A hip to gable loft conversion replaces the sloping end of a roof with a vertical gable wall built up from the flank of the house, then reroofs the new shape. It is a masonry job as much as a roofing one, and what it buys is head height along the whole side of the loft, which is exactly what a hipped roof denies you. On a semi detached or end of terrace house it is often the difference between an awkward room and a proper one.
Which houses it works on, from a semi to a loft conversion detached house
Any house with a hipped end and a flank wall to build up: semi detached, end of terrace and detached houses. A mid terrace has no hip and cannot use it. On a detached house both ends can in principle be squared off, which doubles the masonry and is rarely worth it compared with a dormer at the back.
What the work involves
The hip is stripped, the flank wall is built up in blockwork or brickwork to form the new gable, and a new roof structure is framed off it and tied into the existing ridge. The roof is then recovered over the new shape, which usually means matching tiles across a large visible area. The scaffold stays up for the whole of it, which is one reason it costs more than a dormer alone.
Why a hip to gable dormer loft conversion is the usual combination
Squaring the end gives head height along the side; a rear dormer gives it across the back. Together they turn the loft into a room with a usable footprint and somewhere sensible for a staircase to land. The combination is a bigger project and the quote should show the two elements separately so you can see what each is buying.
Questions people ask about hip to gable loft conversion
Does it need planning permission?
It uses a share of the permitted development volume allowance for a roof enlargement and is subject to material and set back conditions, so it is often permitted development on a house. Flats, designated areas and houses with rights removed need an application.
Will the new gable match the rest of the house?
It should, and matching brick or render on a weathered elevation is genuinely difficult. Ask what the plan is if a match cannot be found, because the alternative is often rendering the whole flank.
Does the neighbour need to be notified?
If the work is on or against a shared wall, or involves excavation near their foundations, the Party Wall Act applies and notices must be served in good time. On a semi detached house that is the normal case rather than the exception.
What is a double hip to gable loft conversion?
Squaring both ends rather than one. Only a detached house has a hip at each end, so only a detached house can do it, and it doubles the masonry for head height along a second side. It is rarely worth it compared with a dormer at the back, which buys usable floor area more cheaply. A semi detached or end of terrace house has one hip and one flank wall, so the question does not arise.