The conversion guide / hip to gable
Hip to Gable Loft Conversions
Replace a sloping side roof with a vertical gable to create more full-height space. Often suitable for semi-detached and end-of-terrace houses with a hipped roof.
At a glance / 01
A semi-detached or end-of-terrace house with a hipped side roof
The roofline / 02
The ridge is extended across the sloping hip to a new vertical gable wall. This creates more full-height width at the side of the loft without changing the house's footprint.
Planning / 03
A hip-to-gable, with or without a rear dormer, may be permitted development if the house retains those rights and the whole design meets Class B conditions.
Is your roof suitable?
Is a hip-to-gable suitable for your house?
A hip-to-gable is worth exploring on a semi-detached or end-of-terrace house with a hipped side roof. Not every house of this kind has the right roof or planning position; we check both before proposing a layout.
A hip-to-gable conversion needs an existing hipped side roof. The ridge is extended to a new vertical gable, making the area beneath that side of the roof easier to plan as a room.
The survey also establishes where the new stairs can arrive. We then draw up a layout for your home, rather than assuming the same arrangement will work on every roof.
It may suit
- A semi-detached or end-of-terrace house with a hipped side roof
- A loft where the sloping side limits the proposed layout
- A roof that may also accommodate a rear dormer, subject to survey and planning
Roof form / illustrationRoof anatomy
What changes to the roof?
The ridge is extended across the sloping hip to a new vertical gable wall. This creates more full-height width at the side of the loft without changing the house's footprint.
Every roof is different. We survey the existing structure before recommending a design.
Built by Concept Lofts / Hoddesdon / Hertfordshire
A hip-to-gable on an adjoining house.
Hip To Gable Conversion – Hoddesdon / Hertfordshire
In Hoddesdon, we extended the hipped roof to a new gable and built a rear dormer. The completed loft includes a bedroom, en-suite and dressing space.
Completed project / Hoddesdon / Hertfordshire
View projectThe planning route
Planning and permitted development
A hip-to-gable loft conversion does not always need planning permission. Some houses can use permitted development rights under Class B, but we must check the property's restrictions and the proposed roof design before advising you.
For a hip-to-gable with a rear dormer, both additions are assessed together. The additional roof space from both, plus any earlier roof enlargements, counts towards the same 40m³ limit for a terraced house or 50m³ for other houses. Staying under a volume limit alone does not mean the design qualifies.
Class B / roof enlargement
The main checks, clearly set out.
For a house with roof-enlargement permitted development rights, the complete proposal must meet all relevant conditions:
Total additional roof space, including previous enlargements. These are limits, not automatic entitlements.
- 01
Additional roof space is generally limited to 40m³ for terraced houses or 50m³ for other houses. Previous additions to the original roof count too, whoever built them.
- 02
The enlargement must not rise above the highest part of the existing roof or project beyond the plane of the existing roof slope on the principal elevation where it fronts a highway.
- 03
Exterior materials must be of a similar appearance to the existing dwellinghouse. This does not necessarily require the identical product: visible colour, design and overall finish should relate sympathetically to the house and roof.
- 04
The original eaves must normally be maintained or reinstated, with the nearest edge of the enlargement set back at least 0.2m from them so far as practicable. Relevant hip-to-gable work and enlargements joining the original roof to a side or rear extension have specific exceptions to this eaves rule.
- 05
The enlargement must not extend beyond the outside face of an original external wall, except where it joins the original roof to the roof of a side or rear extension. Minor roof details are treated separately.
- 06
Side-facing windows must be obscure glazed and non-opening unless their opening parts are more than 1.7m above the room floor. Verandas, projecting balconies and raised platforms are not permitted under Class B; a Juliet balcony without a platform can normally qualify if the other rules are met.
These are householder rights for houses, not an automatic route for flats or maisonettes. Class B roof-enlargement rights do not apply on designated land such as conservation areas, and rights can also be removed or restricted by an Article 4 direction or a condition on an earlier permission. Listed buildings have additional controls.
The usual 0.2m setback at the original eaves has a specific exception for relevant hip-to-gable work. That exception does not remove the other Class B conditions.
We consider how the new gable and any dormer will look alongside the existing house. Materials must be similar in appearance, though they need not be the identical product.
Do I still need an application?
Even when full planning permission is not needed, we normally recommend applying for a Lawful Development Certificate (LDC) where appropriate. It formally confirms that the proposed work is lawful under permitted development. It is not planning permission and is not legally mandatory simply because work is PD, but it provides useful evidence for your records and a future sale.
We assess your property and loft design, check the relevant permitted development or planning route, prepare drawings and handle the appropriate council submission as part of our design and planning process. No approval can be guaranteed.
Planning and Building Regulations are separate. For more detail, read our loft conversion planning guide or the GOV.UK householder technical guidance. Rules here describe the general position for houses in England; the exact property and proposal must be checked.
Design decisions
Hip-to-gable with a rear dormer
A rear dormer can add height across the back while the new gable adds width at the side. We plan the two roof changes, stairs and rooms together, then agree the external materials and interior finishes with you.
- 01Choose a gable finish similar in appearance to the existing house
- 02Position rooflights in the remaining slope where they help the room and stairs
- 03If a rear dormer is proposed, design both roof changes and their glazing together
The measured layout may allow a main bedroom, an en-suite, dressing or built-in storage, and rooflights in the retained slope. Your choices and the available space decide the final specification.
Inside the roof
Planning the room around the stairs
The extra full-height width may allow a more useful main bedroom layout. Whether an en-suite or dressing area fits depends on the measured room, the stairs and the space needed for safe access.
We provide free proposed floorplans so you can see how the layout could work before deciding.
From first visit to finish
How we design and build it
- 01 / 06
Free Consultation & Quotation
On-site chat about your ideas and budget, then a transparent quotation with free proposed floorplans.
- 02 / 06
Survey
A detailed measure of your home, taking around 45 minutes.
- 03 / 06
Design, Planning & Approvals
Drawings, 3D model, planning or LDC as needed and structural calcs — handled in-house by our design team.
- 04 / 06
Building Control Approvals
Full plans submitted for building regulations approval.
- 05 / 06
Construction
Typically 5–6 weeks on site, with a full week-by-week schedule shared in advance.
- 06 / 06
Completion & Guarantee
Sign-off, cleanup and your 10 year guarantee.
Good questions
Hip to Gable Loft Conversions, explained.
Can a hip-to-gable be combined with a rear dormer?
Yes. The hip-to-gable extends the roof to the side; a rear dormer can add full-height space across the back. The layout and amount of usable room gained depend on the existing roof and proposed design.
Does a hip-to-gable with a rear dormer need planning permission?
Not always. If the house retains permitted development rights, the whole proposal may qualify under Class B. Both additions and any earlier roof enlargements count towards the same volume limit, and all the other conditions must also be met. We check your property and drawings before advising on the right application.
How long does a hip-to-gable conversion take?
A typical Concept Lofts conversion takes around 5–6 weeks on site. Larger or more complex roofs and the chosen finish can take longer; we agree a project-specific programme after survey and design. Planning and approvals take place before the on-site build.
Explore another approach
A place to start
Find out what your roof can accommodate
Tell us about your house. We’ll look at the roof, talk through your plans and advise on a sensible route forward.
Get a free loft assessmentBook a free consultation for your hip-to-gable conversion
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