Appendix 1 – Design Criteria

Appendix 1 - Design Criteria Buildings, streets and spaces should be of the highest quality. In addition to the policies of the Local Plan, development proposals should satisfy the following more detailed criteria to ensure that new development creates a positive sense of place, does not lead to a gradual deterioration in the quality of the built environment, and that landscaping, the need for privacy and amenity space and the creation of identity in new development are taken into account. It is important to note that whilst a development may be in accordance with the guidance contained in this document, in some cases it may still not be considered acceptable based on site circumstances. Likewise, certain developments may not comply with all guidance but could still be considered acceptable, particularly in the Principal Town, and Small Towns/Large Suburban Settlements, and other locations where high-density development is considered appropriate , and a relaxation of standards may be justified to enable efficient and effective use of land. All applications will be assessed and determined on their own merits. The following criteria provide more detailed guidance for all new residential development including new dwellings, replacement dwellings, and extensions or alterations to existing dwellings. For the purpose of these guidelines, the Town and Country Planning Act defines the term ‘habitable rooms’ as rooms used or intended for the use of sleeping or living which are not solely used for cooking purposes. This would exclude bath or toilet facilities, service rooms, corridors, laundry rooms, hallways or utility rooms. Habitable rooms are considered to be living rooms, dining rooms, shared kitchen-living spaces, studies and bedrooms. Non-residential space is not given the same degree of protection as residential properties. However, proposals should still ensure that development provides for suitable standards of amenity for existing and proposed non -residential space to maintain these as attractive spaces contributing to the economy of the district, and that commercial development including new buildings, replacement buildings and extensions or alterations to existing buildings do not adversely affect the character or amenities of the district. Privacy All developments are expected to maintain acceptable standards of privacy for both new and existing residential buildings. The degree of overlooking and privacy inherent in a development will depend on density, layout, distances and angles between building s, internal layout, positioning of windows, relative levels and, to some extent, the presence of trees, hedges or other landscape features. In the interests of privacy and to prevent unacceptable levels of overlooking: a) Distances between buildings must be sufficient so as to prevent unacceptable levels of overlooking, particularly from upper floors. Areas of particular sensitivity are habitable rooms, the first 3m of private space behind a rear elevation and balconies or terraces which are the sole source of private outside space for a home. As an indicativ e figure, 22m is considered a reasonable separation distance to ensure privacy levels are protected. Distances should be at least 24m between buildings if they include external balconies or are in exce ss of three storeys (especially dwellings/flats) with elevations which directly face one another or in situations where there are site level differences involved. However, the characteristics of the site may allow some degree of variation, for example where there is a difference in ground level between buildings, where buildings face each other at an angle and where impact on privacy levels can be satisfactorily mitigated, including sites within an urban environment. Mitigating circumstances such as careful layout and orientation, screening and window positions may allow a reduction of distances between elevations. b) A proportion of each garden should be a private zone abutting or close to the dwelling that is not visible from the gardens or ground floor habitable rooms of adjoining properties. This should be of a minimum distance of 3 metres from a wall of the dwelling and be permanently screened by walls or fences. c) Development must not incorporate balconies, raised platforms and patios or first floor conservatories which unacceptably overlook neighbouring properties and will only be acceptable where there is no perceived or direct overlooking. Raised platforms and patios that requir e privacy screens which visually impact neighbours will not be supported. d) Trees and hedges (either existing or planted as part of the development) are crucial in planning as they can provide an effective screen and additional privacy, and they should be safeguarded throughout construction and lifetime of the development. To ensu re privacy, trees and hedges should not be solely relied upon due to the potential loss of leaves in winter or the possibility of storm damage and disease etc. Where trees are relied on in any development, a tree management plan is required to ensure their future protection. e) Windows of habitable rooms at first floor level must not be located in flank elevations where they will result in unacceptable levels of overlooking or result in an un -neighbourly relationship. Flank windows of other rooms should be non - opening, below 1.7m (from internal floor level) and fitted with purpose made obscure glazing. High level windows with a sill height of 1.7 metres or more may be acceptable where a secondary light source is necessary. f) Ground floor windows should be located away from flank boundaries. Where flank windows to ground floor habitable rooms have to be incorporated, the boundary must be satisfactorily screened by a fence, wall or evergreen hedge. g) Reliance should not be placed on high screening fences or walls (2 metres and above) where these would form a dominant and oppressive feature. Prospect Developments which rely on outlook over garage courts, extensive parking areas, railway lines etc. will be discouraged where this can be avoided. All residential units where possible should have an outlook over a public or private highway, garden or other open space. Where the rear of a building looks onto the side of another (for instance at a corner in a housing layout), the distance between them must be sufficient to avoid the flank wall having an overbearing effect. Daylight, Sunlight and Outlook Development should ensure a good level of daylight, sunlight and outlook, throughout the day and the year and minimise impact on surrounding properties and spaces. The design of all development is required to maximise natural light into the room (subject to passive heating and cooling considerations). All dwellings should provide for direct sunlight to enter the main habitable rooms for a reasonable period of the day. Living rooms, dining rooms and open living or dining kitchen spaces should preferably receive direct sunlight. Aspect All new residential units should be dual aspect, unless provision of dual aspect is demonstrated to be impossible or unfavourable. Where such circumstances are demonstrated, all single aspect units must: a) Provide a good level of daylight for each habitable room, and optimise opportunity for direct sunlight; b) Ensure that the aspect is not predominantly north-facing and does not face onto main roads or other significant sources of air pollution and/or noise and vibration, which would preclude opening windows; c) Provide a good level of natural ventilation throughout the dwelling via passive/nonmechanical design measures; and d) Ensure that future occupiers have a good level of privacy and do not experience adverse impacts from overlooking. Flatted Developments Proposals for flatted development or involving the conversion of residential unit(s) into a larger number of units must provide for a good standard of amenity for all occupiers and consider the effect of development on the amenity of adjacent properties, and put in place measures to address any adverse impacts raised. This will include (but is not limited to) the following considerations: a) Internal communal corridors should be a minimum of 1.5m wide and should ideally have windows which open to promote cross ventilation and maximise daylight; b) Common/shared entrances should lead to a hall large enough for people to manoeuvre with shopping and/or baby buggies, and in wheelchairs, with ease; c) Access cores must provide an access control system, with entry phones in all dwellings linked to a main front door with remote electronic lock release; d) Internal layouts, including the relationship of rooms on different floors within the scheme, and the position of entrances, extensions and fire escapes should ensure utility for all occupiers. If internal layouts are unable to maintain room relationships, details of acoustic insulation will be required. Residential Amenity Space This section refers to provision of private and semi-private communal amenity space to serve individual dwellings rather than requirements for public open space. New residential development should provide private outdoor amenity space within the curtilage of the development in accordance with the following indicative minimum levels: a) Houses • 2 bed house – 45sqm; • 3 bed house – 60sqm; • 4 bed house - 75sqm; • Additional bedrooms – 15sqm each b) Flats (space may be allocated specifically to each flat or provided communally) • 1 bed flat - 15sqm; • 2 or more bed flat – 25sqm. • The minimum depth and width of balconies and other private external spaces should be 1.5m. If required, mitigation such as privacy screens should be incorporated to avoid unacceptable levels of overlooking c) Specialist and Supported Housing for older people: • 15sqm per bedspace to be provided communally Developers are encouraged to exceed these standards where applicable. Where developments are not able to meet the standards, such as where existing buildings in town centres are converted to residential use, the council may consider lower levels (of amenity space) being provided if the standard of living for future residents is not compromised. Amenity space provided should be of practical shape and usable, with care taken to ensure the space offers a good standard of amenity. Where privacy is achieved by means such as careful layout, screening, or differing levels, rear gardens may be of varied lengths. However, where rear garden length alone is relied on to provide privacy the minimum length should be 11 metres. Depending on the character of the development, the amenity space provided may be in the form of private gardens or in part, may contribute to formal spaces/settings for groups of buildings or existing mature trees. In the latter case this can help avoid problems which can arise from the proximity of large trees to houses. Communal space for flats should be well screened from highways and casual passers-by but should benefit from good levels of natural surveillance. Amenity space that lacks clear landscape proposals and consists of simple grassed or hard surfaced areas will not be acceptable. Where space in the front of a dwelling is assigned to that particular property, it should be defensible space in the sense of being enclosed as part of the original layout. Purely visual amenity space plays a different role; it should be prominent and may well include mature trees and key areas of planting and serve as a visual asset to the development without necessarily being heavily used by the occupants. Built Form All proposals should be in keeping with the prevailing landscape and streetscape, reflecting the variety of local building types by using complementary building materials and designs, and should not result in overdevelopment or unacceptable intensification by reason of scale, form, bulk, height, spacing, density and design. New development, including extensions to existing properties should take into consideration impacts on neighbouring properties, both within and surrounding the development, and visual impacts generally. Oversized, unattractive and poorly sited development can result in loss of light and outlook for neighbours and detract from the character and appearance of the street scene, or original property in the case of extensions. Few properties are designed to incorporate future extensions, therefore any additions built need to take into consideration their effect on neighbouring properties and their visual impact generally. Where planning permission is required, planning applications will be assessed on their individual merits. New development and extensions or alterations to existing properties must: a) Not be excessively prominent in relation to adjacent properties or to the general street scene; b) Have the appropriate number of car parking spaces and/or garages in accordance with the council's Parking Standards; c) Respect the character of the property/street scene particularly with regard to the spacing of properties, roof form, positioning and style of windows and doors, and materials; d) Not result in significant loss of light to the windows of neighbouring properties nor allow unacceptable levels of overlooking Single Storey Extensions Side extensions: proximity to the flank boundary will be individually assessed. Rear extensions: generally, the maximum depth should be 3.6m, or 4m in the case of detached dwellings. This distance may be reduced if the extension would adversely affect the amenities of occupants of adjoining properties or be unduly prominent. Front extensions: applications will be assessed on their individual merits but must not result in significant loss of light to windows of a neighbouring property nor be excessively prominent in the street scene. Two Storey Extensions Side extensions: in order to prevent a terracing effect and maintain an appropriate spacing between properties in character with the locality: • First floor extensions (i.e. over a garage or previous ground floor extension) shall be a minimum of 1.2m from the flank boundary • Two storey extensions may be positioned on the flank boundary provided that the first floor element is set in by a minimum of 1.2m. This distance must be increased in low density areas or where the extension would have an adverse effect on an adjoining property. In high density areas an absolute minimum of 1m will be considered See Figure A.1 for illustrative examples. Rear extensions: in terms of design, mass and volume, each application will be assessed on its individual merits according to the characteristics of the particular property. Front extensions: applications will be assessed on their individual merits but should not result in loss of light to windows of a neighbouring property nor be excessively prominent in the street scene. Two storey development should not intrude into a 45 degree splay line drawn across the rear garden from a point on the joint boundary, level with the rear wall of the adjacent property. This principle is dependent on the spacing and relative positions of the dwellings and consideration will also be given to the juxtaposition of properties, land levels and the position of windows and extensions on neighbouring properties. Figure A.2 provides illustrative examples. Figure A.1 Single and Two Storey Side Extensions and New Development – Flank to Boundary Distances The first floor element of two storey development must be set in from the boundary. The ground floor element may be built up to the boundary Figure A.2 Two Storey Rear Extensions and New Development – Examples of the 45 degree rule Rear extensions should not intrude into a 45 degree splay line drawn across the rear garden from a point on the joint boundary, level with the rear wall of the adjacent property. Staggered layouts: Greater depth may be possible but indefinite ‘leapfrogging’ by successive extensions will not be permitted If the neighbour’s extension is deeper than policy compliant guidance (i.e either 3.6m or 4m depending on dwelling type), then the 45 degree splay line is taken from the policy compliant depth from a point on the joint boundary New Development Development at first floor level and above should be set in from flank boundaries by a minimum of 1.2m. This distance may be increased in low density areas or where development would have an adverse effect on an adjoining property. In high density areas, an absolute minimum of 1m will be considered. See Figure A.2 for illustrative examples. Dormer Windows Dormer windows should always be subordinate to the main roof. They should be set below the existing ridge level, set in from either end of the roof and set back from the plane of the front or rear wall. The roof form should respect the character of the house if possible. Front dormers may not always be appropriate in the street scene. Multiple dormers should be proportionate in scale and number to the host roof. The fenestration of any dormer window should respect the fenestration of the floors below. Roof Structures Crown roofs as the main roof structure can exacerbate the depth of properties and often result in an inappropriate bulk and massing. As such, they are generally discouraged and more traditional pitched roofs are generally favoured. Increases to ridge height will be assessed on their own merits at the time of a planning application, and a street scene plan will be required as part of any application. Where roof forms are of a uniform style/height and appearance, it is unlikely that an increase in ridge height will be supported by the council. Hip to Gable and Dutch Gable roof structures are discouraged in the case of semi - detached houses where they would unbalance the pair and result in a loss of symmetry. In some cases, roof forms in a street may be uniform and therefore this type of alteration may erode the group value of the street and will not be supported by the council. Servicing and Ancillary Facilities Careful consideration should be given to services for dwellings, bin and bike storage, access to meter boxes, space for clothes drying, places for deliveries and EV charging points where relevant. These should be designed to ensure that they are discreet and can easily be used in a safe way and should be designed as part of the building envelope wherever possible. In all cases facilities should be designed to minimise visual impact on the street scene and ensure the amenities of neighbouring occupiers. Provision of sufficient and accessible external storage space for the accommodation of containers for refuse and recycling is particularly important and must be carefully designed and located to be accessible to the occupiers of developments and waste operatives and to minimise impacts on the character and amenities of an area. The layout and location of parking areas are key features affecting the overall quality of residential and commercial schemes. There are many different approaches that can support successful outcomes, such as on-street parking, in-curtilage parking and basement parking. The provision, location and type of car parking and service areas will be considered in context to ensure