Written by the Loft Life team, who have priced and built hip to gable loft conversions across London and Kent for more than 25 years. Last updated 20 August 2026. Read time: ~9 minutes.
How much does a hip to gable loft conversion cost? In London and Kent it typically runs between £58,000 and £75,000 plus VAT, depending on the size of the roof, the level of finish, and whether you add an en-suite. A hip to gable sits in the middle of the loft conversion range, dearer than a Velux or a standard dormer, but less than a full L-shape. The exact figure comes from a survey of your own roof.
The quick facts
- Typical cost is £58,000 to £75,000 plus VAT as a London and Kent guide
- Best suited to 1930s semis and other homes with a hipped, sloping side roof
- Adds up to around 20 percent to a property's value, according to Nationwide Building Society research
- Turns the sloping side of the roof into a vertical gable wall, creating a full-height room
- Loft Life gives a fixed price after a free survey, so the quote doesn't move
Is a Hip to Gable Loft Conversion Worth It?
For a house with a hipped roof, it usually is. A hipped roof slopes inward on the side as well as the front and back, which wastes the very headroom a loft needs. Building that slope up into a gable wall is what turns a cramped, angular attic into a room you can stand up and live in. For most 1930s semis and similar homes, it is the most cost-effective way to add a proper double bedroom without extending outward or losing the garden.
It also adds lasting value. Because it creates a genuine extra bedroom, and often an en-suite with it, a hip to gable tends to return a strong share of its cost when you sell. You can see how one comes together on a real project in our hip to gable case study in Beckenham.
What a Hip to Gable Loft Conversion Costs in 2026
The price of a hip to gable turns on three things: how big the roof is, how far you take the finish, and whether a bathroom is part of the plan. The table below sets out realistic guide figures for London and Kent so you can budget before you commit. Treat them as a starting point rather than a quote, because a roof only gives up its true figure once a surveyor has measured it. You can also try the cost estimator on our loft conversion costs guide for an instant indicative range.
| What you get | Guide cost |
|---|---|
| Hip to gable with one double bedroom | £58,000 to £68,000 |
| Hip to gable with an en-suite | £66,000 to £75,000 and above |
| Hip to gable combined with a rear dormer, an L-shape | £65,000 to £90,000 |
Most domestic conversions carry VAT on top of these figures. What moves a hip to gable up or down the range is rarely the shell, which is much the same on any hipped roof. It is the fit-out, the bathroom, the wardrobes, the flooring and the lighting, where the money either stays modest or climbs.
How the Cost Compares to Other Loft Conversions
If you are still deciding on the type of conversion, it helps to see hip to gable next to the alternatives. The figures below are the same indicative London and Kent ranges we use in our estimator, so you can compare like for like, and our London loft conversion cost guide breaks each type down further.
| Conversion type | Indicative cost (plus VAT) |
|---|---|
| Velux | £35,000 to £50,000 |
| Dormer | £50,000 to £65,000 |
| Hip to gable | £58,000 to £75,000 |
| L-shape | £65,000 to £90,000 |
| New build | £45,000 to £70,000 |
A hip to gable costs more than a Velux or a standard dormer because it rebuilds part of the roof rather than working within it. What you get for that is a squarer, larger room, which is why on a hipped house it usually gives the best floor space for the money.
What's Included in a Hip to Gable Loft Conversion Price
A hip to gable is a bigger structural job than it looks, so it pays to know what a quote should carry before you compare two of them. A full price covers the architect's drawings and the structural engineer's calculations, the building control sign-off, the new gable wall and the steel that carries the roof above it, then the staircase, the insulation, the electrics and plumbing, the plastering and decoration, and the scaffold and skips that come with any roof job.
Ours is a single fixed figure from the first drawing to the finished room, party wall notices included where a neighbour shares the wall. A quote that looks cheaper on paper has usually left one of those lines out, and they tend to reappear later as extras. We would rather show you the whole cost at the start than hand it to you at the end.
What Drives the Cost of a Hip to Gable Loft Conversion
The single biggest variable is the gable wall itself. A wide semi needs more brickwork, and more steel to carry the roof, than a narrow one, and that structural work is the part of a hip to gable you cannot trim. After the structure comes the finish, which can push the cost of an identical shell up by half depending on how far you take it. A bathroom brings its own plumbing and tiling. Access plays a quiet part too, because a house with no side return means every tile and every length of steel is carried up through the scaffold by hand, which adds labour to the bill.
Location makes less difference than people expect. A hip to gable costs much the same whether the house sits in Bromley, Beckenham, Croydon, Dulwich, Greenwich, Orpington or Sidcup. What changes from street to street is the roof and the access, which is why we price every job on its own survey rather than a postcode.
How to Keep Your Hip to Gable Cost Down
You do not have to spend at the top of the range to get a room you are proud of. The structure is fixed, so the savings come from the finish. Choosing a good-value bathroom suite over a designer one, standard fitted wardrobes over made-to-measure joinery, and holding the electrics to what you actually need will all bring the figure down without touching the quality of the build.
The other saving is planning the layout properly before work starts. Changes made once the scaffold is up are where budgets slip, so time spent at the design stage tends to pay for itself. And a fixed price from a specialist who has built hundreds of these is worth more than a low estimate that grows, because you can plan around it with confidence.
Hip to Gable vs Dormer: Which Costs More?
The two are often weighed against each other, because many homes could take either. A standard dormer conversion extends one part of the roof and comes in a little cheaper, at £50,000 to £65,000. A hip to gable rebuilds the sloping side of the roof, which is more structural work, but on a hipped house it unlocks far more usable floor because it squares off a corner a dormer alone would leave sloping. The honest comparison is not the headline price but the cost for each usable square metre, and on a hipped roof the hip to gable usually comes out ahead.
Frequently Asked Questions
How much does a hip to gable loft conversion cost in London?
In London and Kent, a hip to gable generally lands between £58,000 and £75,000 plus VAT. Where you fall in that band comes down to the width of the roof and how you finish it: a plain, well-built room at the lower end, and a fully fitted suite with an en-suite nearer the top. The only figure you can bank on is the fixed price we give after the survey.
Do you need planning permission for a hip to gable loft conversion?
Often not. A hip to gable on a house with permitted development rights usually goes ahead without a planning application, though conservation areas, flats and already-extended homes can change that. We confirm your position at the survey and take care of whichever consent applies, from a lawful development certificate to a full application.
Does a hip to gable loft conversion add value?
It is one of the better-returning jobs you can do to a hipped house, because it adds a real bedroom rather than reworking space you already have. Nationwide Building Society has put the uplift from adding a loft bedroom and bathroom at roughly a fifth of a home's value, though your street and its ceiling price decide the exact number.
How long does a hip to gable loft conversion take?
Reckon on six to eight weeks on site once the scaffold is up, with a couple of weeks of drawings and approvals before that. A larger roof or an added en-suite stretches it a little. You will have a week-by-week timeline in hand from the survey.
Get a Fixed Price With a Free Survey
Guide figures get you a budget, but a hip to gable is enough of a structural job that the honest number only comes from seeing your roof. The free survey measures the gable, checks whether an en-suite will fit, settles the planning route, and gives you one fixed price for the whole conversion.
Fixed means fixed. After we have surveyed and quoted, that figure is the figure, so nothing creeps onto the final bill. If your roof turns out to be simpler than most, good. If the structure or the access asks for more, you will hear it at the survey, not once the scaffold is up.
There is no obligation either way. As a family-run loft conversion specialist in Bromley, we have been building hip to gables across London and Kent for more than 25 years, every one backed by a 10 year guarantee. Call 0800 028 0099 or use our contact page to book. You can also read the full hip to gable service page or check the areas we cover.