GS Renovation converts lofts across the London Borough of Hillingdon, from the interwar semis of Ruislip and Uxbridge to the more modern estates in UB7 and UB10. What you can do depends heavily on how the roof was built, and that varies by decade here. We coordinate the structural engineer and manage Hillingdon Council building control.
Cut roofs, trussed roofs and what each allows
An interwar Hillingdon semi has a roof cut on site from rafters, purlins and struts, leaving an open void that converts readily once a new floor and steel are introduced. Houses on the later estates around Hayes and Uxbridge were built with prefabricated trussed rafters, where diagonal webs criss-cross the space and carry the roof loads. Those trusses cannot simply be sawn out. Converting them means the engineer designs a replacement structure of steel beams and new floor joists to take over before anything is cut.
That difference shows in the price and the programme, so we establish which roof you have at the first visit along with the ridge height, which needs to be roughly 2.2m to 2.4m above the existing ceiling joists. On a detached or semi-detached house with generous plot width, hip to gable plus a rear dormer is usually the best value, at roughly £55,000 to £80,000 on indicative London ranges for 2026.
Permitted development and building control in Hillingdon
Detached and semi-detached houses are commonly cited as having a 50 cubic metre volume allowance under permitted development, against 40 for a terrace, subject to the usual conditions on matching materials, no verandas or balconies, obscure glazed side windows and nothing forward of the existing roof plane. Hillingdon Council has conservation areas, including around older parts of Uxbridge and the Grand Union Canal, where those rights do not apply. We check before we design.
Building regulations always apply. That means fire safety under Part B with a protected stair to a final exit and interlinked alarms, stair geometry under Part K, a floor built on engineer-sized joists carried by steel rather than resting on the ceiling joists below, and insulation and ventilation to current standards. We build to the engineer's design, book Hillingdon building control inspections at the right stages and hand over the completion certificate.
- New floor joists independent of the existing ceiling
- Staircase design to Part K, including the landing below
- Rooflight conversions where the roof line must not change
- Rear dormers to win full head height across the new floor
- L-shaped dormers over a rear closet wing
The GS Renovation Difference in Hillingdon
Hillingdon homeowners choose GS Renovation because we survey the roof structure before quoting, so a trussed rafter house does not turn into a surprise halfway through. We coordinate the engineer, install the steelwork, prepare party wall notices for you to serve, and run Hillingdon Council building control to sign-off. Fully insured, one dedicated project manager, and 4.9 from 31 MyBuilder reviews.
- Clean, tidy and reliable tradespeople
- Itemised pricing, so you can see what every stage costs
- Interlinked mains alarms fitted and certified
- Roof type assessed so you get the scheme your house can actually take
- Photographs kept at each stage for your records
- Structural engineer instructed and coordinated on your behalf