Do You Need Planning Permission?

Some house extensions may fall within permitted-development rules, while others will require a planning application.
 

The correct route depends on the individual property and the proposed work.
 

Important considerations include:
 

• the depth and height of the extension;

• whether it is single-storey or double-storey;

• the position of the extension;

• the type of property;

• previous additions;

• whether the property is a house, flat or maisonette;

• whether the building is listed;

• whether the property is within a conservation area;

• whether any additional local restrictions apply; and

• the impact on neighbouring homes.
   

Do not assume that your extension will automatically be acceptable because another property nearby has completed similar work.
 

The planning history, property type and design details may be different.

 

The Dulwich Estate Scheme of Management

Some properties within the wider Dulwich area are covered by The Dulwich Estate Scheme of Management.
 

Where the Scheme applies, alterations and extensions may require separate approval from The Dulwich Estate in addition to any local-authority planning approval, Building Regulations approval or other consent.
 

This can be relevant to projects involving:
 

• rear extensions;

• side extensions;

• loft conversions;

• replacement windows;

• external materials;

• rooflights;

• landscaping;

• boundary treatments;

• new structures; and

• works to trees.
   

The Scheme of Management approval process is separate from the planning process.
 

A project may therefore need to be considered by more than one organisation before construction begins.
 

If your home is within The Dulwich Estate, check the position early so that the design and project programme take account of the additional approval route.

 

Conservation Areas and Character Properties

Dulwich is known for its attractive streets, mature landscaping and varied architectural character.
 

Some homes are within conservation areas or close to listed buildings. In these locations, extensions often require a more sensitive approach.
 

The design may need to consider:
 

• the relationship with the original building;

• the scale of the extension;

• roof form;

• brickwork and external materials;

• window proportions;

• glazing design;

• the effect on neighbouring properties;

• views from the street;

• trees and landscaping; and

• the wider character of the area.
   

This does not mean that a modern extension is impossible.
 

Traditional homes can often work well with contemporary glazing and carefully considered additions, provided the design remains balanced and appropriate.

 

Different Parts of Dulwich May Have Different Requirements

The wider Dulwich area crosses local-authority boundaries.
 

Depending on the property address, your project may fall within the planning area of:
 

• Southwark Council;

• Lambeth Council; or

• Lewisham Council.
   

The planning policies, local guidance and application process should therefore be checked against the specific property address.
 

A project in Dulwich Village may raise different considerations from an extension in East Dulwich, West Dulwich or the surrounding streets.

 

Planning Permission and Building Regulations Are Different

Planning permission considers whether the extension is acceptable in principle.
 

Building Regulations deal with how the extension is designed and constructed, including foundations, structure, insulation, drainage, ventilation and fire safety.
 

Most extensions need Building Regulations approval even where planning permission is not required.
 

Structural calculations may also be needed, particularly where:
 

• walls are being removed;

• steel beams are required;

• the rear wall of the house is being opened up;

• large glazed openings are proposed;

• the roof design is complex; or

• the extension affects the existing structure.
  
   

Party Wall Considerations

Depending on the proposed works, the Party Wall etc. Act 1996 may apply.
 

This can be relevant where you are:
 

• excavating close to a neighbouring property;

• building close to or directly against a boundary;

• working on an existing shared wall;

• inserting beams into a party wall;

• raising or altering a party wall; or

• carrying out structural works that may affect adjoining buildings.
   

Party-wall matters should be considered early enough to avoid unnecessary delays before construction.

 

Trees and Landscaping

Trees and mature landscaping contribute strongly to the character of many Dulwich streets.
 

Before finalising an extension design, consider whether the project may affect:
 

• existing trees;

• tree roots;

• hedges;

• boundary planting;

• garden levels;

• drainage;

• access for construction; and

• the relationship between the extension and the garden.
   

Additional checks may be required where trees are protected or where the property is within a conservation area or The Dulwich Estate.
 

A well-considered design should improve the home without losing the qualities that make the setting attractive.

 

Glazing, Rooflights and Garden Access

Glazing can make an enormous difference to the success of an extension.
 

A poorly considered extension may make the middle of the original house feel darker.
 

A carefully designed extension can create a brighter and more enjoyable living space.
 

Options may include:
 

• sliding doors;

• bifold doors;

• fixed glazed panels;

• steel-look doors;

• rooflights;

• roof lanterns;

• clerestory windows;

• internal glazed doors; and

• picture windows overlooking the garden.
   

The best arrangement depends on the room layout, orientation, garden and architectural style of the property.
 

A large opening is not always the only answer. Sometimes a more balanced combination of doors, windows and wall space will produce a better-looking room that is easier to furnish.

 

Preparing Before You Ask Builders to Quote

It is usually better to obtain clear design drawings before requesting detailed builder quotations.
 

The drawings should normally identify:
 

• the size and shape of the extension;

• the internal layout;

• wall removals;

• window and door openings;

• the proposed roof form;

• drainage considerations;

• structural requirements;

• the intended materials;

• important site constraints; and

• the general scope of work.
   

Without suitable drawings, each builder may interpret the project differently.
 

That makes quotations harder to compare and increases the risk of unexpected extras later.

 

Comparing Builder Quotations

Do not choose a builder based on the headline price alone.
 

Check whether the quotation includes:
 

• demolition;

• excavation and foundations;

• drainage work;

• brickwork and blockwork;

• structural steelwork;

• roofing;

• insulation;

• plastering;

• electrics;

• plumbing and heating;

• glazing and external doors;

• kitchen installation;

• flooring;

• decorating;

• waste removal;

• Building Control inspections;

• scaffolding where required; and

• VAT where applicable.
   

A clear scope of work will help you compare quotations fairly and make better decisions.

 

Professionals You May Need

Depending on the project, you may need support from:
 

• architectural designers;

• planning consultants;

• Building Regulations designers;

• structural engineers;

• Building Control professionals or registered approvers;

• party-wall surveyors;

• builders;

• glazing and door specialists;

• kitchen suppliers;

• electricians;

• plumbers;

• drainage specialists;

• arboricultural consultants;

• project managers; and

• other specialist advisers where required.
   

Some homeowners appoint one main contractor to coordinate the project.
 

Others obtain separate quotations for selected services to maintain more control over the specification and budget.

 

Extensions Across Dulwich and the Surrounding Areas

APN Extensions can help homeowners exploring projects across:
 

• Dulwich Village;

• East Dulwich;

• West Dulwich;

• North Dulwich;

• Dulwich Wood;

• Herne Hill;

• Forest Hill;

• Sydenham Hill;

• Peckham Rye;

• Honor Oak;

• Crystal Palace; and

• surrounding parts of south-east London.
   

Every property should be reviewed on its own merits.
 

The right solution for a Victorian terrace in East Dulwich may be very different from the best approach for a substantial family home within The Dulwich Estate.

 

Planning a house extension in Dulwich?

 

Tell us about your property, the space you need and the type of extension you are considering.

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Where appropriate, APN Extensions may introduce you to relevant independent professionals, consultants and service providers who can help you move the project forward.

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You are under no obligation to appoint any provider introduced through APN.