The detailed guidance set out below is not exhaustive or definitive. Its purpose is to guide the design of new extensions/alterations to enable a better fit with the host building as well as minimise any visual intrusion on the street scene or character including avoiding harm to neighbours’ amenity. Variations to these guidelines may be acceptable where it can be demonstrated that no harm is caused to existing neighbouring amenity or to the character of the local area. Innovative and contemporary solutions that enhance a sense of scale, proportion and place are encouraged.
The Council will seek to ensure that rear extensions are of a suitable scale to remain subservient to the character and appearance of the main property and are sensitively designed. Particular care is needed if the property is located at the end of a terrace or is a corner property as an extension to the rear is likely to be visible from the street. The following guidance should be followed where relevant:
- Rear extensions should generally be subservient to the host property, however, for properties with a very large overall plot size larger extensions can sometimes be considered appropriate;
- Rear extensions should not have an overbearing impact or cause adjacent properties to be excessively overshadowed or enclosed. The bulk of the extension alongside the shared boundary should therefore be kept to a minimum;
- All rear extensions should comply with the 45 degree rule (see Appendix 3). This rule ensures there will not be an unacceptable loss of daylight to the neighbouring properties;
- Rear extensions must not overhang neighbouring properties and should not replace the boundary wall/fence (unless the adjacent property has an existing extension themselves and the loss of the wall is required for better maintenance purposes);
- In the majority of cases rear extensions (both single and two storey) should not extend beyond the main side walls of the building (including all projections/wings);
- The ridge of the pitched roof of a single storey rear extension should sit lower than the cill of the first floor windows;
- Flat roofs can be suitable for single storey rear extensions particularly where they integrate well with the host building;
- Two storey rear extensions should generally have a roof form which reflects that of the host building. A pitched roof extension should normally be set lower than the main ridge of the roof;
- Where side-facing windows are required for light, they should generally be high level, permanently fixed shut or obscurely glazed to prevent the overlooking of neighbouring properties.
- Materials used in the extension should be sympathetic to the character of the area and the property being extended;
- Rear extensions should ensure that a suitable amount of rear garden/amenity area is retained.
Lean-to rear extension: Archangels Architects, Brighton & Hove
Two storey rear extension: LW Architects, Brighton & Hove
Spacing between buildings helps to define the character of an area. Side extensions therefore should ensure that rhythm of spacing between buildings is maintained in order to minimise the potential ‘terracing’ effect. In terms of semi-detached and terraced properties, the proposed extension should avoid unbalancing the attached properties.
- The following guidance should be followed where relevant: Side extensions should be set back from the front elevation appropriately in order to ensure a subordinate appearance (and set down from the roof ridge in the case of a two storey side extension). The setback and setdown helps to avoid the terracing effect and enables the extension to be read as subservient to the original building;
- Side extensions should complement the original property. The width of a side extension should respect the width of the original property and the overall plot size in which it is located to avoid it appearing over-extended;
- The design, detailing, and materials used in the extension, including window position/pattern, sizes, proportions, style and method of opening, should complement those of the main building;
- The incorporation of a roof form which matches the character and materials of the host property and surrounding area will often be considered to be most acceptable;
- The residential amenity of adjoining residents will be a particularly important consideration when assessing side extensions. Flank windows should not allow overlooking and may have to be permanently fixed shut and fitted with obscure glazing (or obscure glazed blocks) and kept to a minimum. Windows, roof eaves, gutters or downpipes should be avoided on party walls for planning purposes so that extensions do not intrude on neighbouring properties or restrict their future extension;
- For detached properties appropriate set-in should be provided between the site boundary and the extension retaining a proportionate amount of space. Where the property is located in a more spacious plot, a greater separation may be more appropriate to complement the character of the area;
- Infill extensions should not have an overbearing impact or cause adjacent properties to be excessively overshadowed or enclosed. The bulk of the extension alongside the shared boundary should therefore be kept to a minimum, and as close to 2 m in height as reasonably possible on the boundary;
- Infill extensions must not overhang neighbouring properties and should not replace the boundary wall/fence (unless the adjacent property has an existing extension themselves and the loss of the wall is required for better maintenance purposes);
- Corner properties should ensure an active and attractive street frontage. Corner plot side extensions should also respect the building lines to both streets, and be set within existing boundary treatments.
Front extensions (Including porches)
Extensions to the front of buildings will normally be highly visible in the streetscene therefore particular care should be taken to ensure they do not detract from the appearance of the property, or the general character of the street. Particular regard should be given to the materials, detailing, prevailing building lines and fenestration of front extensions to ensure they relate well to the original building and the streetscene.
- The following guidance should be followed where relevant: All front extensions should respect the building line to the street, particularly where a strongly defined building line forms an important character of the area;
- A front extension should not dominate the existing façade or any important architectural feature that already exists in the original building;
- The roof pitch of the extension should complement the pitch of the original building so that the extension blends with the character of the building.
- A small porch is generally acceptable on most building types provided it does not compete with other architectural features on the building and is of the right scale and proportion;
- Even an extension that is subservient in size can add an incongruous shape or form that is out of character with the front elevation of the property or the surrounding area. Careful attention should be given to the style as well as the size and proportion of any front extension.
An example of a two storey front extension
An example of a discreet porch extension
The rhythm and continuity of the rooflines to buildings are often a key visible element within a streetscene therefore any poorly designed or excessively bulky additions can have a significantly harmful impact on both the appearance of the property and the continuity of a streetscape. In addition, consider the following guidance:
- Extensions involving roof alterations should ensure that they would not result in an imbalance between the semi-detached pair or in a small terrace. A well-designed alteration that returns symmetry to the pair may be acceptable
- Additional storeys or raised roofs may be permitted on detached properties where they respect the scale, continuity, roofline and general appearance of the streetscene, including its topography;
- Roof extensions that alter the basic shape of the roof are likely to have an impact on the streetscene. Such alterations should reflect the character of roof forms in the surrounding area.
A dormer is a window that is typically set vertically on a sloping roof. The dormer has its own roof, which may be flat, arched, hipped, gabled, or ornamented. Dormers can add elegance and appeal to the property, but they can also end up making the property look out of proportion, so the design should be carefully considered in line with following guidance:
- Dormer extensions are expected to avoid appearing unduly bulky or visually harmful, and should not materially disrupt the rhythm and continuity of the prevailing roofline in the area;
- The most appropriate roof design of a dormer (gabled/hipped/flat/eyebrow) will vary depending upon the character of the host property and surrounding area;
- Where a terrace or group was built with dormers, these original features should not be removed or altered. Where a terrace or group was originally designed without dormers, but over the years a majority of the buildings now have them, new dormers may be acceptable provided their scale, design and positioning is sympathetic to the continuity of the terrace/group;
- Generally, the cladding, glazing, framing and any ornamentation on the dormer window should match the existing property.
Rear and side dormer windows
Dormer windows on the rear roof slope will normally have limited or no impact on the streetscene, however, they should clearly be a subordinate addition to the roof set appropriately in the roof space to avoid looking disproportionate to the property.
As a rule rear dormers should be appropriately set in from the side, set down from the ridge and set up from the eaves so as not to appear as an additional storey or appear “top heavy”. In addition, further consideration should be given to ensure that:
- Rear dormer windows do not appear above the ridge line of the dwelling;
- Rear dormer windows are generally well-proportioned to the roof space and do not appear overly dominant. Where two or more dormers are proposed they should be evenly aligned and spaced within the roofspace;
- Rear dormer windows should normally align with the windows below, however, in certain cases it may be preferable for dormers to be positioned on the centre line of the building;
- Materials of the window frames, roofing and cladding should match or relate well to those of the existing roof or the property;
- Well-designed side dormers are acceptable where they do not compromise the character of the building or the street and/or the privacy of a neighbouring property.
Front dormer windows
Dormer windows on the front roof slope will have a greater impact on the streetscene. Front dormer windows should be sensitively designed to respond to their prominent setting. Depending on the character of the street, front dormers may be acceptable, and where acceptable they will generally be limited to a single dormer extension. Exception may be made in some areas of the City where front dormer windows are a common feature and where the size of the property can comfortably accommodate more than one dormer.
Front dormers should be:
- Set-back appropriately from the eaves of the main building;
- Set-down down appropriately from the ridge;
- Designed with a roof and materials to complement the host property.
Normally it is expected that dormer positioning will align well with the windows below. As in the case of rear dormers in certain cases it may be preferable for dormers to be positioned on the centre line of the building or the centre line of the space between the windows below.
Balconies and roof terraces
Balconies and roof terraces can provide valuable and welcome amenity space for properties; however, in many cases they can significantly affect a neighbour’s privacy and create a sense of overlooking, particularly if they are located where it is possible to look into gardens or windows that previously enjoyed privacy. The presence of balconies and roof terraces may also result in noise disturbance, particularly to nearby windows, and can also be harmful to the appearance of a building. Careful consideration needs to be given to the location and design of a balcony or a terrace including any associated balustrades
Balconies and roof terraces at the front and rear of the building including any other prominent locations visible from the street are only acceptable where they do not harm the appearance of the building and streetscene.
The urban character of certain parts of Brighton and Hove means some properties already overlook one another. Balconies and roof terraces that create new overlooking or make existing situations much worse are unlikely to be approved. In such cases screening can provide the required privacy to all parties but their detailing and size must also be appropriate to the character of the building and area.
The construction of outbuildings in rear gardens and other undeveloped areas can often have an impact upon the amenity, biodiversity and character of an area.
The siting, location, scale, materials and design of the outbuilding should have a minimal visual impact on, and be comfortably accommodated within the host garden. The maximum size of the outbuilding (or number of outbuildings) will usually be determined by the location and the size of the garden area.
- Irrespective of the size of the outbuilding proposed, the open character and outlook of the rear garden should be maintained;
- Outbuildings will normally be restricted to a single-storey so that they do not harm the amenity of neighbouring homes and gardens. The maximum permitted height will normally be determined by the impact on residential amenity and the proximity of the outbuilding to the neighbouring boundaries, on both sides and to the rear.
- The intended use of the outbuilding will be a consideration so as to ensure the development respects the use and character of an area.
New and replacement windows
The character of a property can be enhanced by the alteration or addition of new windows or doors that align with the style and character of the original. Good quality window design and placement can contribute to the general appearance of buildings, help maintain the rhythm of the streetscene, particularly on large blocks of flats and more traditional building forms where the continuity of fenestration is a key element. New and replacement windows should:
- Complement the appearance and character of an existing building / terrace, closely matching original details, frame styles and materials where possible.
- Align well with the existing windows in terms of size, design, rhythm and pattern of openings in terms of window positioning, and orientation;
In most cases windows positioned to match the symmetry of those in the existing building help maintain the aesthetics and character of the building.
The size, design and siting of rooflights should not significantly change the appearance of the building externally and should not introduce detrimental visual elements into the streetscene.
- Roof lights (particularly to street elevations) should be kept as few as possible and should relate well to the scale and proportions of the elevation below, including aligning with windows or centering on the spaces between them where appropriate;
- Where two or more rooflights are proposed they should be evenly aligned and spaced within the roofspace;
Irregular rooflight sizes and positioning should be avoided, and in particular will be resisted on street elevations.
Boundary walls, hedges and fences
Garden walls, fences, railings and hedges are all important elements in the streetscene. They provide the distinction between the private space and the public space of the pavement and street.
Differing boundary treatments along a street can result in a cluttered, disordered appearance. This effect is particularly noticeable in streets of terraced or semi-detached houses. Alteration of front boundary walls and fences will need to:
- Be constructed from materials in sympathy with the building or surrounding area;
- Respect the height of other enclosures in the street so to not appear unduly conspicuous and out of character;
- Consider well maintained planting as an attractive and green solution for a new boundary; Safeguard pedestrian and vehicular safety.
The design and height of boundary walls (including pillars), railings and gates should relate to the character of the street/surrounding area, particularly if of a uniform character. Details such as railed sections and pillars can reduce the visual impact of a high wall. The removal of a front boundary wall or hedge and the development of the front garden into a forecourt for parking will be resisted where it would have an adverse impact on visual amenity or the character of the streetscene.
Satellite dishes, cables, ducts and pipework
Satellite dishes and aerials including cables, ducts and pipeworks can add visual clutter and detract from the appearance of a building and streetscene if located in a prominently visible position. It is therefore important to ensure that:
- Satellite dishes and aerials are sited in the most unobtrusive position possible and not be located on walls, chimneys or roofs visible from the street;
- The number of dishes should be reduced where possible to avoid the visual clutter;
All cables, ducts and pipework should run internally or up the rear wall in discrete positions and be coloured/painted to match the background wall. Flues, ventilation units and other services that appear as 'add-on' elements will not normally be accepted in elevations visible from streets.