Tucked within the London Borough of Southwark across the SE22 postcode, East Dulwich has firmly established itself as one of South East London's most desirable addresses for families and long-term homeowners. The area combines a strong village identity — centred around the independent shops and cafés of Lordship Lane — with some of the finest Victorian and Edwardian residential streets in the capital. From the handsome bay-fronted terraces lining Underhill Road and Whateley Road, to the larger semis and detached homes surrounding Dulwich Park and the well-kept period streets near Honor Oak, East Dulwich offers a quality of housing stock and community feel that consistently attracts homeowners who invest seriously in where they live.
For SE22 homeowners, extending rather than moving is a decision that makes both practical and financial sense. East Dulwich property values have grown steadily and the area's enduring popularity — particularly among families — means demand for well-configured, spacious homes consistently exceeds supply. Whether the aim is a wider ground-floor kitchen and dining room, a side return conversion, or a double-storey rear addition that adds a bedroom and bathroom, a well-designed extension in East Dulwich delivers lasting improvements to how the home functions and a reliable long-term return. This guide is written specifically for East Dulwich homeowners and reflects Buildaway's experience delivering extensions across Southwark, combining transparent 2026 pricing, sound local planning knowledge, and an 18-month labour warranty on every completed project.
How Much Does a House Extension Cost in East Dulwich (2026)?
East Dulwich occupies the mid to upper-mid range of South East London's construction market. The quality of the Victorian and Edwardian housing stock in SE22, combined with consistent local demand for experienced builders and the finish standards expected across the postcode, all shape the cost picture. Below are realistic 2026 mid-market figures:
Single-Storey Rear Extension
- Build-only: £2,600 – £3,500 per m²
- Fully finished with kitchen: £3,500 – £4,700 per m²
- Example: 25 m² kitchen-diner = £65,000 – £87,500 build-only or £87,500 – £117,500 turnkey.
Double-Storey Rear Extension
- Build-only: £2,400 – £3,300 per m²
- Fully finished: £3,300 – £4,500 per m²
- Example: 40 m² across two floors = £96,000 – £132,000 build-only or £132,000 – £180,000 turnkey.
Side Return & Wrap-Around Extensions
A consistently popular choice for East Dulwich's Victorian terrace and semi-detached stock: £2,600 – £3,800 per m², depending on structural requirements, glazing specification, and roof design.
All figures reflect fully compliant, Building Control certified builds meeting Southwark Council's current planning and construction standards.
What Drives the Price Up or Down
- Total floor area — the primary cost variable across all project types; a larger extension footprint increases structural, insulation, and finishing expenditure in direct proportion.
- Structural steelwork — load-bearing wall removal is a standard requirement across East Dulwich's Victorian and Edwardian terrace stock and typically adds £3,000–£7,000 to the overall project cost.
- Roof design and specification — flat roofs with quality membranes and rooflights remain the most affordable option; pitched roofs or lantern-style glazing add to cost but can significantly enhance the natural light and feel of the extended space.
- Glazing and doors — bi-fold or sliding doors opening onto a rear garden are popular across SE22 and add £4,000–£10,000 depending on opening width and frame specification.
- Conservation area requirements — parts of East Dulwich, including streets within the Dulwich Estate and adjacent conservation zones, are subject to Southwark's heritage controls, influencing material choices and design approach.
- Dulwich Estate covenants — a number of SE22 properties fall within the Dulwich Estate, which imposes its own approval requirements on top of Southwark's statutory planning process. This adds a layer of pre-construction engagement that needs factoring into both programme and budget.
- Kitchen and bathroom fit-out — kitchens in the East Dulwich market typically range from £11,000 to £30,000+; bathrooms from £6,500 to £16,000.
- Heating and mechanical upgrades — Megaflo unvented systems or boiler replacements are frequently required when extensions increase the heated floor area or add bathrooms: £3,000–£5,500.
- Site access and logistics — residential parking zones, narrower streets around Lordship Lane, and the density of SE22's housing stock all contribute to site preliminary costs and require careful planning.
Planning Permission & Building Control in East Dulwich
- Permitted Development (PD): Smaller single-storey rear extensions in East Dulwich may qualify under PD rights, provided they meet Southwark's criteria for depth, height, and materials. Properties within conservation areas, those subject to Article 4 Directions, or those within the Dulwich Estate require individual assessment before PD is assumed.
- Neighbour Consultation Scheme: Extensions beyond standard PD depth limits — up to 6 metres for terraced and semi-detached properties, 8 metres for detached — require formal notification to Southwark Council and neighbouring owners before work starts. Buildaway manages this process on your behalf.
- Full Planning Permission: Required for double-storey extensions, proposals with street-facing visibility, front alterations, wrap-around designs, and all projects falling outside PD thresholds.
- Dulwich Estate Approval: Properties within the Dulwich Estate — which covers a significant portion of SE22 — must obtain the Estate's own consent in addition to any statutory planning permission. The Estate's surveyors assess proposals for design quality and compatibility with the Estate's character and covenants. Buildaway has experience coordinating with the Dulwich Estate's approval process and factors this into every relevant project programme.
- Conservation Areas: Southwark's conservation area designations covering parts of East Dulwich require extensions to use materials and designs sympathetic to the original building and the prevailing streetscape. Planning officers assess all applications within these zones for visual compatibility.
- Party Wall Act: The density of terraced and semi-detached housing throughout East Dulwich means the Party Wall etc. Act 1996 applies to the majority of extension projects in SE22. Written notices must be formally served on all affected adjoining owners before any structural or excavation work commences.
- Building Control: Mandatory for all extension types — covering structural integrity, thermal performance, drainage, fire safety, and electrical compliance. Buildaway coordinates with Southwark's building control team and accredited private inspectors as appropriate to each project.
How Long Will It Take?
- Design and planning preparation: 4–10 weeks
- Technical drawings, approvals, and statutory notices: 3–8 weeks (Dulwich Estate consent and conservation area applications may extend this further)
- On-site construction:
- Single-storey: 10–14 weeks
- Double-storey: 14–20 weeks
- Dulwich Estate approval, bespoke glazing, or premium kitchen installations may add two to four weeks to the overall programme.
Typical Full Project Budget Breakdown (30 m² Double-Storey)
| Element | Typical Cost |
|---|---|
| Core structure & shell | £76,000 – £96,000 |
| Windows / doors / glazing | £5,500 – £11,500 |
| Kitchen supply & fit | £11,000 – £28,000 |
| Bathroom fit-out | £6,500 – £15,000 |
| Heating / boiler / Megaflo | £3,000 – £5,500 |
| Flooring & decorating | £6,500 – £17,000 |
| Professional fees & permissions | £3,500 – £9,500 |
| Total realistic range: | £112,000 – £162,000 |
(Dulwich Estate properties, conservation area requirements, or higher-specification finishes can push costs beyond £195,000.)
Why East Dulwich Clients Choose Buildaway
- Southwark and Dulwich Estate knowledge — direct experience navigating Southwark's planning framework, Dulwich Estate approval requirements, and the Victorian and Edwardian housing stock that defines SE22's residential character.
- Fully transparent pricing — detailed, itemised quotations broken down by trade and project stage, with no vague allowances or charges introduced once work is underway.
- 18-month labour warranty — providing East Dulwich homeowners with greater post-completion assurance than the standard defects liability period offered by most comparable local contractors.
- Fully accredited and insured — Gas Safe registered, NICEIC certified, and carrying comprehensive public liability insurance on every project without exception.
- Complete project management — Buildaway coordinates architects, structural engineers, Party Wall surveyors, and all specialist trades from first consultation through to final Building Control sign-off, with clear communication at every stage.