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Service area · London Borough of Lewisham

Architectural Designers in Lewisham

Magna Studio prepares planning and Building Regulations drawings for homeowners across the London Borough of Lewisham. Our typical Lewisham projects are side-return and rear extensions to Victorian terraces in Brockley, Ladywell and Hither Green, dormer lofts on Edwardian houses in Forest Hill and Sydenham, side extensions on 1930s semis in Grove Park and Downham, and sensitive alterations to Georgian houses in Blackheath. Every quote is a fixed fee agreed in writing before we start.

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Planning authority
Lewisham
Decision time
8 weeks statutory
Common work
Rear extension
Quote
Within 24 hours
01Local context

Typical homes we work on in Lewisham

  • Georgian and Regency houses and terraces in Blackheath and around Blackheath Village
  • Victorian terraces and villas in Brockley, Ladywell, Hither Green, Lee and New Cross
  • Edwardian houses in Forest Hill, Sydenham, Honor Oak and Catford
  • 1930s semis and terraces in Grove Park, Bellingham and Downham, including the Downham cottage estate
  • Post-war estates and recent regeneration schemes in Deptford, Lewisham town centre and Catford
  • Converted houses and mansion flats across Brockley, Forest Hill and Sydenham
02Constraints

Planning constraints in Lewisham

What changes the planning route in this area. Always confirm on the council's constraints map before relying on permitted development.

Conservation areas

Lewisham has numerous conservation areas, including large ones at Brockley and Blackheath and others in Forest Hill, Sydenham, Lee Manor, Telegraph Hill and Deptford. Roof extensions and cladding in these areas need planning permission rather than permitted development. Check the council's constraints map for your address before assuming PD applies.

Source · Checked 15 Sept 2026

Article 4 directions

The Brockley conservation area and some others in Lewisham carry Article 4 directions removing permitted development for front alterations, windows, roofs and boundary treatments. Coverage varies by area, so we check the schedule for your street before recommending a permitted development route.

Checked 15 Sept 2026

Alterations and Extensions SPD

Lewisham publishes a supplementary planning document on alterations and extensions setting out expectations for depth, height, roof form, materials and the design of dormers and side extensions. Officers apply it to householder applications, so we design and check against it before submission.

Source · Checked 15 Sept 2026

Ravensbourne, Quaggy and Pool river flood zones

The Ravensbourne, Quaggy and Pool rivers run through Catford, Lewisham town centre, Ladywell, Lee and Bellingham, and land along them falls within Flood Zones 2 and 3. The Thames frontage at Deptford is also Flood Zone 3. Basements and new ground-floor habitable rooms there may need a flood risk assessment.

Source · Checked 15 Sept 2026

Listed buildings in Blackheath and Deptford

Blackheath, Blackheath Park, Deptford High Street and St Paul's Deptford contain many listed Georgian and Victorian buildings. Listed houses need listed building consent for almost any alteration, and extensions to neighbours are judged on their effect on the setting.

Checked 15 Sept 2026

Metropolitan Open Land

Blackheath, Hilly Fields, Beckenham Place Park, Mountsfield Park and the Waterlink Way corridor are Metropolitan Open Land. Houses fronting or backing onto them are judged on the effect of extensions and outbuildings on openness and setting.

Checked 15 Sept 2026

What London Borough of Lewisham planning officers look for

Lewisham's officers apply the Alterations and Extensions SPD fairly closely. Rear extensions deeper than neighbouring precedent, side returns that breach the 45-degree rule and roof extensions in Brockley, Blackheath and other conservation areas are the common refusal reasons; front dormers are resisted almost everywhere. On 1930s streets in Grove Park and Downham side extensions are expected to be set back and subordinate. Lewisham is a busy authority and householder decisions can run past the statutory period. Pre-application advice is available for a fee.

Council links

Extensions and loft conversions in Lewisham

Lewisham runs from the Thames at Deptford through New Cross, Brockley and Lewisham town to Forest Hill, Sydenham, Catford and the 1930s suburbs of Grove Park and Downham, with Georgian Blackheath on its eastern edge. Most of its family housing is Victorian and Edwardian terraces, many converted to flats. The typical brief is a side-return or rear extension to open up a terrace kitchen, a rear dormer for a top-floor bedroom, a side extension on a Grove Park semi, or a garden room.

Brockley and Blackheath are the two areas where the rules change most. Both are large conservation areas, and Brockley’s Article 4 direction removes rights that homeowners elsewhere in the borough take for granted.

Planning constraints in Lewisham

The designations that most often shape a Lewisham project are:

  • Conservation areas at Brockley, Blackheath, Forest Hill, Sydenham, Lee Manor, Telegraph Hill and Deptford, removing PD for roof extensions and cladding.
  • Article 4 directions in Brockley and some other conservation areas removing rights for front and roof alterations.
  • The Alterations and Extensions SPD, which sets depth, height, roof form and materials expectations.
  • Flood Zones 2 and 3 along the Ravensbourne, Quaggy and Pool rivers and the Thames at Deptford.
  • Listed buildings in Blackheath and Deptford.
  • Metropolitan Open Land at Blackheath, Hilly Fields and Beckenham Place Park.

Flats and maisonettes have no householder PD rights, so every extension to a converted house needs planning permission, and the freeholder’s consent as well.

What Lewisham planning officers look for

Lewisham’s officers apply the Alterations and Extensions SPD fairly closely. For rear and side-return extensions they want depth in step with neighbouring precedent, the 45-degree rule respected to neighbouring habitable room windows and eaves kept low near boundaries. For lofts they support rear dormers set down from the ridge and in from the party walls, clad to match the roof; front dormers are refused almost everywhere.

Side extensions on Grove Park and Downham semis should be set back from the front wall with a roof below the main ridge. In Brockley and Blackheath expect detailed comments on windows, brick and boundary treatments. Pre-application advice is available for a fee and is worth using for anything in those two areas.

Our services in Lewisham

Example projects nearby

Guides

Read our guides on extending or converting a loft in a conservation area and permitted development rights in London.

Ready to start in Lewisham? Get an instant estimate: your indicative fee on screen and by email in two minutes, then a written fixed-fee quote within 24 hours.

03Examples

Example projects in and around Lewisham

Site plan of a Beckenham garden showing the 20 m² garden office positioned in the far cornerExample project
Outbuilding / garden roomBeckenham, Bromley

Garden Office in Beckenham, Bromley

Insulated 20 m² garden office with a 2.5 m high flat roof, placed within 2 m of the rear and side boundaries of a suburban garden in Beckenham, Bromley.

Typical route: Permitted development under Class E, proved with a Lawful Development Certificate

04Questions

Planning questions we hear in Lewisham

Do I need planning permission for a rear extension in Lewisham?

Often not. A single-storey rear extension up to 3 m on a terrace or semi (4 m detached) is usually permitted development, extending to 6 m or 8 m under the larger home extension prior approval route. You will need planning permission if your house is a flat, sits in a conservation area with an Article 4 direction such as Brockley, or if the extension exceeds these limits. We check the constraints for your address first.

Can I convert my loft under permitted development in Lewisham?

Yes for most Lewisham houses outside conservation areas, within 40 m³ for a terrace or 50 m³ for a semi or detached house and with no dormer facing the road. In Brockley, Blackheath, Forest Hill and other conservation areas roof extensions need planning permission and are judged against the Alterations and Extensions SPD. We recommend a Lawful Development Certificate for any PD loft.

Is Brockley conservation area different from the rest of Lewisham?

Yes. Brockley is one of Lewisham's largest conservation areas and has an Article 4 direction removing permitted development for many front and roof alterations, so work that would be PD elsewhere in the borough needs planning permission there. Officers expect traditional materials and detailing. We prepare a design and heritage statement with every Brockley application.

How long does Lewisham council take to decide a householder application?

The statutory period is 8 weeks from validation for a householder application or a Lawful Development Certificate, and 42 days for a larger home extension prior approval. Lewisham is a busy authority and decisions can run past the statutory period, so we build that into the programme. The council fee is £528 for a householder application (verify before applying).

05Coverage

Everywhere we work

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