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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, dramatically increasing the usable floor area of your loft. Can be combined with a rear dormer for maximum space.

From £30,000
Timescale: 8–12 weeks

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What is a Hip-to-Gable Loft Conversion?

Many 1930s, 1950s, and 1960s semi-detached and detached homes were built with hipped roofs — roofs that slope on all four sides to a central ridge. While these roofs look attractive, the triangular hip at the side severely limits the usable floor area of the loft space below.

A hip-to-gable conversion solves this by removing the sloped hip entirely and replacing 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 area — substantially more usable space than the original hipped configuration allowed.

Many homeowners choose to combine a hip-to-gable with a rear dormer on the same project. This combination creates a near full-width, full-height loft room spanning the entire footprint of the house. It is one of the most transformative home improvements available to owners of semi-detached properties.

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?

Hip-to-gable conversions are suitable for specific property types. Check the following:

  • 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

Hip-to-gable only. Combined hip-to-gable and rear dormer projects start from £38,000 and deliver the maximum possible loft space.

Build Programme

8–12 weeks

Including gable construction and full internal fit-out to building regs sign-off. Planning and structural work is completed before the build commences.

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 and replaces it with a vertical flat wall called a gable. This extends the internal floor area of the loft from the cramped triangular space under the hip to a full, usable rectangular room. The result is a substantially larger loft space that can comfortably accommodate a bedroom, en-suite, or home office.
Do I need planning permission for a hip-to-gable conversion?
For semi-detached properties, a hip-to-gable conversion to the flank wall (side) typically falls within Permitted Development as long as the new gable is set back from the original eaves line and the total volume added does not exceed 50 cubic metres. For detached homes, similar PD rules apply. However, properties in conservation areas, National Parks, Areas of Outstanding Natural Beauty, or subject to an Article 4 direction will require full planning permission. 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. Many homeowners combine both: a hip-to-gable at the side and a rear dormer give the maximum possible loft space — effectively a full-width room running from the new gable to the rear of the house. The hip-to-gable alone adds significant floor space at the hip end, but combining it with a rear dormer delivers the most 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 because 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. Both elements can still fall within Permitted Development subject to volume limits.
What is included in the cost of a hip-to-gable conversion?
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. We never add charges after the contract is signed unless you request a change to the agreed scope.

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