Hammersmith & Fulham's Mansard Roof SPD is one of the most detailed borough-level design guides for this type of conversion in London. It specifies minimum setbacks from the front parapet (minimum 1.5m on principal elevations), maximum roof slope angles, and required parapet heights. Getting these measurements wrong results in refusal.
This property was in the Shepherd's Bush Conservation Area. The front elevation faces a street of similar Victorian terraces, all of which have existing mansards — which actually helps, as it establishes a character precedent the council can reference when approving new applications.
We prepared the application with detailed sections through the new roof structure, a 3D visualisation showing the proposed mansard in street context, and a heritage statement addressing both the SPD criteria and the conservation area character appraisal. The front mansard slope was set at 72 degrees — the angle that replicates the traditional London mansard profile.
Hammersmith & Fulham determined the application in 13 weeks — longer than the 8-week target, but within the range typical for this borough on conservation area applications. No pre-application advice was required, saving the clients £350 in pre-app fees.
If you have a similar project in Hammersmith & Fulham (W12), Mansard Roof Drawings in Hammersmith & Fulham starts from £1,575. Get a free quote in 60 seconds — we respond within 2 hours.