GS Renovation converts lofts across the London Borough of Harrow, on the interwar semis and larger suburban houses of HA1 through to HA7. The hipped roofs around Pinner and Stanmore respond well to a hip to gable conversion with a dormer behind. We coordinate the structural engineer, build to their design and manage Harrow Council building control.
Hip to gable and dormers on Harrow's semis
The hipped roof on a 1930s Harrow semi slopes away on the side elevation, so the loft narrows to a corridor along the ridge and the useful floor area is small. Building the hip up into a full gable wall in matching brick or tile hanging restores the width, and a dormer on the rear slope then squares off the back for a bedroom and en suite. Hip to gable with a rear dormer runs roughly £55,000 to £80,000 on indicative London ranges for 2026.
These roofs were traditionally cut on site with purlins and struts, which is good news, because the timbers can be reworked around a new floor rather than replaced wholesale. Interwar houses in Harrow usually still carry a cold water tank in the roof, so removing it and switching to a combi boiler or an unvented cylinder is a normal first step. Redundant chimney stacks passing through the loft may need supporting or removing, which is a structural decision, not a preference.
Insulation, ventilation and Harrow Council
A loft that overheats in July and streams with condensation in January has been insulated badly, and Part L and the ventilation requirements exist to stop that. We insulate between and under the rafters to hit the required values without losing more headroom than necessary, maintain a clear ventilation path at the eaves or build a properly detailed warm roof instead, and fit background ventilation and extract to the new bathroom. Harrow building control inspects these details along with the structure.
On consents, semi-detached and detached houses are commonly cited as having a 50 cubic metre permitted development volume allowance, with the conditions on matching materials, obscure glazed side windows and nothing forward of the roof plane. Conservation areas such as those around Harrow on the Hill and Pinner Village remove those rights, as do Article 4 directions. We ask Harrow Council where your house stands before any design money is spent.
- Staircase design to Part K, including the landing below
- Rooflight conversions where the roof line must not change
- Velux and conservation rooflights fitted and flashed
- Structural steel sized by the engineer and set on padstones
- Trussed roofs redesigned before any web is cut
Why Harrow Homeowners Choose GS Renovation
Harrow homeowners choose GS Renovation because a hip to gable rebuilds a corner of your house, and it needs a contractor comfortable with steel, roofing and brickwork rather than a fitter. We coordinate the engineer, prepare your party wall notices, run Harrow Council building control and hand over the completion certificate. Founder Abdelaaziz Saaid has 30+ years of hands-on experience, and we quote free with no obligation.
- New floor structure carried on steel, never on the old ceiling joists
- Aftercare and snagging support once the job is finished
- Interlinked mains alarms fitted and certified
- Party Wall notices prepared for steels bearing into a shared wall
- Fully insured, with cover in place on every site
- Rated 4.9 from 31 reviews on MyBuilder