Rear dormer loft conversion
A third bedroom and en suite built into an unused roof void, with the dormer designed to sit correctly on a tall villa in a conservation area.
- Property
- Mid-Victorian semi-detached villa
- On site
- 11 weeks
- Completed
- February 2026
- Value band
- £45,000 to £55,000
A growing family in a two bedroom villa with a large and completely unused roof space. The constraint was the street: Brockley Conservation Area, tall houses, and a roof line visible from a long way down the road. A standard full-width box dormer would have been refused, and would have deserved to be.
What we did
A rear dormer set 500mm in from each party wall and 300mm below the ridge, with the cheeks clad in standing seam zinc rather than tile hanging. It reads as a considered addition rather than a bolted-on box, and it kept the application straightforward.
Structure
New floor joists spanning onto twin steels bearing on the party walls, so the new floor loads the walls rather than the ceiling below. The original lath and plaster ceiling downstairs survived the job intact, which does not always happen.
The staircase
The hardest decision in the project. Running the new flight over the existing stairwell would have cost the landing and made the second bedroom door unusable. We turned it through ninety degrees against the party wall instead, and found the head height with a small ceiling drop over the bottom three treads.
Fire and comfort
Fire doors to every room off the stairwell, mains-linked interlinked alarms and thirty minute floor construction. Insulated between and over the rafters with a ventilated void above, so the room is usable in July.
A nineteen square metre double bedroom with an en suite shower room, and a roof line the conservation officer signed off first time.
Other houses we have worked on
Tell us what you are trying to do with the house.
We will come out, measure up and tell you honestly whether it works. The site visit and the written quotation are free, and there is no obligation attached to either.