GS Renovation builds loft conversions in Isleworth, on the Victorian and Edwardian terraces and period homes between the London Road and the river. Closet wings, decent ridge heights and conservation areas near Syon Park all shape what is possible. We handle the engineer, the steelwork and Hounslow Council building control from survey to certificate.
Reading a TW7 roof before anything is drawn
The measurement that decides the project is taken from the top of the existing ceiling joists to the underside of the ridge, and you want roughly 2.2m to 2.4m. That allows for a new floor structure, insulation above and below the rafters, and a finished headroom people can live with. Isleworth's older terraces usually have it. Where a rear closet wing survives, an L-shaped dormer takes in the main slope and the wing together, which is the difference between a double bedroom with a shower room and a single box.
If the ridge is tall and you want to keep the cost down, a rooflight conversion changes nothing outside and comes in at roughly £30,000 to £45,000 on indicative London ranges for 2026. A rear dormer sits at roughly £45,000 to £65,000 and the L-shaped version at roughly £55,000 to £80,000. Adding an en suite is roughly £8,000 to £15,000 more. We price the version your roof genuinely supports rather than the one that reads best in a brochure.
Hounslow Council and the regulations that always apply
Loft conversions often qualify as permitted development, working within the commonly cited 40 cubic metres for a terrace and 50 for a semi or detached house, plus the attached conditions on materials, roof plane, balconies and side window glazing. Isleworth has conservation areas covering its older riverside streets, and inside them, on listed buildings, or under an Article 4 direction, those rights do not exist. Hounslow Council confirms the designation for your address and we check it before design work begins.
Building regulations are separate and unavoidable. The fire strategy under Part B means a protected stair route with fire doors and interlinked alarms, and on a new third storey usually a protected stairwell running to a final exit. Part K governs the stair geometry. The new floor is carried on steel spanning between the party walls, sized by the engineer and bearing on padstones. Cutting that steel into a shared wall is notifiable, and the notice is served by you rather than by your contractor.
- Hip to gable conversions on semi-detached and end terrace roofs
- Protected stair enclosure and fire doors to Part B
- Party Wall notices prepared for the building owner to serve
- Rooflight conversions where the roof line must not change
- Mansard conversions where planning will not accept a dormer
Why Isleworth Homeowners Choose GS Renovation
Isleworth owners choose GS Renovation because the loft arrives as one job rather than three: engineer coordination, structural steel and roof works, then the stair, en suite and finish, all inspected by Hounslow Council building control. Founder Abdelaaziz Saaid brings 30+ years of hands-on experience to TW7 roofs. Fully insured, with quotations that are free and carry no obligation.
- Straight advice on what is and is not worth spending money on
- Photographs kept at each stage for your records
- Building control applications and inspections coordinated for you
- Clean, tidy and reliable tradespeople
- Roof type assessed so you get the scheme your house can actually take
- Water tank removed and the system converted where it blocks the space