Brief Guide to Home Extensions and Alterations

8/12/2019 Brief Guide to Home Extensions and Alterations

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A brief guide tohome extensions

and alterations

Extract from Residential Extensions

and Alterations SPD

Adopted February 2010


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INTERPRETING AND TRANSLATION ASSISTANCE

This guidance can be made available in other languages, large print, Braille,audio- tape format or a translation service provided on request. Should yourequire access to these services please contact us at the address stated below.

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URDU

Urban Design team, Environment & RegenerationLondon Borough of Waltham ForestRoom G08, Sycamore House,Forest RoadWalthamstow E17 4JF

Tel: 020 8496 3000E-mail: [email protected]

Web site: www.walthamforest.gov.uk


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A Guide to home extensions and alterations

February 2010

Urban Design Team, London Borough of Waltham Forest

1

Contents

1.0 Introduction

2.0 General design principles

2.1 High quality design

2.2 Maintain harmony with the original building

2.3 Respect the street scene and local character

2.4 Neighbourliness

2.5 Garden size

2.6 Consider climate change

2.7 Other issues to consider

3.0 Rear extensions3.1 Existing layout

3.2 Single storey rear extensions

3.3 Two storey rear extensions

3.4 The 45 degree rule

4.0 Side extensions

4.1 Effect on the street scene

4.2 Proposed drainage

5.0 Front extensions5.1 Effect on the street scene

5.2 Porches

6.0 Loft conversions and roof extensions

6.1 Roof light conversions

6.2 Dormers

6.3 Hip to Gable

6.4 Mansard

6.5 Buttery or London

7.0 Alterations for dependent relatives or for those with disabilities

8.0 Detached outbuildings

9.0 Best practice guidance for minor alterations

9.1 Walls, gates, fences and other boundary treatments

9.2 Paving over front gardens

9.3 Cladding or rendering

9.4 Satellite dishes

9.5 Replacement windows

10.0 List of contacts

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1.0 Introduction

This document is a shortened version of Waltham Forest's ResidentialExtensions and Alterations Supplementary Planning Document

(Adopted February 2010). It is intended to give residents a brief

guide to the design requirements for extensions and alterations,

however it is recommended that applicants read the full document

before submitting an application as Council ofcers will use the main

document when making a decision on a planning application.

In assessing planning applications for residential extensions or alterations the Council will

consider the impact of the proposal on:

The appearance or character of the existing house

The appearance or character of neighbouring properties and

the street as a whole

The amenity of neighbouring residents.

It is important to note that not all houses can accommodate an extension. In some

instances there may simply be inadequate space. Also development, however small,

may result in harm to the appearance of the street

or to the amenity of neighbours. Where houses

have already been extended, the cumulative effect

of additions will be taken into account.

The following sections set out the key design

principles that apply to extensions generally and

provide further detail on the different forms of

extension, such as rear extensions, side extensions,

or loft extensions.

The full Residential Extensions and Alterations

document can be found on the Council's website

at www.walthamforest.gov.uk/residential-

extensionsfeb10.pdf. Alternatively the Duty

Planning Ofcer can give advice - Tel: (020) 8496

3000, Email: [email protected] February 2010

Residential Extensions and Alterations

Supplementary Planning Document


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February 2010


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2.0 General Design Principles

2.1 High quality designExtensions or alterations should improve or at least

maintain the character of the house and the street

in which they are situated.

Good design can:

Add value to a property,

Avoid adverse impacts on neighbouring

residents, Require less long-term maintenance.

2.2 Maintain harmony with the original

building

The Council is predominantly interested in the

external appearance of an extension, both in how

it impacts on the street and how it relates to theoriginal building. Proposals should:

Complement the size, shape and character of

the original house with extensions generally

being subordinate.

Complement the roof line of the original

house retaining features such as parapet

walls and chimneys.

Reect the design, position, proportion and

size of windows and doors of the originalhouse.

Use traditional materials for windows

and doors. In some instances modern

alternatives may be appropriate if they are a

suitable design and good quality.

Replicate existing house details such as

chimneys, tiles or decorative brickwork in an

extension.

Complement or match the materials of the

original house with high quality, natural,

durable products.

A good quality mansard roof extension

The front dormer does not complement the

position, proportion and size of windows of

the original building

The roof of this side extension does not

complement the roof of the original house


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February 2010

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When matching materials it is important they

are as exact as possible.

Local reclamation suppliers can be found

on the internet who could help you ndappropriate materials. Alternatively contact

the Councils Conservation Ofcer for

advice (contact details are at the end of this

document).

2.3 Respect street and local character

An extension should not have a detrimental

effect on the street. In many of Waltham Forest'sresidential streets the character is achieved

through uniformity. Windows, doors, roofs, gaps

between properties and other features often form a

repeating pattern along the street which reinforce

or establish its character.

Proposals should:

Respect the size and shape of adjacent and

nearby buildings.

Complement the roof arrangement of

neighbouring properties if visible from the

road.

Not ll in the gap between properties if they

are a characteristic of the street.

Consider the size and position of existing

windows and doors.

Retain or replace other features such as

boundary walls or fences common to the

street.

Alterations or extensions to buildings in prominent

locations should be to a high standard of design

and construction.

2.4 Neighbourliness

Extensions should not compromise the amenity of

neighbours in terms of:

Gaps between buildings are sometimes

a strong character of a street. In theseinstances large side extensions should

generally be avoided

Front garden walls have a great impact

on the street scene and should wherever

possible be retained

The details of this extension follow those of

the original house


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Loss of privacy. This can often be avoided

by carefully locating or omitting windows to

prevent overlooking

Existing outlook. Developments that areoverbearing to neighbours and limit their

views should be avoided.

Loss of light.

2.5 Garden size

Extending your home may mean reducing your

garden size. The Council see it as important for a

home to provide appropriate garden space, so will

consider the impact of your extension on the size

of the garden.

The Council will generally require 15m of

usable private garden space per habitable

room.

Habitable rooms include all rooms normally

used for living and sleeping as well as

kitchens of 13 m or more in size.

2.6 Consider climate change

Making the whole house energy efcient will:

Save money on bills,

Make the property more attractive to buyers

Increase the ratings on the Energy

Performance Certicate.

Measures could include:

Insulation

Using water efcient appliances and energy

efcient boilers

Incorporating small-scale renewable energy

systems such as solar panels, or small-scale

wind turbines

Installing a green roof to reduce ooding


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Using paving that allows water to soak

through to reduce ooding

Collecting and reusing rain water.

(For further information please see the full

Residential Extensions and Alterations

Supplementary Planning Document on

www.walthamforest.gov.uk/residential-

extensionsfeb10.pdf).

2.7 Other issues to consider

Natural light Will there be enough natural light inside the

house after the extension?

Drainage

Has existing drainage been considered?

A frequent problem faced by homeowners

extending their home is that of existing

drainage. Many properties, particularly those

built around 1920 or 1930, have drainage

pipes that run along the back or side of the

house.

The planning approval process does not

check the feasibility of drainage. You may

therefore be granted planning permission

for an extension, but nd out later that it

cannot be achieved without changes.

If this is the case, it is important you

submit an amended planning application

showing any changes. If changes are made

without permission the Council may require

you to remove the extension (for further

information on enforcement please see the

full Residential Extensions and Alterations

Supplementary Planning Document on

www.walthamforest.gov.uk/residential-

extensionsfeb10.pdf).

The best way to avoid this would be to

contact the Councils Building Control

department (contact details are at the end of

this document) at an early stage to discuss

this and any other potential problems that

you may face.

Drains frequently run along the side or back

of houses which can sometimes affect the

extent of an extension


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3.0 Rear extensions

3.1 Existing layoutThere are generally two arrangements for the

backs of properties (see sketches).

'L-shape- such as the Victorian terraced

houses in Leyton and Leytonstone, and

which are often on narrow plots. It is

generally inappropriate to square the

property off by inlling the L-shape as this

can create a tunnel effect for your neighbour

and therefore be too overbearing.

Square-backed- such as some of the

boroughs Edwardian or interwar houses

in Chingford or Highams Park. Extension

of the square-backed layout is usually less

overbearing for neighbours and therefore

generally acceptable providing detailed

design principles are followed.

3.2 Single storey rear extensions

As a general rule, single storey rear extensions are

more acceptable than higher extensions because

they have less of an impact on neighbours.

Home owners can generally extend the back of the

house by up to 3 metres. Anything over this is

likely to be too overbearing for neighbours in terms

of loss of light, overshadowing and compromising

outlook.

Flat roofs of single storey rear extensions cannot

usually be used as balconiesto the upper levels,

as in most cases would result in direct overlooking

into neighbouring properties.

3.3 Two storey rear extensions

Two-storey extensions are not always appropriate.

An extension of a square rear prolebuilding is usually less overbearing on

neighbours

proposed

extension

original building

It is often inappropriate to inll anL-shaped plot as this can create a tunnel

effect for neighbours

proposed

extension

The 3 metre rule

original property

Proposed

rear

extensionmax 3m

The acceptability of balconies on singlestorey rear extensions will depend on the

impact on overlooking of neighbours


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Side extensions should generally be

subordinate to the original house

This side extension has a detrimental impact

on the street scene. The design of the roof

does not complement the original house

Particular care needs to be taken to ensure they

do not cause an unacceptable loss of daylight or

sunlight to neighbours and are not out of character.

3.4 The 45 degree rule

The Council use the 45 degree rule as a guide

in determining whether an extension has an

acceptable impact on neighbours.

An extension should not exceed a line taken at

45 degrees from the centre of the nearest ground

oor window of a habitable room in an adjoining

property if the proposed extension is single storey.

For extensions greater than one storey, the 45

degree line is taken from the edge of the nearest

window of an adjoining property.

4.0 Side extensions

4.1 Effect on the street

If the gaps between properties are a characteristic

feature of the street a side extension may not be

appropriate (see section 2.3 above).

A side extension should generally be sub-ordinate

to the main part of the house and set back from thebuilding line fronting the street by 1 metre.

The design of the roof, windows and doors

should be in keeping with the original house and

neighbouring properties, and materials should

complement or match those of the original house.

4.2 Proposed drainage

Proposed drainage should be considered early

when planning a side extension. There is often

2storey

exten

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your

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property

neighbours

rear window to

habitable room

proposed

rear

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exten

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a temptation to build right up to the property

boundary and leave insufcient space for gutters.

The Council will require you to deal with the

drainage of your house within the boundary of your

property.

The visual impact of gutters should also be

considered when installing drainage.

5.0 Front extensions

Front extensions generally have a greater impact

on the character of the original house and street,

therefore there are limited circumstances when

they would be considered appropriate.

Front additions would only be considered

acceptable where:

They do not interfere with the established

building patterns and lines of the street

frontages.

They appear as if they are a part of the

original building, incorporating sensitive

design and using materials that match those

of the original house.

5.1 Effect on the street

There may be limited circumstances where a front

extension is appropriate, for example where the

street has an irregular building line or pattern.

In these cases it must be sensitively designed

to the highest quality and the materials should

complement or match those of the original house.

It would need to appear as if it were designed with

the original building and not look out of place in the

street.

Gutters should be located within the

property boundary


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A roof light conversion

A dormer extension

5.2 Porches

The Council will closely scrutinise any applications

for porches to ensure that the proposal does notdetrimentally affect the character of the original

building, and where appropriate, traditionalmaterials should be used. In many cases, for

example with Victorian or Edwardian houses, a

porch may not be appropriate.

6.0 Loft conversions and roofextensions

Bat roosts are sometimes present in lofts or roofs

and if found home owners should contact Natural

England.

It is an offence to damage, destroy or obstruct

access to a bat roost.

6.1 Roof light conversions

The best conversions of this type are those where

the roof lights are of a size and location that relate

to the existing windows of the house, and where

low prole roof lights are used.

6.2 Dormers

Dormers should be located within the prole of the

existing roof and be of an appropriate scale and

bulk to avoid a top heavy appearance.

Dormers should:

Normally be to the rear.

Not have a width exceeding their height. A

width no greater than 1.2m is preferred. Two

smaller dormers with sufcient spacing maybe an acceptable alternative to one large

If not designed well, porches can have a

detrimental impact on the street scene


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dormer.

Not exceed the height of the ridge of the

main roof.

Incorporate size and position of windows,

which relate to windows on the main house.

Where there is an L-shaped footprint to the

building, permission will not normally be granted

for dormer extensions that turn the corner of the

L-shape to create one large extension.

6.3 Hip to Gable

The Council will take into account the impact of the

roof change on the original building and the overall

character of the street. If the extension affects a

building in a prominent location (such as one at the

end of a long view) and if carried out in isolation

would imbalance a pair of houses, the Council may

consider the impact on the street scene to be too

adverse.

All hip to gable extensions must have roof tiles or

slates on the extension that exactly match those ofthe original roof

6.4 Mansard

Mansard roofs are not a typical roof prole in the

borough so it is unlikely that this type of extension

will be appropriate

6.5 Buttery or London

These are present in some of the Victorian terraces

in the south of the Borough.

They usually require a mansard type extension to

achieve the required oor to ceiling heights.

Where they are part of a terrace they will generally

be unacceptable unless carried out in conjunction

with neighbours to achieve a meaningful grouping

of roof alterations.

A large dormer following the l'shaped

footprint

Box type roof extensions often vary in

form and size resulting in an imbalance

with adjoining properties and a detrimental

impact on the street scene

A mansard loft extension

Three home owners have carried out a

successful mansard loft extension together


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7.0 Alterations for dependant

relatives or for those with

disabilities

When adapting a home for a person with a disability

the general and detailed design principles above will

be applied when the application is considered. In

some instances, the Council may require a ramp or

platform lift to be provided at the front of the house

to allow a disabled resident easy access from the

house. This will, however, depend on the needs of

the person being catered for and the existing layout

at the entrance to the house.

For an extension or annexe to be deemed for use

by a dependant relative it is should share the same

entrance, be accessed from the main house, and

be on one level. It should not have its own kitchen

facilities, but share those of the main house.

8.0 Detached outbuildings

Outbuildings are often permitted development

and do not require planning permission, subject to

conditions.

Where planning permission is required the Councilwill consider the size of the proposed outbuilding

compared to the size of the original garden (see

general design principles section above), its design

and its impact on neighbours.


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9.0 Best practice guidance for

minor alterations

9.1 Walls, gates, fences and other

boundaries

If the proposed garden fence gate or wall is no

higher than 1 metre next to a road, or less than 2

metres on any other boundary, you will generally

not require planning permission, unless the house

is in a Conservation Area or is a Listed Building.

Front garden walls have a great impact on thestreet, and should wherever possible be retained

or reinstated.

9.2 Paving over front gardens

Planning permission is now required to lay

traditionally paved driveways at the front of the

house that do not self drain.

For further information please see The Department

for Communities and Local Governments

Guidance on the permeable surfacing of front

gardens which can be obtained at

www.communities.gov.uk/documents/

planningandbuilding/pdf/pavingfrontgardens.pdf.

9.3 Cladding or rendering

Cladding or rendering should be avoided as it often

has a detrimental impact on the uniformity of the

street, particularly if you are adding a nish that is

signicantly different to neighbouring houses.

Clad buildings can be susceptible to damp as the

building can no longer breathe.

9.4 Satellite dishes

In certain circumstances you will need to apply for

Front garden walls generally have a positive

impact on the street scene and should

wherever possible be retained

Cladding can have a detrimental impact on

the street scene and should be avoided
http://www.communities.gov.uk/documents/planningandbuilding/pdf/pavingfrontgardens.pdfhttp://www.communities.gov.uk/documents/planningandbuilding/pdf/pavingfrontgardens.pdfhttp://www.communities.gov.uk/documents/planningandbuilding/pdf/pavingfrontgardens.pdfhttp://www.communities.gov.uk/documents/planningandbuilding/pdf/pavingfrontgardens.pdf


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planning permission to install a satellite dish.

For further detail please contact the planning portal

web site on

www.planningportal.gov.uk/wps/wcm/connect/

Portal2/portal2Site/permission/commonprojects/

antenna/guidance#GoodpracticeThingstoconsider

or alternatively speak to the Duty Planning Ofcer

whose contact details are at the end of this

document. They should:

Be the smallest possible size and coloured to

blend with surroundings.

Be sited inconspicuously, and should not

normally be installed on building frontages or

roofs.

Have discreetly located feed cables.

Redundant equipment should be removed before

new equipment is installed.

8.5 Replacement windows

Windows are strong visual elements in the streetand can have a signicant impact on character.

In many cases it may be possible to repair existing

windows rather than replace them, and improve

the thermal efciency of original windows by draft

proong or adding secondary glazing.

Try to replicate the original windows as far as

possible in terms of detailing and materials,

opening arrangements and the pattern of glazing

bars.

If you are considering replacing windows and

would like advice on the most appropriate

replacements, please contact the Council's

Conservation Ofcer.

Poorly sited satellite dishes can have a

detrimental impact on the street scene
http://www.planningportal.gov.uk/wps/wcm/connect/Portal2/portal2Site/permission/commonprojects/antenna/guidance#GoodpracticeThingstoconsiderhttp://www.planningportal.gov.uk/wps/wcm/connect/Portal2/portal2Site/permission/commonprojects/antenna/guidance#GoodpracticeThingstoconsiderhttp://www.planningportal.gov.uk/wps/wcm/connect/Portal2/portal2Site/permission/commonprojects/antenna/guidance#GoodpracticeThingstoconsiderhttp://www.planningportal.gov.uk/wps/wcm/connect/Portal2/portal2Site/permission/commonprojects/antenna/guidance#GoodpracticeThingstoconsiderhttp://www.planningportal.gov.uk/wps/wcm/connect/Portal2/portal2Site/permission/commonprojects/antenna/guidance#GoodpracticeThingstoconsider


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9.0 List of Contacts

Duty Planning Ofcer

For general planning advice between 10 am and 4 pm Monday to Friday.

Sycamore House, Waltham Forest Town Hall, Forest Rd, London E17 4JF

Tel: (020) 8496 3000

Email: [email protected]

Conservation Ofcer

For queries related to Conservation Areas or Listed Buildings

Guy Osborne

Sycamore House, Waltham Forest Town Hall, Forest Rd, London E17 4JF

Tel: (020) 8496 6737


Building Control Department

For advice on Building Regulations

Sycamore House, Forest Road, London E17 4JF

Tel: (020) 8496 3000



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London Borough of Waltham Forest

Urban Design Team

Sycamore House

Waltham Forest Town Hall

Forest Road

Walthamstow

London

E17 4JF

Tel: 020 8496 3000

Brief Guide to Home Extensions and Alterations

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