Hip to Gable Conversions Explained: Is Your Roof Right for One?

A hip to gable loft conversion is designed for houses with a hipped roof, where the side of the roof slopes inwards as well as the front and back. That inward slope eats into the loft and often leaves no room for a staircase. Building the side up into a vertical gable wall and extending the ridge across turns the loft into a usable space, ready for a bedroom, bathroom or study.

Is your roof right for one?

A hip to gable conversion usually suits:

• Semi detached houses with a hipped roof on the open side, very common in 1920s and 1930s suburbs across London.
• Detached houses, where one or both hips can be converted.
• End of terrace houses with a hipped end.
• Bungalows with hipped roofs, where the loft can become a whole new floor.

Mid terrace houses usually have gable party walls already, so a hip to gable is not needed; a dormer or mansard is the usual choice there.

Hip to gable plus rear dormer

Most hip to gable conversions are combined with a rear dormer. The gable creates width and room for the stairs; the dormer creates head height across the back of the house. Together they can give space for a double bedroom with an en suite, and sometimes a second room.

Planning permission

Hip to gable conversions on houses in England can often be built under permitted development, within the current volume limit of 50 cubic metres for semi detached and detached houses (40 cubic metres for terraced), provided the extension does not go higher than the existing ridge, uses similar materials and meets the other conditions. The new roof volume of the gable counts towards the limit along with any dormer. Conservation areas and properties covered by an Article 4 direction usually need planning permission. A lawful development certificate gives written confirmation before you build.

What the build involves

1. Structural design, new floor joists and usually steel beams.
2. Building regulations approval and, for semi detached houses, party wall notice to the attached neighbour.
3. Scaffolding, removal of the hip, and building the new gable wall in brick or block to match the house, or a lightweight frame with render or cladding.
4. Extending the ridge and roof, building any dormer, and fitting roof lights.
5. Stairs, fire protected escape route, insulation, services and finishes.

How we handle hip to gable conversions on London’s Prestige projects

We assess your roof on site, confirm what permitted development allows, and manage the structural design, building regulations, party wall notices and the build itself. Matching brickwork and roof tiles is something we take seriously, so the new gable looks as though it was always there. See a loft and rear extension delivered together on our Richmond Hill project, find out more about our loft conversion service, and book a site visit to see what your roof could become.