How Much Does a Loft Conversion Cost in the UK?
Real 2026 prices by conversion type, a worked example, and what a loft conversion actually adds to your home's value — not just what it costs to build.
Loft conversion cost by spec level
Spec level and conversion type together decide the final number more than anything else:
Basic (Velux)
- Rooflight windows only
- No structural roof changes
- Needs existing headroom
Standard (Dormer)
- Full-height headroom
- En-suite bathroom option
- The most common UK loft conversion
Premium (Hip-to-Gable / Mansard)
- Maximum usable floor space
- Significant structural work
- Often two rooms plus en-suite
Cost by conversion type
| Conversion type | Typical cost |
|---|---|
| Velux / rooflight | £20,000–£30,000 |
| Dormer (rear) | £35,000–£55,000 |
| Hip-to-gable | £45,000–£65,000 |
| Mansard | £50,000–£90,000 |
How much does a dormer loft conversion cost?
A rear dormer typically costs £35,000 to £55,000, making it the most common loft conversion in the UK by a wide margin. It adds full-height headroom across most of the new floor space, which a Velux conversion can't do, without the extra structural cost of pushing the roofline out sideways (hip-to-gable) or right up to the ridge (mansard). Adding an en-suite bathroom typically adds £6,000–£12,000 to a dormer conversion.
How much value does a loft conversion add?
Typically 15 to 25% of a property's value, though the honest answer is that this varies sharply by region and by whether the loft conversion creates a genuine extra bedroom:
| Region | Typical value uplift |
|---|---|
| London | 15–20% (often £75,000–£150,000) |
| South East | 10–15% (often £40,000–£80,000) |
| Midlands & North | 5–10% (often £15,000–£30,000) |
Lower percentage uplift in the Midlands reflects lower property values overall, not a worse return — a loft conversion is still consistently ranked among the highest-ROI home improvements available, and it's one of the few that adds a genuine extra bedroom rather than just extra floor space.
A worked example: standard dormer conversion with en-suite
A realistic breakdown for a rear dormer loft conversion adding one bedroom and an en-suite, a common project for a Leicestershire semi:
| Item | Estimated cost |
|---|---|
| Structural work (dormer construction, steel beams) | £15,000 |
| Staircase installation | £3,500 |
| Insulation and roofing | £4,500 |
| En-suite bathroom | £7,000 |
| Electrics and heating | £3,500 |
| Windows (dormer and Velux) | £2,500 |
| Flooring and decoration | £3,000 |
| Building control and fees | £1,500 |
| 10% contingency | £4,050 |
| Total | £44,550 |
What affects the price
Property type
1930s semis across Leicestershire typically have straightforward roof structures well suited to a standard dormer conversion. Victorian and Edwardian terraces often have steeper roof pitches, which can favour a hip-to-gable approach depending on the exact roof shape. Detached houses generally have the most flexibility for hip-to-gable or mansard conversions on both sides of the roof.
- Planning permission — most loft conversions fall under Permitted Development if the added roof volume stays under 40m³ (terraced) or 50m³ (semi-detached/detached); dormers on the street-facing roof slope usually need full planning permission
- Structural work — steel beams to support the new floor are near-universal in a loft conversion and are already priced into the figures above, not an extra surprise
- Staircase location — losing space from a bedroom below to fit a new staircase can affect the overall value case, not just the build cost
- Existing roof height — below around 2.2m at the ridge, a Velux-only conversion usually isn't viable and a dormer becomes the practical minimum
Local considerations for Leicestershire homes
Loft conversion costs in Leicestershire and the East Midlands generally sit at or below the UK national average, well under the 20–30% premium seen in London and the South East. The value-uplift percentage is lower here too, for the same reason property prices are lower overall — but a well-executed loft conversion in Hinckley still consistently returns more in added value and usable space than most other home improvements for the same spend.
See our full Loft Conversion Specialists page for Renofox's own service across Hinckley and Leicestershire. Considering a home extension instead of, or as well as, a loft conversion? Or need a bathroom renovation for the new en-suite? We cover all three.
Frequently asked questions
How much does a loft conversion cost in the UK?
Typically £20,000 to £90,000 depending on the type, with a standard dormer conversion averaging around £44,000 to £55,000. A simple Velux or rooflight conversion is the cheapest option, from around £20,000; a mansard conversion is the most expensive, often exceeding £50,000.
How much does a dormer loft conversion cost?
A rear dormer loft conversion typically costs £35,000 to £55,000, depending on size and finish. This is the most common type of loft conversion in the UK, since it adds full-height headroom and usable floor space without the extra structural work a hip-to-gable or mansard conversion needs.
How much value does a loft conversion add?
Typically 15 to 25% of a property's value, though this varies significantly by region. London properties can see a 15 to 20% uplift, the South East 10 to 15%, and the Midlands and North around 5 to 10%. In cash terms this often still exceeds the build cost, especially where the loft conversion adds a genuine extra bedroom.
Do I need planning permission for a loft conversion?
Most loft conversions fall under Permitted Development and don't need planning permission, provided the added roof volume stays within set limits (normally 40 cubic metres for terraced houses, 50 cubic metres for semi-detached and detached houses). Dormers on the principal (street-facing) elevation, conversions in conservation areas, and anything exceeding the volume limits usually need full planning permission.
What's the cheapest type of loft conversion?
A Velux or rooflight conversion is the cheapest, typically £20,000 to £30,000, since it doesn't alter the roof structure — windows are simply fitted into the existing roofline. It only works well where the existing loft already has enough headroom.
How long does a loft conversion take?
A standard dormer loft conversion typically takes 6 to 10 weeks on site, longer for a hip-to-gable or mansard conversion given the additional structural and roofing work involved.
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