GS Renovation converts lofts across New Malden, in the 1930s semi-detached and interwar houses that fill KT3 between Kingston and Raynes Park. These roofs are hipped and sit on generous plots, so hip to gable with a rear dormer is the scheme that gives real space. We coordinate the engineer and complete under Kingston Council building control.
Turning a KT3 hipped roof into two rooms
An interwar New Malden semi has its roof hipped on the side elevation, and that slope removes the standing height precisely where a bedroom needs it. Rebuilding the hip as a vertical gable recovers the width for the full depth of the house, and a rear dormer then squares off the back. On the wider plots common in KT3 that combination often yields two bedrooms and an en suite rather than the single room a plain rear dormer would give.
The en suite is worth planning at the outset rather than adding later, because the soil pipe route, the boiler position and the tank removal all interact. Switching from a gravity-fed tank to a combi or an unvented cylinder clears the roof space and improves pressure to a new shower. Indicative London ranges for 2026 put hip to gable with a rear dormer at roughly £55,000 to £80,000, with an en suite adding around £8,000 to £15,000.
Inspections, structure and consents in New Malden
Kingston Council building control inspects at defined stages, and those stages drive our programme: the steel beams and their padstone bearings before anything covers them, the new engineer-sized floor joists that carry the room instead of the old ceiling joists, the fire doors and interlinked alarms forming the protected stair route under Part B, the stair geometry under Part K, and the insulation and ventilation build-up before the plasterboard goes on.
Semi-detached and detached houses have a 50 cubic metre permitted development allowance rather than the 40 given to terraces, subject to matching materials, nothing forward of the roof plane, no balconies and obscure glazed side windows. That still needs checking against conservation area status and any Article 4 direction. A hip to gable also builds new masonry at the shared wall, making the work notifiable under the Party Wall etc. Act 1996, with notice served by you as building owner.
- Mansard conversions where planning will not accept a dormer
- L-shaped dormers over a rear closet wing
- En suite plumbing, drainage and mechanical extraction
- Structural steel sized by the engineer and set on padstones
- Insulation between and over rafters to Part L
Why Choose GS Renovation in New Malden
New Malden families choose GS Renovation because a hip to gable is real structural work and the firm's background is structural. We coordinate the engineer, form the gable and set the steels accurately, plan the tank removal and en suite services into the programme, and take Kingston building control through to certificate. Rated 4.9 from 31 MyBuilder reviews, fully insured.
- Dust screens and floor protection in occupied homes
- Roof made good, leadwork and guttering finished properly
- Materials priced at options, so you choose the finish
- Building control applications and inspections coordinated for you
- Registered in England, Companies House no. 14611254
- Staircase set out to Part K within the space you have