Hammersmith and Fulham · London
Double-Storey Extension in Hammersmith and Fulham
Period terraces with strong demand for side return kitchen extensions and lofts.
Hammersmith and Fulham
Double-Storey Extension specialists across Hammersmith and Fulham.
We deliver double-storey extension projects across the full Hammersmith and Fulham postcode set — W6, W12, W14, SW6. Period terraces with strong demand for side return kitchen extensions and lofts.
A double-storey extension extends the rear of the house over two floors, adding a kitchen-diner or family room downstairs and a bedroom plus bathroom upstairs. It's the biggest single intervention you can make on a London house without changing the roofline, and the most efficient way to add a bedroom and bathroom alongside ground-floor open-plan living. Common on semis and detached homes in outer boroughs; harder but achievable on terraces with full planning.
Every Hammersmith and Fulham project includes a free desk-based planning assessment before we quote. We know the local planning officers, party wall surveyors and approved inspectors by name.
Costs
Double-Storey Extension cost in Hammersmith and Fulham 2026.
| Configuration | Cost range | Timeline |
|---|---|---|
| Standard double-storey (3m × full width) | £110,000–£150,000 | 16–20 wks |
| Larger double-storey (4m × full width) | £140,000–£180,000 | 18–22 wks |
| Premium double-storey + structural glass + bespoke kitchen | £175,000–£220,000 | 20–24 wks |
Local advantage
Eight years of double-storey extension work in Hammersmith and Fulham.
Familiarity with Hammersmith and Fulham's planning officers, party wall surveyors and approved inspectors cuts weeks off the approval timeline. We deliver consistent quality across all 4 postcodes the borough covers.
Recent Hammersmith and Fulham work
Double-Storey Extension examples.
Builderr vs other London builders.
The construction industry has a wide distribution of operators. Here's what changes between a directly-employed, fixed-scope outfit and the alternatives.
| Criterion | Builderr | Typical London builder | Cowboy outfit |
|---|---|---|---|
| Labour model | Directly employed team (PAYE) | Mixed subcontract gangs | Day-rate cash labour |
| Pricing | Fixed-scope itemised quote | Estimate + provisional sums | Verbal price + variations |
| Design & engineering | In-house architect + SE | Outsourced, separate billing | Builder draws on the back of an envelope |
| Planning + LDC handled | Yes — included in price | Often charged extra | Builder asks you to apply |
| Party wall surveyors | Instructed by us | Your responsibility | Skipped (illegal) |
| Building control | Plans + site inspections booked by us | Building Notice route | Not registered |
| Project management | Dedicated PM, weekly photo updates | Foreman doubles up | Owner-manager juggles 5 jobs |
| Payment schedule | Stage payments against signed-off milestones | Weekly invoices | Cash up front |
| Insurance | £10M PL + 10yr structural warranty | £2–5M PL only | No documented cover |
| Snags at handover | <3 typical | 20–30 typical | Walk-off mid-job common |
| Variation creep | 0% — fixed scope | +15–25% over original quote | +40%+ regularly |
Save £33,000–£74,250 on a double-storey extension in Hammersmith and Fulham.
Industry data (FMB, RICS, Which? Trusted Trader 2024) shows the average London construction project overruns by 18–22% on cost and 25–35% on time. Fixed-scope contracts with a single accountable team eliminate that variance. The savings above assume a typical project at £165,000.
FAQ
Double-Storey Extension in Hammersmith and Fulham.
How much does a double-storey extension cost in Hammersmith and Fulham?+
Double-Storey Extension projects in Hammersmith and Fulham typically cost £110,000–£220,000. Hammersmith and Fulham sits across postcodes W6, W12, W14, SW6; local rates align with the wider London market.
Do double-storey extensions in Hammersmith and Fulham need planning permission?+
Period terraces with strong demand for side return kitchen extensions and lofts. We carry out a free desk-based planning assessment for your specific address before quoting, identifying whether permitted development, prior approval, or full planning applies.
Do you work across all Hammersmith and Fulham postcodes?+
Yes — we deliver double-storey extension projects across all Hammersmith and Fulham postcodes including W6, W12, W14, SW6.
How much does a double-storey extension cost in London?+
Typically £110,000–£220,000 depending on size and spec. A standard full-width double-storey on a Victorian terrace usually runs £130–170k.
Do I need planning permission for a double-storey?+
Almost always yes. PD limits make most useful double-storey extensions impossible without full planning.
Get a Hammersmith and Fulham double-storey extension quote.
Senior consultant call within one business hour. Fixed-scope quote for your Hammersmith and Fulham project — no provisional sums.
Other types in Hammersmith and Fulham
Explore other build types in Hammersmith and Fulham.
Double-Storey Extension across London