Loft Conversion Cost Guide
Loft conversion costs in the UK usually start at around GBP 22,500 for a simple shell or rooflight project and can rise to GBP 80,000 or more for larger or more complex conversions. This guide covers realistic 2026 price ranges, common conversion types, labour costs, major extras, and what to check before hiring a loft specialist.
Get free quotes from local tradespeople
Enter your postcode to see who's available in your area
Quick Cost Summary
Prices are indicative and vary by location, property type, and specification. Always get at least three quotes.
Types of Loft Conversion
Velux or Rooflight Conversion
This is usually the cheapest loft conversion route because it keeps the main roof shape intact and focuses on windows, insulation, and internal fit-out.
Pros
- Usually the most affordable option
- Less structural work than other conversion types
- Can be quicker to complete
Cons
- Adds less usable headroom than some alternatives
- Not every loft is suitable
Best for: Homes with enough existing loft height and a simpler conversion plan
Dormer Loft Conversion
Dormers extend out from the roof to create more usable floor area and headroom. They are one of the most common conversion choices.
Pros
- Creates much more practical internal space
- Very common on many UK homes
- Can work well for extra bedrooms and ensuites
Cons
- More expensive than a rooflight conversion
- Involves more structural alteration
Best for: Homeowners who need meaningful extra space rather than just a basic loft room
Hip-to-Gable or Mansard Conversion
These are more structural and often more expensive conversion styles, but they can unlock far more usable space in the right property.
Pros
- Can maximise usable loft area
- Often the best route for larger rooms
- Can deliver the strongest space gain
Cons
- Higher cost and greater build complexity
- Usually more design and approval work
Best for: Larger loft projects where space gain is the priority and the budget can support it
The type of conversion has the biggest effect on cost, with rooflight projects usually costing the least and major structural conversions costing much more.
What Affects the Cost
- Type of loft conversion being built
- Size of the loft and existing roof structure
- Need for steelwork, staircase, and structural alterations
- Whether bathrooms, dormers, or bespoke joinery are included
- Planning, design, and building control requirements
- Regional labour costs and site access
Labour Cost Breakdown
Labour is typically 30–50% of the total installation cost. The complexity of the job determines how long it takes.
What Is Usually Included
- Structural building work for the loft shell
- Insulation and standard internal build-up
- Basic staircase installation
- Roof windows or dormer work depending on the design
- Core conversion labour and site management
Extra Costs to Expect
These aren't always required, but it's worth knowing about them before you get quotes.
Running Costs & Potential Savings
A loft conversion does not normally reduce bills directly, but it can add valuable usable space and improve the overall value and flexibility of the home. Energy performance also depends on the insulation standard and how well the new room is detailed.
Ready to get quotes?
Compare free, no-obligation quotes from trusted local tradespeople. No sign-up needed.
Get Free QuotesWhat to Check Before Hiring
Use this checklist when getting quotes to make sure you're hiring the right person at the right price.
- Ask exactly which conversion type is being priced
- Check whether design, calculations, and approvals are included
- Confirm whether the quote includes staircase and structural steelwork
- Ask what finishing work is excluded from the contract
- Check whether bathrooms, wardrobes, or decoration are extra
- Make sure the programme and payment stages are clearly set out
Frequently Asked Questions
How much does a loft conversion cost in the UK?
Costs vary widely, but simple loft conversions can start in the low tens of thousands while large structural projects can go far higher.
What is the cheapest type of loft conversion?
A rooflight or Velux-style conversion is usually the cheapest because it generally involves less structural change than dormer or mansard options.
Why do dormer loft conversions cost more?
Dormers usually involve more structural work, more external build work, and more detailed weatherproofing than simpler rooflight conversions.
How long does a loft conversion take?
Smaller projects can be completed in several weeks, while larger conversions often run for two to three months or more.
Are design fees included in loft conversion quotes?
Not always. Some specialists include parts of the design process, while others price drawings, engineering, and approvals separately.
What usually increases the final cost?
Bathrooms, bespoke storage, structural surprises, higher-end finishes, and more complex roof alterations are the main reasons loft conversion budgets grow.
Get free quotes from local tradespeople
Enter your postcode — we'll match you with available tradespeople in your area