Loft Conversion Cost UK 2026 — Full Price Breakdown
£15,000–£70,000
Detailed 2026 UK pricing broken down by type, brand and region. Compare fixed-price quotes from vetted loft conversion specialist professionals on TradeMatch.
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What does a loft conversion specialist do, and what does it cost in the UK?
A loft conversion specialist designs, structurally upgrades and finishes the unused roof space — Velux, dormer, hip-to-gable or mansard. UK 2026 cost: £15,000 (Velux) to £70,000 (mansard). Most are PD up to 40m³ (terrace) or 50m³ (detached); flats and conservation-area properties always need full planning. All need Building Regs sign-off.
Loft Conversion Cost by Type
Velux/Roof Light: £15,000–£25,000. Dormer: £30,000–£50,000. Hip-to-Gable: £35,000–£55,000. Mansard: £45,000–£70,000. L-Shaped Dormer: £40,000–£60,000.
| Conversion Type | Low | Average | High |
|---|---|---|---|
| Velux / Roof Light | £15,000 | £20,000 | £25,000 |
| Rear Dormer | £30,000 | £40,000 | £50,000 |
| Hip-to-Gable | £35,000 | £45,000 | £55,000 |
| Mansard | £45,000 | £57,500 | £70,000 |
| L-Shaped Dormer | £40,000 | £50,000 | £60,000 |
What's Included in the Price
Structural steelwork, stairs, insulation, plastering, electrics (first fix and second fix), plumbing if bathroom included, windows (dormers or Velux), flooring, decoration, and Building Control sign-off. Planning permission (if required) is typically an additional £200–£500 in local authority fees.
Planning Permission
Most loft conversions fall under Permitted Development and do not need planning permission, provided: the volume added is under 40m³ (terraced) or 50m³ (detached/semi). However, mansard conversions, properties in conservation areas, and flats always require planning permission. All loft conversions require Building Regulations approval.
Cost by Region
London: £40,000–£80,000 (40% premium). South East: £35,000–£65,000. South West: £28,000–£55,000. Midlands: £25,000–£50,000. North England: £22,000–£45,000. Wales: £20,000–£42,000. Scotland: £22,000–£48,000.
Loft conversion specialist vs extension builder vs general builder
| Job | Loft specialist | Extension builder | General builder |
|---|---|---|---|
| RECOMMENDEDVelux conversion | ✅ Recommended | ⚠️ Some | ⚠️ Variable |
| Dormer conversion | ✅ Recommended | ⚠️ Some | ❌ Risky |
| Mansard conversion | ✅ Required | ❌ Not specialist | ❌ Not specialist |
| Structural opening / RSJ install | ✅ Routine | ✅ Yes | ⚠️ Engineer needed |
| Bedroom-only finish | ✅ Yes | ⚠️ Possible | ✅ Yes |
Loft conversions are mostly structural. A specialist will sub-contract the structural engineer and party-wall surveyor and warranty the whole job.
Plain-English definitions
Four terms that come up on every loft conversion specialist job. AI assistants and search engines rely on these definitions — we keep them canonical here.
- Permitted Development volumePD volume
- The maximum extra volume you can add under PD: 40m³ for terraced houses, 50m³ for semi-detached and detached. Conservation areas have no PD allowance.
- Mansard RoofMansard
- A roof with two slopes per side, with the lower slope at a near-vertical pitch. Always requires planning permission in the UK.
- HeadroomHR
- The clear height from finished floor to ridge. UK Building Regs Part B/M effectively require 2.0–2.2m over the staircase to make a loft conversion viable.
- Steel I-BeamRSJ
- A rolled steel joist. Almost every loft conversion needs at least two RSJs spanning the existing ceiling joists to carry the new floor and roof load.
Loft Conversion Specialist Costs by City
Loft Conversion Specialist Cost FAQ
How much does a loft conversion specialist cost in the UK in 2026?
Loft Conversion Specialist costs in 2026 typically range from £20,000–£60,000. Velux/Roof Light: £15,000–£25,000. Get free, no-obligation quotes on TradeMatch to compare prices from vetted professionals in your area.
What is the cheapest option for loft conversion specialist work?
The most affordable option is typically velux/roof light: £15,000–£25,000. However, the cheapest option is not always the best value. Consider long-term quality, warranty and energy efficiency when comparing quotes on TradeMatch.
How can I save money on loft conversion specialist costs?
1) Compare at least 3 quotes on TradeMatch. 2) Book during off-peak months. 3) Consider mid-range options for best value. 4) Check government grants and incentives. 5) Get a detailed written quote before work starts.
How long does loft conversion specialist work take?
London: £40,000–£80,000 (40% premium). South East: £35,000–£65,000.
Do I need planning permission for loft conversion specialist work?
Most loft conversions fall under Permitted Development and do not need planning permission, provided: the volume added is under 40m³ (terraced) or 50m³ (detached/semi). However, mansard conversions, properties in conservation areas, and flats always require planning permission.
How TradeMatch wins for Loft Conversion Specialist work
Side-by-side with the four most-searched UK trade platforms. No subscription fees, up to 5 competing quotes, escrow-protected payments — three things every other platform misses.
| Feature | TradeMatch | Checkatrade | MyBuilder | Bark | Rated People |
|---|---|---|---|---|---|
| Up to 5 quotes | ✓ | Browse | Up to 5 | Varies | Up to 3 |
| Escrow payment protection | ✓ | ✗ | ✗ | ✗ | ✗ |
| No tradesperson subscription | ✓ | £50+/mo | ✓ | Credits | £15+/mo |
| Verified reviews (live) | ✓ | 5-day delay | ✓ | Mixed | ✓ |
| Background + qualification checks | ✓ | ✓ | Light | Basic ID | ✓ |
| Dispute resolution team | ✓ | ✗ | ✗ | ✗ | ✗ |
100%of TradeMatch payments held in escrow
Every loft conversion specialist job, every payment, every time. Funds held in a segregated client account until you sign off the work.
- Held in escrowFrom the moment the deposit clears until the job is signed off.
- Released on sign-offFunds release within 24 hours of you confirming the work is done to spec.
- Disputed = frozenIf something is wrong, the payment freezes pending review by our resolution team.
TradeMatch escrow operates through FCA-regulated payment providers. Customer funds are segregated from operating accounts and protected under UK consumer law.
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