GS Renovation works across the borough of Wandsworth, and lofts here divide sharply. The red-brick mansion blocks and purpose-built period flats of SW11, SW12 and SW18 usually cannot be converted at all. The Victorian houses on the surrounding streets usually can. We tell you which you own at survey, then build under Wandsworth Council building control.
Mansion blocks and period flats: the honest answer
If you own a flat in a mansion block or a purpose-built period building, the roof is not yours. It is retained by the freeholder along with the airspace above it, and converting it means acquiring that airspace and obtaining formal consent before any design is worth paying for. Add a communal escape stair, shared structure serving several flats below and a block insurer with a view, and for most mansion block owners a loft conversion is simply not possible.
What we do in these buildings instead is substantial in its own right: internal structural alterations with engineer-designed steel where the structure and the lease permit, reconfiguring the flat layout, forming en suites, improving fire and acoustic separation, and full refurbishment. All of it is building regulations work coordinated with Wandsworth Council building control. If your freeholder or managing agent confirms the airspace is available, we will look at the roof with you properly.
Houses across SW11 to SW18
On a whole Victorian or Edwardian house in the borough, the standard schemes apply. A rear dormer squares off the back slope, and an L-shaped dormer over the closet wing gives enough width for a bedroom plus a shower room. Ridge height of roughly 2.2m to 2.4m is the threshold that decides whether the conversion works without lowering ceilings below. Indicative London ranges for 2026 put those schemes at roughly £45,000 to £65,000 and £55,000 to £80,000.
Permitted development may allow 40 cubic metres on a terrace and 50 on a semi or detached house, but Wandsworth's conservation areas remove those rights on many streets, so the designation is checked first. Building control covers the protected stair route with fire doors and interlinked alarms, Part K stair geometry, engineer-sized floor joists on steels bearing on padstones, and Part L insulation. Party wall notice is served by you as building owner where those steels enter a shared wall.
- Building control inspections booked at floor, steel and completion
- Hip to gable conversions on semi-detached and end terrace roofs
- L-shaped dormers over a rear closet wing
- Structural steel sized by the engineer and set on padstones
- Velux and conservation rooflights fitted and flashed
Why Wandsworth Homeowners Choose GS Renovation
Wandsworth clients come to GS Renovation for a clear answer on whether the roof above them can be converted at all, and a properly run project where it can. We coordinate the engineer, build the steelwork and floor structure to specification, prepare your party wall detail and manage Wandsworth building control. Fully insured, 4.9 from 31 MyBuilder reviews, 30+ years of founder experience.
- Honest answer at survey if your roof will not take a conversion
- Aftercare and snagging support once the job is finished
- Party Wall notices prepared for steels bearing into a shared wall
- Rated 4.9 from 31 reviews on MyBuilder
- Clean, tidy and reliable tradespeople
- Roof made good, leadwork and guttering finished properly