L-shape loft + master suite
Wandsworth · Victorian terrace · 12-week build
Brief
A growing family on a quiet Wandsworth street needed a second bathroom and a true master suite. The existing first floor offered three small bedrooms; the loft was unconverted with a high ridge and a closet wing return — textbook L-shape territory.
Challenge
Cubic volume exceeded permitted development. The borough required full planning, with a strict 200mm setback at the eaves and natural slate to the rear dormer to match the conservation-area-adjacent street character.
Solution
Full planning submitted with elevation studies showing the dormer reading as a recessive box behind the existing eaves. Natural Welsh slate on a ventilated batten system, lead flashings throughout. Heavy steel beams to bridge the closet-wing junction. Master suite across the front (full Victorian width), ensuite over the existing first-floor bathroom for short services, second bedroom in the closet wing dormer.
Outcome
Planning approved at 8 weeks first-time, no objections. Site build completed in 12 weeks, two days inside programme. Two snags at handover. Resale agent valued the uplift at £230,000 against £118,000 spend.
Spec
Project specification.
Gallery
Inside the build.
"We expected a war zone. We got a quiet, methodical build with weekly photo updates and a snag list of two items. Worth every penny."
— Sarah & James M., Wandsworth
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 £23,600–£53,100 on a l-shape loft conversion.
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 £118,000.
Want a build like Wandsworth?
Get a fixed-scope quote with the same direct-labour delivery. Senior consultant call within one business hour.
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