Hip to Gable
Hip to Gable Loft Conversions in Bromley
The conversion built for Bromley's interwar semis. Squaring off the sloping side of the roof to turn an unusable triangle into a full-height room.
The Right Conversion for a Hipped Roof
Stand at the end of most residential streets in Beckenham, Shortlands or Bromley Common and you will see the same roof shape over and over: a semi-detached house from the 1920s or 1930s where the roof slopes inward on three sides rather than two. That third slope, the hip, is why the loft feels so cramped. It cuts the usable floor area down to a narrow strip along the middle, and it puts the low point exactly where you would want to stand up.
A hip to gable conversion replaces that sloping side with a vertical wall, built up in brick or hung tile to match the house, so the roof becomes a straightforward pitch. The room underneath goes from a triangle you can only kneel in to something with real width, and it is usually the difference between a box room and a proper double bedroom with an en-suite.
Is Your House a Hip to Gable Candidate?
It is the right conversion if:
- Your roof slopes on the side as well as front and back. That side slope is the hip.
- The house is semi-detached or an end terrace, so there is a side elevation to build up.
- You want more than a single room out of the loft.
It is not the answer if your house is a mid-terrace, because there is no side roof slope to square off. That is a dormer or an L-shaped dormer job. And on a detached house you may have hips on both sides, in which case a double hip to gable is possible but roughly doubles the structural work.
Most hip to gable conversions in Bromley are paired with a rear dormer. The gable gives you the width; the dormer gives you the head height and the floor area across the back. It costs more, and it is usually the version that actually gets built.
What the Work Involves
Structural Design First
A structural engineer sizes the steels that carry the new floor and the altered roof. This is not optional and it is not something to take on trust.
Building the Gable
The hip is stripped back and a new gable wall is built up in matching brick or tile, tied into the existing structure.
Reforming the Roof
New rafters and ridge, tied into the new gable, then felted, battened and tiled to match.
The Floor
New joists spanning onto steels, independent of the ceiling below, so the room carries proper floor loading.
Stairs
Usually rising over the existing staircase. Where the house sits, this is often the single biggest design constraint.
Fit-Out
Insulation, plasterboard, electrics, heating, and building control sign-off at each stage.
Hip to Gable Costs in Bromley
| Conversion type | Estimated cost in Bromley |
|---|---|
| Hip-to-gable | £55,000 – £80,000 |
Figures are estimates for guidance only, based on published 2026 ranges and prices advertised locally. Every loft is different. The only accurate number is a quote from a surveyor who has been up in yours.
Planning Permission for a Hip to Gable
A hip to gable adds volume to the roof, so it falls under Class B of the permitted development rules. That gives you 50 cubic metres on a semi-detached or detached house, and any previous roof enlargement anywhere on the house comes out of that allowance first.
Two things switch it off entirely. Class B does not apply at all in a conservation area, and Bromley has 47 of them. And in the Petts Wood Area of Special Residential Character, an Article 4 direction in force since 19 July 2022 removes Class B rights as well.
The planning guide covers the conditions in full: the 0.2 m eaves set-back, matching materials, obscure glazing on side windows, and why a Lawful Development Certificate is worth having even when you do not need permission.
This is general information, not planning advice. Permitted development rights depend on your specific property, what has already been built, and whether the address falls in a conservation area or under an Article 4 direction. Check your address on Bromley Council's own map, and take professional advice before committing to anything.
Why Start Here
We are Not Quoting You
We do not carry out the work, so we gain nothing from talking you into a bigger conversion than your roof needs. A building company quoting you is in a different position.
Specialists Who Cover Your Postcode
Your enquiry goes to loft conversion companies actually working in your part of the borough and currently taking work, not a national list.
Bromley Rules, Not National Boilerplate
Forty-seven conservation areas and an Article 4 direction that removes rights most guides assume you have. We cover what applies here.
Nothing Owed, Nothing Booked
Quotes are free and there is no obligation at any point. On a job this size, take two or three of them.
Find Out What Your Loft Conversion Would Cost
Tell us about your house and what you want the loft for. We will pass it to loft specialists covering your area, and they will come back to you with a quote. No obligation, no pressure.
Areas We Cover for Hip to Gable Conversions
Hip-to-gable conversions suit the interwar semis that fill this part of the borough. These are the areas where we see them most.
Other Conversion Types
Not sure this is the right conversion for your house? The other types are below, and the types of loft conversion guide compares them properly, including the lofts that cannot be converted at all.