Planning to extend your home in Wimbledon or the surrounding SW19 and SW20 postcodes? Whether you’re dreaming of a light-filled kitchen-diner near Wimbledon Village, a double-storey rear extension in Southfields, or a stylish wrap-around extension on a Victorian terrace near Haydons Road, knowing the true cost in 2025 is key to budgeting smartly.
This guide is for Wimbledon homeowners — from Merton Park and Raynes Park to Colliers Wood and South Wimbledon — who want transparent costs, expert planning advice, and reliable local insight. It’s based on current South West London market rates and the trusted experience of Buildaway, a reputable construction company known for clear pricing, detailed quotes, and an 18-month labour warranty.
How Much Does a House Extension Cost in Wimbledon (2025)?
Wimbledon’s property market is among South West London’s premium zones — expect pricing that reflects high demand, strong property values, and excellent access to central London. Here are the realistic averages:
Single-Storey Rear Extension
- Build-only: £2,200 – £2,800 per m²
- Fully finished with kitchen: £2,800 – £3,500 per m²
- Example: a 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
Usually priced similarly to single-storey rates: £2,200 – £2,900 per m² depending on structure and glazing.
These reflect the typical mid-market Wimbledon range for quality, fully insured builders delivering high-standard finishes.
What Drives the Price Up or Down
- Size & layout – more floor area equals more foundation, materials, and labour.
- Structural steel (RSJs) – removing internal walls adds £2k–£6k+.
- Foundations & drainage – older Wimbledon properties may have deeper foundations or shared drains.
- Roof & glazing design – flat roofs with skylights are economical; roof lanterns or bifolds add £3k–£8k+.
- Kitchens & bathrooms – kitchens £10k–£25k+, bathrooms £6k–£15k+.
- Heating & plumbing – a Megaflo or unvented system may be required (£2.5k–£4.5k).
- Finishes & carpentry – flooring, bespoke storage, and decorating all impact cost.
- Access & parking – some Wimbledon terraces and conservation areas have restricted parking, increasing logistics costs slightly.
Planning Permission & Building Control in Wimbledon
- Many single-storey rear and side extensions qualify under Permitted Development (PD).
- Full planning is required for double-storey, front, or roof extensions.
- Conservation Areas — especially in Wimbledon Village, Merton Park and South Park Gardens — remove PD rights.
- Building Control sign-off is always necessary for structure, insulation, plumbing, and electrics.
A good contractor or architect can guide you through planning applications, drawings, and structural calculations.
How Long Will It Take?
- Design & planning: 4–12 weeks
- Technical drawings & approvals: 2–6 weeks
- On-site build:
- Single-storey: 10–14 weeks
- Double-storey: 14–20 weeks
- Add time for bespoke glazing, kitchen fit-outs, or external landscaping.
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 |
(High-end designs or bespoke architecture may exceed £150k.)
Why Wimbledon Clients Choose Buildaway
- South West London expertise — experienced with Wimbledon’s large detached homes, terraces, and conservation rules.
- Transparent quoting — staged payments and no hidden costs.
- 18-month labour warranty — longer than most mid-market builders.
- Fully insured & compliant — Gas Safe, NICEIC, and public liability certified.
- Comprehensive project management — Buildaway coordinates trades, schedules, and all Building Control approvals.
Frequently Asked Questions
Do I need planning permission for my Wimbledon extension?
Not always — smaller single-storey rears may fall under PD. Larger or double-storey designs and conservation areas will need full planning.
Can I live at home during construction?
Usually yes, especially for rear extensions, though expect some disruption.
Do I need a new boiler?
If you’re adding bathrooms or significant heating demand, upgrading to a Megaflo or new boiler is recommended.
What guarantee do you provide?
Buildaway offers an 18-month labour warranty on all work for complete peace of mind.
Next Steps for Wimbledon Homeowners
If you’re considering extending your Wimbledon home:
- Book a free home visit to assess space, design options, and budget.
- We can arrange planning and architectural services if you don’t have drawings.
- Receive a clear, itemised quote so you know exactly where your investment goes.
📞 020 8108 0388 📧 info@buildaway.co.uk
Buildaway — trusted by Wimbledon homeowners for elegant extensions, bespoke kitchens, and full home renovations done right.