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Planning11 min read

Southwark Extension Guide: Planning, Costs & Conservation Areas 2025

48 conservation areas including Dulwich Village. Side return £80k-120k, rear £70k-105k. Mix of Victorian terraces (Camberwell, Peckham) and Edwardian semis (Dulwich). South London pricing.

Quick Summary

Conservation Areas: 48 areas covering ~35% of borough (extensive coverage)

Article 4 Directions: Present in several conservation areas including Dulwich

Housing Mix: Victorian terraces (Camberwell, Peckham), Edwardian semis (Dulwich), council estates (Walworth, Elephant & Castle)

Extension Costs: £1,800-2,500/m² (South London mid-range)

Planning Fee: £206 householder + £105 postal/email surcharge (total £311)

Area Variations: Dulwich most restrictive, Peckham Rye moderate, Walworth/Old Kent Road least restrictive

Southwark's Planning Landscape

Southwark is London's most diverse borough for extensions - from affluent Dulwich Village with strict conservation controls to redeveloping areas like Old Kent Road with minimal restrictions. Understanding your specific area is critical.

AreaHousing TypeConservation StatusExtension Difficulty
Dulwich (Village, Wood)Large Edwardian houses, semisMultiple conservation areas
Article 4 directions
⚠️ High - strict controls
Camberwell (Grove, Green)Victorian terraces, some GeorgianConservation areas present⚠️ Moderate-High
Peckham (Rye, Hill)Victorian terraces, inter-warPeckham Hill Street CA⚠️ Moderate
Nunhead, Honor OakVictorian/Edwardian mixLimited conservation areas✓ Moderate-Low
Walworth, Old Kent RoadCouncil estates, modern flatsMinimal conservation coverage✓ Low - easiest

Extension Costs in Southwark

According to TrustedBuilders South London data, Southwark costs £1,800-2,500/m² - standard South London pricing, with Dulwich at upper end and Peckham/Walworth at lower end.

Extension TypeTypical SizeDulwich (High)Camberwell/Peckham (Mid)
Side return10-12m²£60,000-75,000£52,000-65,000
Side return + kitchen10m² ext + 20m² refurb£100,000-130,000£80,000-105,000
Single storey rear (3m)18-22m²£70,000-90,000£60,000-78,000
Single storey rear (6m)36-42m²£90,000-115,000£75,000-95,000
Wrap-around40-50m²£120,000-150,000£100,000-130,000
Two storey rear40-50m²£140,000-180,000£120,000-155,000

Why Costs Vary by Area in Southwark

Dulwich Premium (15-20% Higher):

  • Conservation area requirements mandate traditional materials (adds £8k-15k)
  • Larger properties = larger extension areas = higher total costs
  • High-end finishes expected by local market
  • Premium contractors charge SE21 rates

Camberwell/Peckham Standard Pricing:

  • Mix of conservation and non-conservation properties
  • Modern materials often acceptable outside CAs
  • Competitive builder market (more choice)
  • Standard South London pricing applies

Conservation Areas in Southwark

Southwark has 48 conservation areas - one of the highest counts in London. According to Southwark Council conservation guidance, these areas cover approximately 35% of the borough's residential properties.

Key Conservation Areas for Extensions

Dulwich Village & Dulwich Wood (Strictest)

Coverage: Large Edwardian houses, generous plots, leafy streets

Restrictions: Article 4 directions present, traditional materials mandatory, pitched roofs required

Design Requirements: Arts & Crafts/Edwardian character must be respected, red brick, clay tiles, timber windows

Planning Strategy: Pre-application advice essential (£200-400), expect amendments, use heritage consultant for complex schemes

Camberwell Grove & Camberwell Green

Coverage: Georgian and Victorian houses, elegant terraces

Restrictions: Conservation area controls, some Article 4 directions

Design Requirements: Match existing materials (London stock brick), proportional extensions, traditional detailing

Planning Strategy: Pre-app advised, demonstrate heritage sensitivity, rear extensions more likely approved than visible front/side

Peckham Hill Street & Peckham Rye

Coverage: Victorian terraces, some Edwardian villas

Restrictions: Conservation area designation but less strict than Dulwich/Camberwell

Design Requirements: Traditional materials preferred but some modern acceptable, subservient scale

Planning Strategy: Pre-app optional for standard rear extensions, required for two-storey or unusual designs

Non-Conservation Areas (Easiest)

Includes: Walworth, Old Kent Road, parts of Nunhead, Honor Oak Park

Restrictions: Standard PD rights apply, no conservation constraints

Design Requirements: Modern materials acceptable, contemporary designs approved, flat roofs OK

Planning Strategy: Use PD where possible, planning applications straightforward, faster approvals

Permitted Development in Southwark

According to Southwark's PD technical guidance, standard rules apply outside conservation areas, but several areas have Article 4 directions removing specific rights.

Standard PD Rules (Non-Conservation Areas)

Property TypeSingle Storey Rear (No Prior Approval)Larger Extension (Prior Approval)
Terraced/semi-detachedUp to 3m depth
Max 4m height overall
Max 3m at boundary
Up to 6m depth
£96 fee + £105 postal surcharge
6 weeks decision
Detached houseUp to 4m depth
Max 4m height overall
Max 3m at boundary
Up to 8m depth
£96 fee + £105 surcharge
6 weeks decision

Important: Flats Have No PD Rights

According to Southwark Council guidance, permitted development rights do not apply to flats. If you live in a flat (even ground floor with private garden), any external works require planning permission.

This affects significant portions of Southwark including Elephant & Castle, Walworth, and Old Kent Road where flat conversions are common.

Article 4 Directions Impact

Several Southwark conservation areas have Article 4 directions removing PD rights for:

  • Window and door replacements (must match originals in style and materials)
  • Roof alterations including material changes
  • Painting or rendering external walls
  • Some rear extensions even within standard PD size limits

Check if your property has Article 4 restrictions: Southwark Article 4 Directions Map

Planning Application Process & Fees

Southwark Planning Fee Surcharge

Unique to Southwark: £105 surcharge (plus VAT) for postal and email applications on top of standard planning fees.

Total cost: £206 (householder fee) + £105 (Southwark surcharge) = £311 for most extension applications

Application TypeNational FeeSouthwark SurchargeTotal
Householder (full planning)£206£105£311
Prior approval (larger PD)£96£105£201
Pre-application advice£200-400 (size dependent)N/A£200-400

Planning Timeline

1

Pre-Application (Recommended for Conservation Areas)

Cost: £200-400

Timeline: 4 weeks

Essential for Dulwich, recommended for Camberwell/Peckham conservation areas, optional elsewhere

2

Submit Application

Required Documents:

  • • Location plan (1:1250)
  • • Site plan (1:500 or 1:200)
  • • Existing/proposed elevations and floor plans
  • • Design & Access Statement (conservation areas)
  • • Heritage Statement (if affecting CA character)
3

Validation & Neighbour Consultation

Timeline: 1-2 weeks validation + 21 days consultation

Southwark sends letters to adjoining properties. Expect objections in Dulwich (high owner engagement).

4

Decision

Target: 8 weeks (56 days)

Reality: 8-10 weeks typical, 10-13 weeks for conservation area applications requiring amendments

Area-Specific Design Guidance

Dulwich Extensions

What Dulwich Planners Expect:

  • Materials: Red brick matching existing (£45-55/m²), clay tile pitched roofs (not slate or concrete)
  • Windows: Timber sash or casement painted (not stained), UPVC rejected
  • Roof: Pitched matching existing pitch, flat roofs rarely approved on visible elevations
  • Scale: Extension must be clearly subservient to main house (lower ridge, set back from principal elevation)
  • Glazing: Limit to 50-60% of rear elevation, include solid brick sections

Camberwell/Peckham Extensions

Design Approach:

  • Materials: In conservation areas - match existing brick (London stock or red), outside CAs - modern materials acceptable
  • Contemporary Design: More accepted than Dulwich if well-executed and respects context
  • Flat Roofs: Acceptable outside conservation areas, consider parapet walls inside CAs
  • Glazing: Larger glazed areas approved, popular for side returns opening to garden

Common Extension Types

1. Side Return Extensions (Victorian Terraces)

Typical in Camberwell, Peckham, Nunhead:

  • 10-12m² filling narrow side passage (1.0-1.5m width)
  • Combined with rear extension for open-plan kitchen/dining
  • Conservation areas: planning permission needed even within PD size
  • Cost: £52,000-75,000 extension only, or £80,000-120,000 with kitchen refurb

2. Rear Extensions (Edwardian Semis in Dulwich)

Larger Properties Allow Bigger Extensions:

  • Typical 5-6m depth single storey creates 45-55m² space
  • Planning permission required (Dulwich conservation areas)
  • Cost: £90,000-130,000 depending on spec and materials
  • Often includes bi-fold doors opening to large gardens

Party Walls in Southwark

Terraced housing in Camberwell, Peckham, and parts of Nunhead requires party wall agreements for most extensions:

Extension TypeParty Wall Required?Typical Cost
Side return (on boundary)✅ Yes (one side minimum)£1,200-2,200 per side
Rear extension (within boundaries)⚠️ If foundations within 3m of boundary£800-1,600 per side
Loft conversion✅ Yes (both neighbors)£1,200-2,000 (both sides)

Southwark Council Resources

Planning Portal:

  • Search Applications: southwark.gov.uk/planning
  • Phone: 020 7525 5403 (planning enquiries)
  • Email: planning.enquiries@southwark.gov.uk

Useful Documents:

  • Residential Extensions SPD: Design guidance for all extensions
  • Conservation Area Appraisals: Individual assessments for each of 48 areas
  • Article 4 Directions: Check map on Southwark planning website

Frequently Asked Questions

Why does Southwark charge an extra £105 planning fee?

Southwark charges £105 surcharge (plus VAT) for postal and email applications to cover additional administrative costs. This means householder applications cost £311 total (£206 national fee + £105 Southwark surcharge) compared to £206 in other boroughs. This is unique to Southwark among London boroughs. The fee applies to almost all applications submitted by post or email.

How much does a Victorian terraced house extension cost in Peckham vs Dulwich?

Peckham: side return £52,000-65,000, rear 3m £60,000-78,000. Dulwich: side return £60,000-75,000, rear 3m £70,000-90,000. Dulwich costs 15-20% more due to conservation area requirements (traditional materials), larger property sizes, and premium contractor rates. Both areas use £1,800-2,500/m² range but Dulwich sits at upper end.

Do I need planning permission in Dulwich conservation areas?

Almost always yes for extensions. Dulwich Village and Dulwich Wood conservation areas have Article 4 directions removing many PD rights. Even standard 3m rear extensions that would be PD elsewhere require planning permission. Pre-application advice (£200-400) strongly recommended before paying for full drawings. Traditional materials mandatory: red brick, clay tiles, timber windows.

Which areas of Southwark are easiest for extensions?

Walworth, Old Kent Road, parts of Nunhead, and Honor Oak Park. These areas have minimal conservation coverage, full PD rights apply, modern materials accepted, and planning applications straightforward. However, note that flats (common in these areas) have no PD rights - if you live in a flat, you need planning permission regardless of location.

Should I get pre-application advice in Southwark?

Yes if: (1) Dulwich or Camberwell conservation areas (essential), (2) any conservation area with Article 4 directions, (3) two-storey or unusual extension. Cost: £200-400. No if: outside conservation areas + standard single-storey rear extension within PD limits. Peckham conservation areas: optional but recommended for complex schemes.

How long does planning permission take in Southwark?

Target: 8 weeks (56 days). Reality: 8-10 weeks for straightforward cases outside conservation areas. Dulwich/Camberwell conservation areas: 10-13 weeks typical due to higher scrutiny and frequent request for amendments. Add 4 weeks for pre-app advice. Southwark not notably slower than other London boroughs despite high conservation coverage.

Summary: Extensions in Southwark

Borough Diversity: Southwark has London's widest range - from highly restrictive Dulwich (Article 4 conservation areas) to permissive Walworth/Old Kent Road (minimal restrictions). Know your area before planning.

Conservation Coverage: 48 areas (highest count in London) covering 35% of residential properties. Article 4 directions in several areas including Dulwich. Check map before assuming PD applies.

Cost Range: £1,800-2,500/m² = South London standard. Dulwich 15-20% premium (£80k-130k for side return + kitchen). Peckham/Camberwell mid-range (£80k-105k). Walworth lower end due to minimal conservation requirements.

Planning Fees: Unique £105 surcharge means £311 total for householder applications (highest in London). Factor this into budget.

Bottom Line: Location is everything in Southwark. Dulwich requires heritage sensitivity, traditional materials, pre-app advice. Peckham/Camberwell moderate. Walworth/Old Kent Road straightforward. 65% of borough outside conservation areas has good extension opportunities. Check conservation status and Article 4 directions before starting any project.