormers.

g) be built on a two-storey building, unless dormer features are traditional to the original house style.

20. Privacy

All extensions to houses should ensure that good standards of privacy are maintained in and around the property. Extensions of any description should respect the privacy of neighbouring houses and private gardens, i.e. windows will generally not be permitted to overlook directly into neighbouring house windows or private gardens (especially areas close to the house where the highest standards of privacy will be expected).

Windows directly facing each other should be at least 18m apart. Exceptions to this rule may be:

a) for bathrooms (using obscure glazing), halls, landings, utility rooms or

b) where effective and acceptable screening is employed e.g. by fences or walls (note that this is only likely to be effective for ground floor windows and not on second storeys, and the requirement for screening should not generally require it to be more than 2m in height)

Provision and maintenance of screening may be required through a Section 75 Agreement.

Balconies, conservatories and raised decking/patios also raise the same privacy issues, and the above privacy criteria will also apply in these cases.

21. Raised Decking/Patios

Planning permission will be required for raised decking/patios within gardens, where the surface is raised more than 200mm from the original ground level. Decking/patios proposals will be assessed in terms of:

i. loss of privacy (in neighbouring houses and gardens),

ii. dominance, and

iii. loss of character or amenity of the area.

The adverse impact of decking/patios can, depending on individual circumstances, be minimised by providing effective and acceptable screening e.g. fences or walls which should not normally exceed 2 metres in height from the existing ground level. The scale of the fencing can itself have an adverse impact on the amenity of adjacent property by creating shading to windows or gardens, or dominating a garden, and this factor may justify refusing planning applications for raised decking/patios.

22. Daylight

(Reference is made to Guidance Note 3 - Daylight & intervisibility of windows).

Extensions should not result in a significant loss of daylight or sunlight to neighbouring properties and in particular the main apartment windows of neighbours’ houses (i.e. excluding bathrooms, halls, landings and small utility rooms).

SPECIFIC GUIDANCE ON GARAGES, CARPORTS AND PARKING

23. Garages and Carports

Should:

a) be built in a position that can be accessed safely.

b) preferably have a pitched roof when visible from the road.

c) be faced and roofed in materials to match the existing house or regularly maintained where built of timber.

d) generally be set back from the front wall of the existing house. In some cases, attached garages may be permitted in line with the front of a porch where this is not to the detriment of the street scene.

E ) generally have a minimum internal width of 2.7 metres in order to allow its effective use for the garaging of a standard family car.

Should not:

f) be used in connection with any business or commercial purpose.

g) exceed 4 metres in height.

Conversions of integral garages to living accommodation will be permitted where

h) the design of the alteration is in character with the original house.

i) parking arrangements are satisfactory, to the Council’s standards, at the appropriate rate for the house as so enlarged.

j) the provision of any additional parking does not detract from the character of the house, garden or street scene (see below).

24. Parking provision

Extending a house where additional bedrooms are created is likely to result in the house being capable of accommodating more people. This has an impact on the level (or potential level) of car ownership within the property. Additionally, where side extensions are built (or garages converted), existing parking areas may be lost from use. The Council will assess the adequacy and amenity of car parking provision in assessing any application, and will take into account particularly the following matters:

a) the number of parking spaces within the site should be appropriate for the size of house as enlarged (normal Council parking standards apply, i.e. currently the ‘Guidelines for Development, Roads’, although these standards will be reviewed during the life of this Local Plan),

b) parking should preferably be accommodated within an established driveway,

c) parking may be provided within a front garden, but only where it does not detract from the amenity of the area. As a guide:

(i) the parking should take up no more than 66% of the front garden area, and

(ii) the front garden should be designed and landscaped to an acceptable amenity standard (including avoiding the loss of important trees etc...). Note that particularly high standards will be applied in conservation areas etc... which could mean that front garden parking (other than single driveways) may be unacceptable,

d) the driveway/parking area should be no more than 10% gradient and the first 2 metres should be paved, and

e) road safety implications of creating additional driveways will be assessed.

Should you require any further information please do not hesitate to contact :

The Planning Office,

Development Quality Section,

The Triangle,

Kirkintilloch Road,

Bishopbriggs G64 2TR

Tel: 0141 578 8000

House Extensions and Garages

Back to Index