Loft conversions in London

An extra bedroom and en-suite without losing a metre of garden. Dormer, hip-to-gable and Velux conversions on London terraces and 1930s semis, finished to building regs and signed off.

From £42,000 · typically 8–12 weeks on site

Will your loft actually convert?

The first thing to check is head height. You need roughly 2.2m from the top of the existing ceiling joists to the underside of the ridge for a conversion to work without dropping ceilings below. Take a tape measure up there before you do anything else — if you are close to that number, it is worth a site visit.

The second thing is roof type. Traditional cut roofs with open rafters convert easily. Modern trussed roofs with W-shaped timbers need structural work first, which adds cost but is far from impossible.

The three types we build

Rear dormer

The most common London conversion. A flat-roofed box built out from the rear slope, giving full head height across most of the floor. Usually permitted development on a house, and typically gives you a double bedroom plus an en-suite.

Hip to gable

For end-of-terrace and semi-detached houses with a sloping side roof. The hip is squared off into a vertical gable wall, then usually combined with a rear dormer. It gives the most space of any option.

Velux or rooflight

No structural change to the roof shape, just insulation, floor, staircase and roof windows. The cheapest option by a long way, and the right one where head height is already generous.

Fire safety and the staircase

This is where most DIY loft rooms fail building control and become a problem when you sell. A habitable loft needs a protected escape route: fire doors to every room off the stairwell, mains-wired interconnected smoke alarms, and a compliant staircase with proper headroom. We build to that standard as a matter of course, which is what makes the room count as a bedroom on the survey rather than storage.

Common questions