PLANNING PERMISSION A GUIDE FOR EXTENDING A DETACHED OR SEMI-DETACHED Foreword by Councilor Dave Smith - Chair of the Planning & Highways Committee. Planning Permissions B Introduction

Owners of semi-detached & detached often find it difficult to know how best to extend their homes to provide much needed space for growing and extending families.

This visual guide is intended to show how a semi-detached/detached property can be extended to add habitable space whilst maintaining the right to light and privacy of adjoining neighbours. The guide firstly explains that there are a number of ways to extend a semi-detached/detached property without the need for planning permission, and the Council would encourage homeowners to do this. Where an owner wants to extend beyond the limits of their Permitted Development Rights then planning permission will be required. The guide goes on to provide some ideas and options on

extensions to show what would, and what would not, be appropriate.

Councillor Dave Smith

Councillor Jim Smith

1.

PLANNING PERMISSION IS NOT USUALLY REQUIRED FOR THE FOLLOWING:

Rear Dormer

• Maximum additional volume of 50 cubic metres • Positioned below the ridge • Set back at least 20cm from the eaves • Materials must match the existing , e.g. the dormer must be clad with tiles or slates • No verandas, or raised platforms 20cm

Side Dormer

The same requirements as the Rear Dormer apply, plus:

Windows must be non-opening unless the opening is at least 1.7 metres above the fl of the

Roof

The insertion of a roof generally does not require planning permission if it does not project more than 15cm beyond the roof slope, or higher than the ridge. However, if additional volume is created it may be treated as 15cm an extension and seperate rules will apply.

Always Check! Always check with the Council because there may be a restriction on the property.

2.

PLANNING PERMISSION IS NOT USUALLY REQUIRED FOR THE FOLLOWING:

Single Storey Rear Extensions Planning Permissions BwD

• Projects no more than 4 metres beyond the rear of the original house, • Materials should be of similar appearance to the existing dwelling • Must not exceed 50% of the total garden area (including the front garden if there is one) • Must not include a veranda, or raised platform • Maximum height 4 metres • Must not exceed the height of the existing dwelling • Maximum eaves height 3 metres if within 2 metres of the boundary. • The eaves height must not exceed the existing eaves height

Always Check! Always check with the Council because there may be a restriction on the Eaves - property. If this is the case the point where Planning Permission will be the wall meets required. the roof

3.

PLANNING PERMISSION IS NOT USUALLY REQUIRED FOR THE FOLLOWING:

Single Storey Side Extensions Planning Permissions BwD

• Must not extend beyond a wall which fronts a highway • Must not wrap around the rear of the original house

• Must not exceed 50% of the original garden area • Maximum eaves height 3 metres if within 2 metres of the boundary • Must not exceed the height of the existing dwelling • Maximum height 4 metres

• The eaves must not exceed the existing eaves height • Must not have a width greater than half the width of the original house

• Must not include a veranda, balcony or raised platform • Materials should be of similar appearance to the existing dwelling

Always Check! Always check with the Council because there may be a restriction on the property. If this is the case Planning Permission will be required. For example, if the property is in a Conservation Area planning permission will be required for a side extension.

4. PLANNING PERMISSION IS NOT USUALLY REQUIRED FOR THE FOLLOWING:

Two Storey Rear Extensions Planning Permissions BwD

• Must not exceed 50% of the original garden area, including any • Must not project beyond the side of the original house previous extensions • Must not be within 2 metres of any boundary • Must not exceed the height of the existing dwelling • Must not include a veranda, balcony or raised platform • The eaves height must not exceed the existing eaves height • Materials should be of similar appearance to the existing dwelling • Projects no more than 3 metres beyond the rear wall of the original house, and must not be within 7 metres of the rear garden boundary

Always Check! Always check with the Council because there maybe a restriction on the property. If this is the case Planning Permission will be required.

5. PLANNING PERMISSION IS NOT USUALLY REQUIRED FOR THE FOLLOWING:

Porch (outside any external of a house Planning Permissions BwD

• The ground area (measured externally) of the structure must not exceed 3 square metres

• Must not exceed 3 metres height • Must not be within 2 metres of any boundary with the highway or pavement

New or Replacement Front Driveway (over 5 square metres) • Must be made of porous materials which allows rainwater to soak through, or rainwater run-off must be directed to a porous area within the site and not onto the road

Single Storey outbuilding

• The total ground area covered by must not exceed 50% of the total area, excluding the original house • No part of the must be situated on land which is forward of the Always Check! front wall of the house Always check with the Council because there • Must not exceed 4 metres height (dual-pitched roof), 2.5 metres height if it may be a restriction on the is within2 metres of the boundary, or 3 metres height in any other case property. If this is the case • Eaves height must not exceed 2.5 metres Planning Permission will be required. • Must not include a veranda, balcony or raised platform 6.

PLANNING PERMISSION IS NOT USUALLY REQUIRED FOR THE FOLLOWING:

Renewable energy Planning Permissions BwD

The planning system allows for certain types of renewable energy developments on to proceed without needing to apply for planning permission as long as certain conditions are met. These include:

• panels • ground source heat pump • water source heat pump • flue for a biomass heating system or a combined heat and power system • air source heat pump • wind turbine not to exceed 15m in height(detached houses only)

Always Check! Please see the individual technology fact sheets for further information via the Council website. Please note: if the building is listed or within a conservation area additional restrictions will apply. To avoid confusion, it is always recommended that you contact the council’s Planning Department before installing any renewable energy technology to confirm whether or not planning permission is required. 7.

WHEN PLANNING PERMISSION IS NEEDED

All extensions Planning Permissions BwD

The 45 Degree Rule ELEVATION VIEW

The council applies the 45 degree rule as an indicator when assessing proposed extensions, to ensure that a satisfactory relationship is maintained between existing buildings and proposed extensions.

Extensions are measured at an angle of 45 degrees from the midpoint of the closest window in a habitable room of a neighbouring property. If the extension lies within the 45 degree angle when measured horizontally or vertically, an unacceptable loss of daylight and dominance may be caused and planning permission may be refused. 

In the case where the neighbouring window is a door, the 45 degree angle is measured from 1.6 metres above the ground on the centre line of the window. o 45

 PLAN VIEW

4

5

o 450

) Habitable : living rooms,  450 dining rooms, 8. /diner and

Bathroom (non-habitable

WHEN PLANNING PERMISSION IS NEEDED

All extensions Planning Permissions BwD

Parking Requirements Overdevelopment Adequate parking space must be retained within the site in Extensions should ensure that adequate garden space is left open for the accordance with the Council’s adopted Parking Standards. If new storage of bins, maintenance, clothes drying and to safeguard the health of parking spaces are to be created in the front garden area, at least one residents in respect of light and air. third of the garden should be kept as a planted garden rather than hard surfacing. For example 2-3no. bedrooms will require 2 spaces, Seperation Distances and 4no. bedrooms will require 3 spaces. The car parking standards A distance of no less than 21 metres must be maintained between facing are available on the Council’s planning website. windows of habitable rooms, and a distance of no less than 13.5 metres must be maintained between a habitable room window and a blank gable or wall with only windows to non-habitable rooms.

9. WHEN PLANNING PERMISSION IS NEEDED

Front Dormer Planning Permissions BwD Do  Do not  the following pages aim to show examples of alterations which require planning permission and how best to achieve a planning approval.

 • At least two thirds of the original roof  plane is retained  • Matching Materials • No larger than existing windows • Pitched roof rather than flat roof • Leave 1 metre distance to the party • Do not exceed the ridge height of the original roof

• Too big • Materials don’t match • Flat roof is a poor design • Windows too big  • Box-shaped and too bulky

Always Check! If the property is within a Conservation Area, or there are no other front dormers on the street, it is unlikely that planning permission would be granted.

WHEN PLANNING PERMISSION IS NEEDED

Rear Dormer Planning Permissions BwD

• Dormer covering all of the roof area and above the ridge. • Materials not matching the original roof

• Dormer roof set lower than the original ridge height. • Set in from both side boundaries. • Clad in materials to match the original roof.

If the property is in a Conservation Area, dormer extensions are unlikely to receive planning permission due to their impact on the character of the historic area. 11.

WHEN PLANNING PERMISSION IS NEEDED

ground Rear extensions Planning Permissions BwD Do  • Include a sloping roof • Prevent loss of daylight or overshadowing of neighbouring houses • Retain some rear garden / yard space for bins, maintenance and clothes drying.

• Consider 45 o rule (see Page 8)

 

Do not • Flat Roof  • Site where adjacent properties have no extensions

• Project extension full length NOT ALL DEVELOPMENTS ARE THE SAME of the garden The following will have a bearing on whether extensions will be allowed. • Number, location and size of extensions at adjoining properties. • Overshadow the next door • Position of the property in relation to the sun.

rear window • Different ground level e.g Sloping site.

• Location of and windows in the next door property. • Design of the extension and harmony with the original house 12.

WHEN PLANNING PERMISSION IS NEEDED

Two Storey Rear Extensions Planning Permissions BwD

Two storey rear extensions usually require planning permission. In many cases, planning applications are rejected because a two storey extension close to neighbouring houses can significantly harm the living conditions of neighbours through overshadowing, loss of privacy, or dominance.

The following pages show five situations where two storey rear extensions may be acceptable, on semi-detached houses.

1. Sloping Site Overshadowing and dominance can be minimised if the site of the extension is lower than the immediate neighbour.

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WHEN PLANNING PERMISSION IS NEEDED

Two Storey Rear Extensions Planning Permissions BwD

2. Joint extension across two houses Overshadowing and dominance can be avoided if two houses build a joint extension at the same time.

14. WHEN PLANNING PERMISSION IS NEEDED

Two Storey Rear Extensions Planning Permissions BwD

Bathroom

extension

3. Nearest neighbouring windows are for non-habitable rooms Overshadowing or dominance of a non-habitable room (such as bathroom or hallway) in some cases does not cause significant harm to the living conditions of neighbours and may be acceptable. Please refer to the 45 degree rule which is explained on Page 8. 15. WHEN PLANNING PERMISSI0N IS NEEDED

Two Storey Rear Extensions Planning Permissions BwD

4. Built next to an existing extension at an adjoining house Overshadowing and dominance can be minimised if the extension is built next to an existing extension at a neighbour’s house. (Subject to the adjacent window serving a non-habitable room) Please refer to the 45 degree rule which is explained on Page 8.

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WHEN PLANNING PERMISSION IS NEEDED

Two Storey Rear Extensions Planning Permissions BwD

5. Outer Edge of Building Overshadowing and dominance can be minimised if the extension is built at the outer edge of the building, away from the nearest neighbour.

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WHEN PLANNING PERMISSION IS NEEDED

Side extensions Planning Permissions BwD Do  Do not  • Match the roof shape of the original house • Flat Roof  Flat Roof

• Refer to the 45 degree rule (see page 8) • CreateCreate a terracingterracing effect effect  Project beyond the front build line • Do not project beyond the original front of the house • PrOnoject corner beyond plots, dothe not front project build beyond line the side build line • Have a lower ridge than original roof • Keep a gap of at least 1 metre between properties • On corner plots, do not project beyond the side build line

• Match materials, window styles and positions • For two-storey side extensions, the first floor should set be back from the front of the house by at least 1.5 m and etres the eaves level should match the existing eaves level

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 Two storey extensions up to the side boundary and flush with the original front wall remove the visual separation between the buildings and create the impression of a continuous

The preferred approach is to maintain a gap between properties: this is the best way to prevent a terracing effect. other options may also be available for extending or gaining extra living space.

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WHEN PLANNING PERMISSION IS NEEDED:

Porches Planning Permissions BwD

Conservatories • Match the roof shape of the original house • Match the style and the materials of the house • Dwarf walls should be included with materials to • In keeping with the appearance of the street and match the house does not detract from the character of the street • Refer to the 45 degree rule and separation distances described on page 8. • Where a conservatory is adjacent to a boundary with a neighbour, an acceptable degree of privacy should be maintained by means of a solid side, obscure glazing or screening by a fence or wall on the side facing the neighbour.

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GREATER FLEXIBILITY RELATING TO EXTENSIONS AND THE PRIOR APPROVAL PROCESS

Class A

Single Storey rear extensions:

You may extend beyond the rear wall of the original dwellinghouse up to 8 metres (detached dwellinghouse), or 6 metres (semi- detached dwellinghouse) subject to the following:

It must not exceed 4 metres in height The enlarged part of the dwellinghouse would be within 2 metres of the boundary of the curtilage of the dwellinghouse, and the height of the eaves of the enlarged part would not exceed 3 metres.

Materials must match the existing dwellinghouse

You must submit your notification to the local planning authority and include further information regarding the proposed extension to enable the authority to determine the application. The authority has 42 days from receipt to notify you whether the proposed development would be permitted development.

Further guidance is available on the Council’s planning web page.

WHAT TO DO NEXT… Planning Permissions BwD

Before starting any work you are advised to check to see if planning permission is required.

When a planning application is submitted: If your application is refused, a revised application of If planning permission is required, we can • We will write to your immediate neighbours the same character and description can usually be offer you professional advice before you explaining your proposal to ask for their comments submitted within 12 months of the refusal date without formally submit a planning application. This • In some cases we may put up a site notice or requiring a further planning fee. is a discretionary and chargeable service advertise the application in the press. e.g. in offered by the Council. Having early Conservation Areas and/or Listed Buildings Alternatively, you may wish to appeal to the Planning constructive discussions will help you save • We will not make a decision until we have allowed at Inspectorate against the Councils Refusal. time, avoid wasted expense and frustration over any delays in the processing of your least 21 days for comments to planning application. Pre-application enquiry be made. We will take account of all comments Please note: forms and scale of fees can be downloaded received prior to a decision being made. You are advised to contact Building Control – their from the planning pages of the council’s • The planning case officer will assess the application separate permissions may be required for certain against the relevant legislation and policies, internal and external alterations. Contact (01254) website www.blackburn.gov.uk/planning. taking into account any comments received from 505022 or email: [email protected] APPLY interested parties. The case officer will then make If planning permission is required, you can complete and a recommendation as to whether it should be submit your application yourself or you can employ an approved or refused. agent to draw your plans and act as your representative • The final decision will be made by either the Director of Regeneration or the Planning & Highways when dealing with the planning department. The Council Committee within a target timescale of 8 weeks. does not recommend particular agents however a list of planning agents can be found on the Royal Town • The decision notice will be posted to you (and your Planning Institute’s website: www.rtpi.org.uk; and a agent if you have appointed one). list of architects can be found on the Royal Institute of Blackburn with Darwen Borough Council

British website: www.architecture.com. Development Management Team

Lower Ground Floor Planning application forms and guidance notes can DECISION Old Town be downloaded from the planning section of the There are two types of decision that can be made: King William Street council’s website www.blackburn.gov.uk/planning, Permits or Refuses. Blackburn BB1 7DY which provides detailed guidance on the supporting www.blackburn.gov.uk information and scale of fees. It is important to provide In most cases, planning permissions are subject to as much relevant information as you can to avoid any conditions that are listed on the decision notice. For unnecessary delay in the progress of your application. example, you must commence work within 3 years of If in doubt please contact us. the date of the permission.

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