Residential Design Guide

Ended on the 7 May 2018

(2) SECTION 8

Detailed design

A series of guidance sheets covering detailed design situations has been published by the Council. These are reproduced in the appendices to this document and are also issued as stand- alone guidance sheets with their accompanying notes. They cover the following issues:

Side extensions on detached dwellings
Side extensions on semi-detached dwellings
Overlooking
Corner properties
Distance separation and open spaces
Rear extensions and the 45˚ rule
Roof dormers
Extensions to terraced houses in conservation areas

Side extensions should be no more than 2/3 of the width of the original property
There should be a set back of 450mm
There should be a set down of 225mm

See appendix 3 for details

Side extensions for detached dwellings

Fig 1 Traditional pitched roof detached dwelling with totally inappropriate flat roofed extension

It is important that side extensions should relate to the design of the original building with matching roof shape and pitch. (Hipped or Gabled).
Extensions to detached dwellings should always seek to enhance the overall design unity.
Set backs to ridge levels and facade junctions helps to ensure that new extensions remain subordinate to the existing dwelling. For a facade this also helps to overcome visual problems associated with slight variations between existing brickwork dimensions and the new work.
There may be scope in some instances to have a contemporary architect designed 'modern' extension. Quality of design, detailing and materials will be significant considerations. Each case will be viewed on its own merit.

Hipped Roofs

Fig 2 DON’T add a two or more storey flat roofed side extension to a traditional hipped roof dwelling

Fig 2 DON’T introduce single storey flat roofed extensions to the side of traditional hipped roofed detached dwellings

Gabled Roofs

Fig 2 DON’T add a two or more storey flat roofed side extension to a traditional gabled roof dwelling

Fig 2 DON’T introduce single storey flat roofed extensions to the side of traditional gabled roofed detached dwellings

Fig 2 DO ensure that any new extension is generally subservient to the existing dwelling

Fig 2 The overall size and scale will vary according to site conditions, constraints and circumstances

Fig 3 Windows to new extensions should match and line through with the existing. A small set back helps visually delineate new and existing

Fig 4 DON’T under general circumstances introduce a gabled extension at right angles to an existing hipped roof

Fig 4 DON’T let any new extension dominate the existing dwelling by reason of its height, width, length or general massing. circumstances

Side extensions for semi-detached dwellings

Fig 5 Semi detached dwellings are normally Fig-6 designed as a matching pair. It is important that this character is respected and not compromised by any new extension.

Fig 5 DO relate the design of any new extension to the form and character of the existing dwelling with a 450mm min set back between existing building and new extension

Fig 6 DON’T let any new extension dominate the existing, by reason of massing material or height.

Fig 6 DON’T introduce a gabled roof extension to an existing semi detached hipped roof dwelling.

Flat Roofed Extensions

Fig 6 DON’T introduce two storey flat roofed extensions. They are not considered appropriate or acceptable.

Fig 6 DON’T introduce single storey flat roofed extensions to the side of semi detached dwellings.

Fig 7 DO ensure that any extension is subservient to the existing dwelling.

Fig 7 DON’T change the traditional compositional balance of the semi detached dwelling by introducing a new extension that runs continuously from the existing roof or wall line.

Corner plots

Corner plots are often larger than those of neighbouring dwellings; They can provide welcome open space in the streetscape-often enhanced by landscape planting.

Fig 8 DO respect the existing character of the streetscape.

Fig 8 DON’T design any extension that substantially reduces the openness of the traditional corner plot.

Side Extensions & Semi Detached Dwellings

The design and form of any extension to a semi detached dwelling should be compatible and generally subservient to the existing property. Windows, doors and other features should line through.

Flat roofed extensions

In certain discrete locations contemporary extensions to traditional buildings may be acceptable.

Overlooking

Fig 9

Two Storey Side Extension with balcony

Single Storey Side Extension with balcony

Site boundary

Side facing windows in extensions of two or more storeys, where they overlook private gardens will not normally be permitted if they add significantly to existing levels of overlooking.
For habitable rooms windows overlooking adjacent properties are not acceptable.
In certain instances small non opening windows with obscure glazing may be acceptable for non habitable rooms.
Flat roofed extensions to the side of an existing dwelling with balconies and/or roof gardens are not acceptable where there is a potential for overlooking.

Two Storey Side Extension

Generally, new overlooking windows will not be permitted DON’T have windows at high level overlooking adjacent property

Fig 10 There may be problems with side windows on single storey side extensions

Distance Separation - Side Extensions

Fig 11 Typical street scape elevation, having a building rhythm

Distance Separation - To Avoid Terracing Effect

Fig 12 DON’T build any new two storey side extension on the existing boundary. Two storey side extensions built up to a common boundary would adversely effect the character of the area; and will normally not be permitted.

Fig 12 DO have a minimum distance separation between a common boundary and any new extension. A minimum 1m distance from the common boundary and the first floor gable wall of a new two storey extension should be provided. Single storey extensions on the ground floor part of a two (or more) storey extension may be built up to the boundary.

Distance Separation Between Fronts & Backs

Fig 13 In addition to distance separation the provision of adequate garden/ amenity spaces will be a material consideration in any proposal.

Fig 14

Fig 15 The impact of a garden structure / garage on a neighbours property may be a material consideration.

Overlooking : Patios and Balconies

Fig 16 In addition to distance separation the provision of adequate garden/ amenity spaces will be a material consideration in any proposal.

Fig 17 Generally patio/ balcony infilling at roof level is not considered appropriate. Such elements can be both extremely visually intrusive and can result in considerable and inappropriate overlooking problems.

Single Storey Extensions – 45 Degree Rule

Fig 18 Ground floor plans

Fig 19 Diagrammatic View

Two Storey Extensions – 45 Degree Rule

Fig 20

45 degree taken from the centre point of the nearest window or windows of a habitable room. The line is taken from the original face of the adjoining property.
For two storey extensions, the 45 degree line at ground level is taken from the nearest ground floor 1/4 point of habitable room window.
For two storey extensions, the 45 degree line at first floor level is taken from the nearest 1/2 (centre) point of a habitable room. (see appendices for supplementary planning guidance)

Roof Dormers

Fig 21 DON’T introduce long horizontal box dormers.These are not traditional elements of the districts towns, and will not be permitted, particularly in Conservation Areas.

Fig 21 DON’T locate a new dormer on the boundary edge of the roof or on the eaves line.

Fig 21 DON’T locate dormers at ridge hight level or on the edge of dwellings roof.

Fig 21 DO maintain a gap of at least 1m between any new dormers and eaves line and/or edge of roof dwelling.

Fig 22 DO consider a modest dormer window; appropriately and sensitively located on the roof slope.

Fig 22 DO generally consider locating any new dormer within the lower 2/3rds of the roof slope.

Details - Rooflights Good Practice in Listed Buildings

Fig 23 Projecting rooflights on pitched roofs can be a considerable source of visual intrusion on a traditional roofscape. For listed buildings and those in Conservation Areas, consideration should be given to siting any new rooflights flush with the roof slope; This produces a far more acceptable, less visually intrusive detail. DON’T locate large projecting rooflights on prominent elevations.

Fig 24 DON’T locate large projecting rooflights on prominent elevations.

Balcony and Railings

Fig 25 DO ensure that repair/reinstatement work is undertaken using appropriate and correct materials, detailing and workmanship DO ensure that all the necessary formal approvals have been obtained prior to any work being undertaken.

Fig 25 Balconies and railings are a typical feature of Recency townscape. Where they are missing or defective DO give consideration to reinstatement and/ or repair as necessary.

Details - Windows

Fig 26 Traditional timber windows would invariably be set well back into the window reveals. This helps to produce shadow and modelling to a building fenestration. DO consider the location of the window frame carefully.

Fig 27 DON’T install new windows flush with the surrounding brickwork face.

Roof dormers

Dormer windows will only be permitted where they can be inserted without damaging the character and appearance of the building and the general area and without unreasonably affecting the amenity of the neighbours.

Dormer windows should be avoided on prominent elevations that can be clearly viewed from the street; kept well below the ridge line and away from the edge of roofs.

No dormer should be erected within 1m of the eaves line of the house; there should be a minimum distance of 1m between a dormer window and each side boundary of the property.
Do use traditional modest pitched roof or lead roof dormers.
Do not introduce felted flat roofed dormers of modern style unless on an appropriate modern house

There is a series of guidance and permitted development self assessment forms to help you determine whether or not you need planning permission for your proposals, available on our website

Extensions to terraced houses in Conservation Areas

Much of the District's urban Conservation Areas, particularly in Royal Leamington Spa, are comprised of rows of 19th Century terraces, which are characterised by rear wings and side courtyards with modest rear gardens.

In order to strike a reasonable balance between allowing some scope to extend these properties and protecting the character and appearance of the Conservation Areas together with the living conditions of the occupiers of neighbouring properties, the District Council suggest a side courtyard extension which adheres to the following design principles:

Include a set back and have a glazed roof with a largely glazed end wall to reflect the open side courtyard feature which formed part of the original layout.
Set the eaves height at no more than 2 metres, which is the equivalent of the height of the boundary wall which can be built without permission under the Government's impact based permitted development rights together with a glazed roof in order to mitigate the impact on loss of light and outlook from the neighbouring properties.

For instructions on how to use the system and make comments, please see our help guide.