Project Type
Mansard Loft Conversion
Duration
18 weeks
Project Value
£110,000
The Challenge
Westminster City Council's planning policies for St John's Wood Conservation Area are among the most stringent in London. The existing roof had a complex multi-pitch geometry with a valley and a projecting bay, making a straightforward mansard form impossible. Any alteration visible from the public realm was subject to detailed design review. The villa was occupied throughout, with a family in residence.
Our Solution
We worked with an architect specialising in Westminster conservation area applications to design a bespoke mansard form that followed the existing roof geometry rather than imposing a standard box. Zinc standing-seam cladding was selected over lead for the larger panels as it better suited the stucco villa character. Westminster approved the application in 10 weeks. A detailed site-management plan ensured the family's routine was disrupted as little as possible.
Results
- ✓Westminster planning approval in 10 weeks — no objections from conservation officer
- ✓Two new bedroom suites created at loft level, totalling 52m²
- ✓Principal suite with dressing room, en-suite, and Juliet balcony
- ✓Secondary suite with en-suite shower room
- ✓Zinc standing-seam cladding — sympathetic to stucco villa character
- ✓Estimated property value uplift: £240,000
- ✓Project completed with family in residence throughout
Key Features
- ✓Westminster conservation area planning consent
- ✓Bespoke mansard form following complex roof geometry
- ✓Standing-seam zinc cladding to main mansard faces
- ✓Two en-suite bedroom suites at loft level
- ✓Juliet balcony with slim-section frameless glass balustrade
- ✓Internorm triple-glazed dormer windows
Specification
| Item | Specification |
|---|---|
| Mansard cladding | RHEINZINK standing-seam zinc, pre-weathered graphite grey, 0.7mm gauge |
| Dormer windows | Internorm HF 310 triple-glazed timber-aluminium, powder-coated dark grey |
| Structural frame | Bespoke fabricated steel portal frame, designed around complex existing geometry |
| En-suite (principal) | Lapicida Calacatta marble wall and floor tiles, Hansgrohe Axor fixtures, UFH |
| En-suite (secondary) | Porcelanosa large-format stone-effect, thermostatic shower, heated towel rail |
| Staircase | Bespoke oak and steel open-tread staircase with glass balustrade |
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