Double-Storey Side Extension, Ealing Edwardian Semi
A 44 sqm double-storey side extension delivering a family kitchen-diner downstairs and master suite upstairs on a 1908 Ealing semi.
Brief
A 1908 Ealing semi where a young professional family had outgrown the original cellular ground floor plan and needed both a family kitchen-diner and an additional bedroom suite. The plot had a 3.2m side return — wide enough for a substantial double-storey extension subject to planning approval on a street within the Walpole Conservation Area buffer.
Challenge
Ealing's conservation team flagged early concern that a full-width double-storey side extension would erode the rhythm of original Edwardian semis on the street. The standard 1m first-floor setback was required but the brickwork match also needed to be exact — Ealing officers specifically inspect mortar colour, brick bond and lintel detailing on extensions within conservation area buffers. The household also had a strict 'no live-in renovation' requirement requiring an aggressive programme.
Solution
We commissioned a brick survey of three adjacent semis to identify the exact London stock match (a soft red Fareham stock with Flemish bond) and submitted material samples with the planning application. The first-floor setback was articulated with a stepped brick course shadow gap reading as a deliberate join rather than a flat continuation. Internally a 6.2m steel goalpost frame opened the ground floor for the new kitchen-diner, with a steel ridge beam reframing the existing roof valley to accommodate the new upstairs bedroom. Programme was compressed to 20 weeks with two-shift fit-out and prefabricated kitchen units.
Outcome
Planning approved at 9 weeks first-time with no objections from the conservation team — the brick survey and stepped joint detailing were specifically commended in the officer's report. Site completed in 20 weeks against a 20-week programme. Both party wall awards agreed amicably. Resale agent valued the uplift at £310,000 against £178,000 spend.
Spec
Project specification.
Gallery
Inside the build.
"Ealing's conservation team have a reputation for being tough on materials match. Builderr's brick survey turned what could have been a refusal into a commended approval. The finished extension reads as if the house was built this way in 1908 — and the family lived elsewhere through the build with zero hassle."
— Anika and Tom Sharma, Ealing W5
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 £35,600–£80,100 on a double-storey side extension.
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 £178,000.
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