Thinking about extending your home in Greenwich, London SE10? Known for its rich maritime heritage, elegant Georgian and Victorian homes, and riverside charm, Greenwich offers homeowners the perfect mix of history and modern lifestyle. From Greenwich Park and the Royal Observatory to the bustling Greenwich Market and scenic Cutty Sark, it's an area where carefully designed home extensions can add both space and long-term value while respecting its unique architectural character.
This guide is written specifically for Greenwich homeowners — from West Greenwich and Maze Hill to East Greenwich and Blackheath borders — who want up-to-date 2025 price guidance, planning advice, and insights from Buildaway, a trusted South East London construction company with a reputation for transparent pricing, compliance, and quality workmanship backed by an 18-month labour warranty.
How Much Does a House Extension Cost in Greenwich (2025)?
Greenwich falls into an upper-tier South East London price bracket due to its conservation status, heritage buildings, and proximity to Central London. However, with expert planning and management, Buildaway helps homeowners achieve high-quality, value-driven extensions across SE10.
Single-Storey Rear Extension
- Build-only: £2,200 – £2,800 per m²
- Fully finished with kitchen: £2,800 – £3,500 per m²
- Example: 25 m² kitchen-diner = £55,000 – £70,000 build-only or £70,000 – £90,000 turnkey.
Double-Storey Rear Extension
- Build-only: £2,000 – £2,600 per m²
- Fully finished: £2,600 – £3,300 per m²
- Example: 40 m² over two floors = £80,000 – £110,000 build-only or £105,000 – £130,000 turnkey.
Side Return & Wrap-Around Extensions
Typically aligned with single-storey rates: £2,200 – £2,900 per m², depending on glazing, roof type, and structural changes.
These rates reflect the Greenwich and Royal Borough construction market for compliant, high-quality, Building Control-approved projects.
What Drives the Price Up or Down
- Heritage and conservation factors – much of Greenwich is within conservation zones, requiring heritage-sensitive design and premium materials.
- Property age and structure – many homes in West Greenwich and Royal Hill areas require additional structural support.
- Glazing and roof types – skylights and flat roofs are cost-effective; bespoke roof lanterns and bifold doors add £3k–£8k+.
- Kitchens and bathrooms – kitchens typically £10k–£25k+, bathrooms £6k–£15k+.
- Foundations and drainage – properties near the Thames or on sloped ground may need deeper foundations or extra drainage.
- Finishes and joinery – premium finishes to match period detailing increase costs but elevate the result.
- Access & logistics – narrow lanes near Crooms Hill or Royal Hill can add time and delivery costs.
Planning Permission & Building Control in Greenwich
- Permitted Development (PD): Many rear and side extensions qualify under PD if size, height, and materials match existing structures.
- Full Planning Permission: Needed for double-storey extensions, listed buildings, and homes within the Greenwich Conservation Area.
- Building Control: Mandatory for structure, insulation, plumbing, and electrics.
Buildaway regularly collaborates with Royal Borough of Greenwich Council and approved private inspectors, ensuring compliant, efficient approvals. We also assist homeowners with architectural drawings, calculations, and submissions.
How Long Will It Take?
- Design & planning: 4–12 weeks (longer for conservation or listed buildings)
- Technical drawings & approvals: 2–6 weeks
- On-site build:
- Single-storey: 10–14 weeks
- Double-storey: 14–20 weeks
- Add extra time for bespoke glazing, premium kitchens, or custom joinery.
Typical Full Project Budget Breakdown (30 m² Double-Storey)
| Element | Typical Cost |
|---|---|
| Core structure & shell | £70,000 – £85,000 |
| Windows / doors / glazing | £5,000 – £10,000 |
| Kitchen supply & fit | £12,000 – £25,000 |
| Bathroom fit-out | £6,000 – £12,000 |
| Heating / boiler / Megaflo | £3,000 – £5,000 |
| Flooring & decorating | £5,000 – £15,000 |
| Professional fees & permissions | £3,000 – £8,000 |
| Total realistic range: | £100,000 – £135,000 |
(Complex conservation or bespoke design projects can exceed £150k.)
Why Greenwich Clients Choose Buildaway
- Local expertise in heritage homes — we’re experienced with Greenwich’s Georgian, Victorian, and modern properties.
- Transparent quoting — detailed, staged quotes with no hidden extras.
- 18-month workmanship warranty — peace of mind beyond industry standard.
- Fully insured & compliant — Gas Safe, NICEIC, and public liability covered.
- End-to-end project management — we handle everything from design to completion.
Frequently Asked Questions
Do I need planning permission for my Greenwich extension?
Yes, often — particularly in conservation areas or for double-storey extensions.
Can I live in my property while the work is done?
Yes, especially for single-storey projects. We ensure your home remains secure and accessible.
Will I need to upgrade my heating system?
If you're adding bathrooms or large kitchen space, upgrading to a Megaflo or new boiler is often recommended.
What guarantee do you provide?
Buildaway offers an 18-month labour warranty on all structural and fit-out work.
Next Steps for Greenwich Homeowners
If you're planning a home extension in Greenwich, Maze Hill, or Westcombe Park:
- Book a free home consultation with Buildaway to discuss your ideas.
- We can manage everything — from planning and design to full build delivery.
- Get a transparent, itemised quote and realistic project timeline.
📞 020 8108 0388 📧 info@buildaway.co.uk
Buildaway — trusted across Greenwich for compliant, high-quality home extensions that respect heritage and maximise modern living.