Mansard master suite
Islington · Conservation area · 14-week build
Brief
Islington Victorian terrace in conservation area. Owners wanted a true master suite at the top of the house — bedroom, walk-in wardrobe, ensuite — replicating the spec of their previous flat in Marylebone.
Challenge
Conservation area dictating mansard form, slate finish, ridge height matching neighbouring approved mansards. Tight rear yard with no crane access; all steels delivered through the front door and carried up.
Solution
Pre-app with Islington conservation team confirmed Welsh slate at 500 × 250mm and parapet height to align with the adjoining property's existing mansard. Steels lifted through the front via custom gantry over 2 days. Master bedroom across the rear, walk-in wardrobe in the front eaves, ensuite centrally placed over existing bathroom for short services.
Outcome
Planning + conservation consent approved at 11 weeks. Build completed in 14 weeks. Featured on neighbour's social media as 'how a mansard should be done'. Resale agent estimated +£270,000.
Spec
Project specification.
Gallery
Inside the build.
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 £27,200–£61,200 on a mansard 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 £136,000.
Want a build like Islington?
Get a fixed-scope quote with the same direct-labour delivery. Senior consultant call within one business hour.
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