Mews-House Mansard Storey, Marylebone W1

Marylebone, London (W1H)
Prime central London · 2024

The brief

A mews house in the heart of Marylebone needed a full extra floor, a proper master suite, in one of the most constrained building environments in the country. The house had a flat parapet roof with the height to go up, but the location, a narrow mews where scaffolding, deliveries and trades all compete for almost no space, made a conventional site build slow and disruptive.

What we did

We designed and built a new mansard-form storey to sit between the existing parapet walls, architecturally a classic Westminster mansard, but delivered as a brand-new 31 sqm floor rather than a conversion of an existing void. It was engineered and built in our North Yorkshire factory, then craned into place, finished in natural slate on the slopes with a single-ply membrane to the top and lead-clad dormers. The existing vaulted ceiling and the chimney were taken down to suit the new modules, a steel ring beam fitted to engineer’s spec, and a double-winding staircase installed to reach the new floor.

The new storey created a master bedroom with a walk-in dressing room and en-suite, built against approved planning drawings (GA107, November 2023), with Building Control approvals and structural engineering calculations included.

The result

A new top floor that reads as though it has always been part of the streetscape, delivered with factory precision and a fraction of the on-street disruption a traditional build would have caused in a setting this sensitive. A classic Marylebone roofline, a modern build method.