Loft Conversion Cost UK 2026: Full Pricing Guide for Contractors
How much does a loft conversion cost in the UK? Complete pricing breakdown for dormer, hip-to-gable, and Velux conversions — with regional variations and contractor tips.
How Much Does a Loft Conversion Cost in the UK?
A loft conversion typically costs between £25,000 and £75,000 in the UK, depending on the type of conversion, the size of the space, and where in the country the property is located.
| Conversion Type | Typical Cost Range |
|---|---|
| Velux / roof light | £15,000 – £25,000 |
| Dormer (standard) | £30,000 – £55,000 |
| Hip-to-gable | £35,000 – £55,000 |
| Mansard | £45,000 – £70,000 |
| L-shaped dormer | £50,000 – £75,000 |
These figures cover materials, labour, and standard finishes. They exclude VAT (20%) and any structural work below loft level.
What Affects the Cost of a Loft Conversion?
Floor area
The single biggest driver of cost. Most loft conversions create 20–50m² of usable floor space. Every additional 10m² typically adds £5,000–£10,000 to the total.
Conversion type
A simple Velux conversion (cutting holes for roof lights, laying a floor, adding a staircase) is fundamentally different to a full mansard, which rebuilds most of the roof structure. The type of conversion affects both materials and labour significantly.
Structural work
If steelwork is required — typically RSJ beams to support the floor or create a ridge opening — costs increase by £2,000–£8,000 depending on the number and size of beams.
Plumbing
Adding an en suite bathroom adds £4,500–£8,000 depending on specification. Running new hot and cold supplies up through the house adds cost on older properties.
Specification and finishes
Standard finishes (painted MDF, carpet, white sanitary ware) sit at the lower end. Premium finishes (hardwood flooring, tiled en suite, bespoke joinery) can add 20–35% to material costs.
Regional location
Material and labour costs vary significantly by region — see the breakdown below.
Regional Cost Comparison
| Region | Relative Cost vs National Average |
|---|---|
| London (inner) | +25–35% |
| London (outer) | +15–20% |
| South East | +10–15% |
| South West | 0–+5% |
| East of England | +5–10% |
| East Midlands | −5–0% |
| West Midlands | −5–0% |
| Yorkshire | −10–−5% |
| North West | −10–−5% |
| North East | −15–−10% |
| Scotland | −10–−5% |
| Wales | −10–−5% |
A dormer loft conversion costing £40,000 in the Midlands might cost £52,000–£54,000 in inner London.
Typical Cost Breakdown
For a standard dormer loft conversion (30–35m²) at national average rates:
| Trade / Cost Category | Typical Cost |
|---|---|
| Structural / carpentry (roof frame, floor joists, dormer structure) | £8,000–£14,000 |
| Roofing (felt, battens, tiles/slates, dormer cladding) | £3,500–£6,000 |
| Insulation (Kingspan/Celotex rafters + floor) | £2,500–£4,000 |
| Plasterboard and plastering | £2,000–£3,500 |
| Electrical (lighting, sockets, smoke detection) | £1,500–£3,000 |
| Staircase (supply and fit) | £2,000–£5,000 |
| Windows and Velux | £1,500–£3,000 |
| Decoration (first and second fix, painting) | £1,500–£2,500 |
| Scaffold (erect and dismantle) | £1,500–£2,500 |
| Skip hire and waste disposal | £400–£800 |
| Materials total (approx) | £12,000–£20,000 |
| Labour total (approx) | £14,000–£22,000 |
What’s Included and What Isn’t
Typically included:
- All structural carpentry (floor, roof frame, dormer)
- Roofing materials and installation
- Insulation to Building Regulations standard
- Plasterboard and skim plaster
- First and second fix electrics (no finishes)
- Staircase
- Windows
Typically excluded:
- Planning fees (if required — most loft conversions are permitted development)
- Party wall agreements
- Building regulations drawings and inspections
- En suite bathroom
- Fitted wardrobes or storage
- Floor finishes (carpet, wood flooring)
- Decoration and painting
- VAT (20%)
How to Price a Loft Conversion Accurately
Manual pricing of a loft conversion takes 3–5 hours of careful measurement, supplier lookups, and calculation. Prices from your price book are typically 2–6 weeks out of date by the time you send the quote.
PricingPro generates a fully itemised loft conversion estimate in minutes — pulling live prices from Jewson, Travis Perkins, Selco, and 100+ UK suppliers. Describe the job or upload your drawings, and the AI produces a line-by-line estimate you can review, adjust, and send straight to the client.
Generate a loft conversion estimate →
Frequently Asked Questions
Do I need planning permission for a loft conversion? Most loft conversions fall under permitted development rights and don’t require planning permission. Exceptions include properties in conservation areas, listed buildings, and certain types of conversion (mansard, for example, often requires consent). Always check with your local planning authority.
How long does a loft conversion take? A standard dormer conversion takes 6–10 weeks from start to handover. A Velux-only conversion can be completed in 3–4 weeks. Add time for planning permission if required.
What Building Regulations apply? All loft conversions require Building Regulations approval covering structural elements, fire safety, insulation, ventilation, and staircase design. Your local authority building control or an approved inspector will sign this off.
Can I do a loft conversion on a semi-detached house? Yes. Semi-detached properties are among the most common loft conversion candidates. If the party wall is affected, you’ll need to serve a party wall notice on your neighbour and potentially agree a party wall award.
Does a loft conversion add value? A well-executed loft conversion typically adds 15–25% to a property’s value — often significantly more than the cost of the conversion itself. It’s one of the best returns on investment in home improvement.
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