How Much Does a Loft Conversion Cost in the UK? (2026 Price Guide)

How Much Does a Loft Conversion Cost in the UK?

Loft conversions are one of the most popular ways to add extra bedrooms or office space without extending the footprint of a property.

Typical UK loft conversion costs:

• Basic rooflight (Velux) loft conversion: £25,000 – £40,000
• Dormer loft conversion: £35,000 – £60,000
• Hip-to-gable conversion: £45,000 – £75,000
• Mansard loft conversion: £60,000 – £100,000+

Average cost per m²:

• £1,500 – £3,000 per m² installed

Final cost depends heavily on roof structure, access, stair installation, and dormer complexity.

Loft Conversion Cost Per m² (UK Breakdown)

Typical installed costs per m²:

• Basic Velux conversion: £1,500 – £2,000 per m²
• Dormer conversion: £2,000 – £2,600 per m²
• Structural / hip-to-gable: £2,400 – £3,000 per m²
• Mansard conversion: £2,800 – £3,500+ per m²

Types of Loft Conversions

Velux (Rooflight) Conversion

• Most cost-effective option
• No major roof structure changes
• Uses existing roof space
• Best for adequate head height lofts

Typical cost: £25,000 – £40,000

Dormer Loft Conversion

• Most common type in the UK
• Extends roof vertically to create more headroom
• Suitable for bedrooms and bathrooms

Typical cost: £35,000 – £60,000

Hip-to-Gable Conversion

• Used for semi-detached and detached homes
• Replaces sloping roof with vertical wall
• Creates significantly more usable space

Typical cost: £45,000 – £75,000

Mansard Loft Conversion

• Most complex and expensive option
• Often used in terraced homes
• Requires major roof restructuring

Typical cost: £60,000 – £100,000+

What Affects the Cost of a Loft Conversion?

1. Roof Structure and Height

• Adequate head height reduces structural costs
• Low roofs require structural modifications or lowering ceilings
• Complex roof shapes increase engineering costs

2. Staircase Installation

A staircase is one of the biggest hidden costs:

• Standard staircase: £2,000 – £5,000
• Custom staircase: £5,000 – £10,000+
• Structural changes for stairs: £1,000 – £5,000

3. Structural Steelwork

Most loft conversions require steel reinforcement:

• RSJs and supports: £2,000 – £8,000+
• Complex structural redesign: £5,000 – £15,000

4. Dormers and Extensions

Adding dormers significantly increases cost:

• Small dormer: £10,000 – £20,000
• Large dormer: £20,000 – £35,000+

5. Plumbing and Bathrooms

If adding an en-suite:

• Bathroom installation: £3,000 – £10,000
• Plumbing runs to loft: £1,000 – £5,000
• Soil stack extensions: £1,000 – £3,000

Labour Costs for Loft Conversions

Labour typically accounts for 40%–60% of total cost.

Typical daily rates:

• Builder: £180 – £300 per day
• Roofer: £200 – £350 per day
• Carpenter: £200 – £350 per day
• Electrician: £200 – £400 per day
• Plumber: £200 – £400 per day

Typical build duration:

• Velux conversion: 2–4 weeks
• Dormer conversion: 4–8 weeks
• Mansard / structural conversion: 8–12+ weeks

Example Loft Conversion Costs

Velux Loft Conversion (Basic)

• Structural works: £10,000 – £15,000
• Finishes and insulation: £10,000 – £20,000
• Staircase: £3,000 – £6,000
• Total cost: £25,000 – £40,000

Dormer Loft Conversion (Standard)

• Dormer construction: £15,000 – £25,000
• Internal works: £15,000 – £25,000
• Staircase and steelwork: £5,000 – £10,000
• Total cost: £35,000 – £60,000

Mansard Loft Conversion (High-End)

• Structural rebuild: £25,000 – £50,000
• Internal finishes: £20,000 – £30,000
• Plumbing/electrics: £10,000 – £20,000
• Total cost: £60,000 – £100,000+

Hidden Costs in Loft Conversions

Common additional costs include:

• Planning permission (if required): £500 – £2,000
• Building regulations approval: £1,000 – £3,000
• Structural engineer fees: £500 – £2,000
• Party wall agreements: £700 – £2,000
• Roof strengthening: £2,000 – £10,000+
• Waste removal: £200 – £800
• Scaffolding: £1,000 – £4,000

Regional Price Differences in the UK

• London & South East: 10%–30% higher
• Midlands: average UK pricing
• North of England: slightly lower labour costs
• Rural areas: higher due to access and logistics

How Long Does a Loft Conversion Take?

• Velux conversion: 2–4 weeks
• Dormer conversion: 4–8 weeks
• Hip-to-gable: 6–10 weeks
• Mansard conversion: 8–12+ weeks

Delays are often caused by weather, structural issues, or material lead times.

How to Get an Accurate Loft Conversion Quote

To avoid inaccurate pricing, contractors should:

• Check roof height and structure properly
• Include steelwork allowances upfront
• Assess staircase positioning early
• Confirm bathroom/plumbing requirements
• Include scaffolding and access costs
• Price insulation and fire safety compliance correctly
• Allow contingency for structural surprises

Loft conversions are frequently underquoted due to hidden structural complexity.

How Pricing Penguin Helps Contractors

Customers often don’t have a clear understanding of what a construction job should cost before they speak to a tradesperson. As a result, many enquiries come in “cold” — with unrealistic expectations, mismatched budgets, or purely price-driven intent. This leads to wasted time quoting jobs that were never viable in the first place.

Pricing Penguin changes that dynamic by giving customers a realistic, data-driven price range before they ever pick up the phone or submit an enquiry.

Instead of guessing or waiting for a contractor to explain costs after the fact, customers can immediately understand:

• What their type of job typically costs in their area
• What drives the price up or down (size, materials, complexity, access, etc.)
• Whether their budget is realistically aligned with the work they want done

This creates a pre-qualified customer before the first interaction even happens.

For contractors, this means fewer wasted site visits, fewer unrealistic enquiries, and a much higher proportion of leads that are actually ready to proceed. Rather than spending time filtering out low-quality leads, tradespeople can focus on quoting and winning work that already fits their pricing structure.

In short, Pricing Penguin acts as a pricing filter between customer expectation and real-world construction costs — improving conversion quality, saving time, and helping contractors focus on profitable work instead of time-wasting enquiries.

FAQ

How much does a loft conversion cost in the UK?

Typically £25,000 – £60,000 depending on type and complexity.

What is the cheapest loft conversion?

A Velux (rooflight) conversion.

Does a loft conversion add value?

Yes — often adding a bedroom significantly increases property value.

Do you need planning permission for a loft conversion?

Often not for Velux or small dormers, but mansard conversions usually require it.

Conclusion

Loft conversions in the UK typically cost between £1,500 and £3,000 per m² depending on structural complexity and type.

Velux conversions are the cheapest, dormers are the most common, and mansard conversions are the most expensive.

For homeowners, understanding cost drivers prevents unexpected budget overruns.

For contractors, accurate estimating is essential to protect margin and win consistent work.

Better pricing leads to better projects — and stronger construction businesses.