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Trusted Loft Conversions
Hip-to-gable loft conversion on a semi-detached house
Ideal for Semi-Detached Homes

Hip-to-Gable Loft Conversion Specialists

A hip-to-gable loft conversion costs between £30,000 and £50,000 in the UK and is suited to semi-detached or detached homes with a hipped roof.

A hip-to-gable conversion replaces the sloping end of your hipped roof with a full vertical gable wall. As a result, the usable floor area of your loft increases dramatically. Better still, you can combine it with a rear dormer for the maximum possible space.

From £30,000
Timescale: 8–12 weeks

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What is a Hip-to-Gable Loft Conversion?

A hip-to-gable loft conversion squares off a sloping roof end to create a full, usable room. Many 1930s, 1950s, and 1960s semi-detached and detached homes were built with hipped roofs. These roofs slope on all four sides to a central ridge. They look attractive, but the triangular hip at the side severely limits the floor area of the loft below.

A hip-to-gable conversion solves this. We remove the sloped hip entirely and replace it with a new vertical gable wall, built out to the original eaves line. The result is a squared-off loft with a full rectangular floor. In practice, that means substantially more usable space than the original hipped roof ever allowed.

Many homeowners go further and combine a hip-to-gable with a rear dormer on the same project. This pairing creates a near full-width, full-height loft room across the entire footprint of the house. As a result, it ranks among the most transformative improvements available to semi-detached homeowners.

Key Benefits of a Hip-to-Gable Conversion

Substantial Space Gain

Replacing the hip creates a full rectangular room — the difference in floor area is dramatic.

Works on Most Semis

Designed specifically for semi-detached and end-of-terrace homes with hipped roofs.

Combinable with Dormer

Pair with a rear dormer to maximise headroom and floor space across the entire loft.

Often Permitted Development

Many hip-to-gable conversions on semis qualify under PD rules — no planning fees.

Is a Hip-to-Gable Conversion Right for My Home?

A hip-to-gable conversion suits any home with a hipped roof end, which usually means a semi-detached, end-of-terrace, or detached house. Mid-terraces do not qualify, since they have no hip to convert. Run through the checklist below to see if your property is a good fit.

  • Semi-detached house — the most common and straightforward case
  • End-of-terrace house with a hipped end gable
  • Detached house with hipped roof on one or both ends
  • Ridge height of at least 2.2 m above existing joists
  • Property NOT a mid-terrace (mid-terraces cannot do hip-to-gable)
  • NOT in a conservation area under Article 4 direction (requires full planning — we handle this)

Not suitable for mid-terrace properties

Mid-terraced houses are attached on both sides and do not have a hipped end that can be converted. If you have a mid-terrace, a dormer or mansard conversion may be more suitable — we can advise on survey.

What's Included in Every Hip-to-Gable Conversion

Free site survey and feasibility check
Architectural drawings and planning documentation
Permitted Development check or full planning application
Building regulations submission and approval
Structural engineer calculations
All scaffold, materials, and plant hire
Demolition of existing hip structure
New gable wall construction (blockwork or timber frame)
Roof ridge extension and re-tiling to match
Internal insulation, floor, and first-fix electrics
New staircase and fire-rated landing door
Final clean, snagging, and building regs certificate

Typical Cost and Timescale

Cost Guide

From £30,000

A hip-to-gable conversion starts from £30,000 on its own. For the most space, combine it with a rear dormer; those projects start from £38,000 and deliver the maximum possible loft area. Your final figure depends on size, finish, and access, which we confirm on survey.

Build Programme

8–12 weeks

Most hip-to-gable conversions take 8 to 12 weeks on site, covering gable construction and the full internal fit-out to building regs sign-off. We complete all planning and structural work first, so the build runs without delay once we start.

Fixed-price quotes only — no hidden extras.

Frequently Asked Questions

What exactly is a hip-to-gable loft conversion?
A hip-to-gable conversion removes the sloping 'hip' at the end of a hipped roof. In its place, we build a vertical flat wall called a gable. This squares off the loft, turning the cramped triangular space under the hip into a full, usable rectangular room. As a result, you get a substantially larger loft with comfortable space for a bedroom, en-suite, or home office.
Do I need planning permission for a hip-to-gable conversion?
Usually not, if you own a semi-detached house. A hip-to-gable conversion to the flank (side) wall typically falls within Permitted Development, so you won't need a planning application. Two conditions apply: the new gable must be set back from the original eaves line, and the total volume added must not exceed 50 cubic metres. Similar PD rules apply to detached homes. However, properties in conservation areas, National Parks, Areas of Outstanding Natural Beauty, or subject to an Article 4 direction will require full planning permission. That is why we carry out a PD eligibility check on every survey.
What is the difference between a hip-to-gable and a dormer conversion?
A dormer adds a box-shaped extension to the rear slope of the roof, while a hip-to-gable replaces the sloping end hip with a vertical gable wall. On its own, a hip-to-gable adds significant floor space at the hip end. Many homeowners combine both for the best of each. Together, the side gable and the rear dormer give a full-width room running from the new gable to the back of the house. As a result, this pairing delivers the most floor space and headroom across the entire conversion.
Can I combine a hip-to-gable with a rear dormer?
Yes — and this combination is one of the most popular choices for semi-detached homeowners. It maximises the usable floor area and standing headroom across the entire loft space. The hip-to-gable creates a full gable wall at the side, while the rear dormer adds height and floor space at the rear. Together, they typically create a full-width room with space for a bedroom and en-suite. Better still, both elements can still fall within Permitted Development, subject to volume limits.
What is included in the cost of a hip-to-gable conversion?
Everything from survey to sign-off. Our fixed-price quote includes: free site survey; architectural drawings; PD check or planning application; building regulations submission; structural engineer calculations; all scaffold, materials, and labour; demolition of the hip and construction of the new gable; internal finishing to first-fix stage (walls, floor, insulation, electrics); new staircase and fire doors; and building regs sign-off certificate. Crucially, we never add charges after you sign the contract unless you request a change to the agreed scope.

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