Loft Conversion Cost by Type
Unlike a kitchen or bathroom, loft conversion pricing is driven almost entirely by how much you change the roof structure. Here's what each type typically costs and what it involves:
| Type | Price range | What's involved |
|---|---|---|
| Velux / rooflight | £28,000–£40,000 | No change to the roof profile, rooflight windows fitted into the existing slope. Needs sufficient existing head height, common in pre-1940 Manchester houses |
| Rear dormer | £35,000–£55,000 | A box-shaped extension built into the rear roof slope, adding significant head height and floor space, the most common loft conversion in Manchester's semis and terraces |
| Hip-to-gable | £45,000–£65,000 | Extends a sloped (hipped) side roof out to a vertical gable wall, adding substantial extra space, common on detached and semi-detached houses with a hipped roof |
| Mansard | £55,000–£80,000+ | The rear roof slope is rebuilt to a steep, near-vertical angle, maximising usable space, the most involved conversion, often combined with a hip-to-gable |
Why Roof Type Matters More Than Finish
With kitchens and bathrooms, the finish, worktop material, tile choice, appliance brand, drives a big part of the cost spread. With loft conversions, the structural category you fall into matters far more than whether you choose a budget or premium en suite. A Velux conversion with a luxury finish will still usually cost less than a basic-finish hip-to-gable, because the roof alteration itself is the larger expense.
Velux / rooflight conversions
The simplest and most cost-effective option. No structural changes to the roof profile, just rooflight windows installed in the existing slope. This only works where the existing head height is already sufficient, which is the case in many pre-1940 Manchester properties with steeper traditional roof pitches. Almost always falls under Permitted Development, meaning no planning application is needed.
Rear dormer conversions
The most popular choice across Greater Manchester's semis and terraces. A box-shaped structure is built out from the rear roof slope, adding both head height and usable floor space, typically enough for a double bedroom and en suite. Most rear dormers also fall under Permitted Development, though size limits apply.
Hip-to-gable conversions
Where a property has a hipped (sloped) roof on the side rather than a flat gable end, this conversion extends that slope out to a vertical wall, significantly increasing the usable footprint. Common on detached and semi-detached houses. Often combined with a rear dormer for maximum space, which pushes cost toward the higher end of this band.
Mansard conversions
The most extensive option, the rear roof slope is rebuilt almost vertically, maximising every inch of usable space under the new roofline. This typically requires full planning permission rather than Permitted Development, particularly in conservation areas, which is part of why it's the most expensive category.
What Affects Cost Within Each Category
- En suite vs no en suite — adding a bathroom means new waste runs (often requiring a macerator pump), water supply, and waterproofing, typically adding £6,000–£10,000
- Staircase complexity — a straightforward straight staircase is cheaper than a space-saving or winder staircase needed in tighter Victorian terraces
- Insulation and roof condition — older roof timbers sometimes need reinforcement to meet current building regulations for floor loading, which isn't always visible until work starts
- Number and size of rooflights or windows — more glazing improves natural light but adds to both materials and labour
- Conservation area restrictions — properties in conservation areas across parts of Chorlton, Didsbury and Salford may need full planning permission even for conversions that would normally be Permitted Development, adding time and sometimes design constraints
Why a Loft Conversion Often Beats Moving House
- Typically costs 60–70% less than moving to a larger Manchester property once stamp duty, estate agent fees and moving costs are factored in
- Adds 20–25% to your property's market value on average — more in high-demand areas like Didsbury and Chorlton
- No need to leave the neighbourhood, school catchment, or commute you've already built your life around
How to Get an Accurate Quote
The price ranges above are a genuine starting point, but the only way to get a number you can budget against is a site survey. A structural engineer or experienced project manager needs to assess your roof type, existing head height, joist condition and any conservation area restrictions specific to your property before a fixed price can be confirmed. We provide a free site survey and return a fixed, written quote, not a ballpark estimate. See real completed conversions on our projects page, or read more about the process on our loft conversion service page.