Planning a loft conversion in 2025? You’re making a smart choice. House prices keep climbing. Mortgage rates have stabilised. Adding a loft conversion to your home beats moving. Loft conversions have become the smarter option for UK homeowners.
AC Design Solution are trusted loft conversion specialists. We’ve completed over 10,000 UK projects. We’ll show you exactly what your loft conversion will cost. We’ll explain what’s involved in a loft conversion process.
Your guide to loft conversion planning
Planning saves money on your loft or attic conversion. Most loft conversions can be carried under Permitted Development Rights. This means no planning permission if you follow the rules.
Every loft conversion must meet building regulations. Your new loft needs proper safety standards. It needs fire protection and loft insulation. Inspectors check your loft extension project regularly.
How much does a loft conversion cost in 2025?
The average cost of a loft conversion in 2025 is £45,000, marking a 7% increase from 2024. Loft conversion labour costs have risen 12%, though materials have stabilised. Different loft conversion types vary significantly in price:
| Type of conversion (30m²) | Average cost | Cost range |
|---|---|---|
| Velux/Rooflight conversion | £27,500 | £20,000-£35,000 |
| Dormer loft conversion | £45,000 | £35,000-£55,000 |
| Hip-to-gable loft conversion | £55,000 | £45,000-£65,000 |
| Mansard conversion | £70,000 | £55,000-£85,000 |
| Modular loft conversion | £40,000 | £30,000-£50,000 |
Costs vary based on property location, with London typically 30-40% higher. A loft conversion specialist will assess whether your loft is suitable for conversion during an initial consultation, checking head height, structural integrity, and access options.
We prepare clear planning, structural, and building regulation drawings for every loft type. Accurate plans that help you secure approvals and give your builder everything they need.
Learn more about loft conversion drawings →Loft conversion cost per m²
Cost per square metre depends on conversion type. A basic loft conversion costs £1,200-£1,800 per m². Complex ones reach £3,000 per m². The average cost of a dormer at 25m² is £42,000. That’s £1,680 per m².
Space in your loft affects pricing. Larger areas cost less per metre. A small loft conversion of 15m² costs more per metre than 40m².
Average Loft Conversion Cost UK 2025
Conversion costs in the UK vary by region. London leads the pricing table:
| Region | Average Cost | % vs National |
| London & South East | £58,000 | +29% |
| South West | £46,000 | +2% |
| East of England | £45,000 | 0% |
| West Midlands | £42,000 | -7% |
| North West | £40,000 | -11% |
| Yorkshire | £39,000 | -13% |
| North East | £37,000 | -18% |
| Scotland | £38,000 | -16% |
| Wales | £36,000 | -20% |
Loft Conversion Costs: London vs Rest of UK
London loft conversion costs can vary wildly from other regions. A specialist loft conversion company in London charges 30-40% more. Higher labour rates drive this. So do parking restrictions and logistics.
The cost of your loft conversion in London depends on zone. Central London costs most. Outer zones offer better value. Still, a loft conversion can add major value in London’s property market.
Loft Conversion Costs By Types – 2025 Estimate
Different types of loft conversions suit different needs. Here are several types of loft with costs:
Rooflight/Velux Conversion (£20,000-£35,000)
This is the cheapest way to convert a loft. This basic loft conversion uses existing roof space. No structural changes keep costs down. Takes 4-6 weeks. Perfect if you’re thinking about a loft conversion on a budget.
Dormer Loft Conversion (£35,000-£55,000)
The cost of a dormer loft includes extending from your roof. This creates headroom and adds 15-20m² of space. This conversion type suits most properties. The average cost of a dormer varies by size.
Hip to Gable Loft Conversion (£45,000-£65,000)
A hip-to-gable loft conversion involves changing your sloped roof to vertical. This conversion involves significant structural work. It maximises space in your loft though. Semi-detached houses love this option. Every loft square metre counts.
Mansard Loft Conversion (£55,000-£85,000)
A mansard loft conversion involves complete roof replacement. Creates maximum space with vertical walls. This conversion must have planning permission. Suits period properties. The complexity of the conversion justifies the cost.
Modular Loft Conversion (£30,000-£50,000)
A modular loft conversion involves pre-made sections. They’re built off-site. Installation takes just 2-3 weeks. Great when you need to convert a loft quickly.
Detailed Cost Breakdown for a Loft Conversion
Here’s what’s involved in a loft conversion cost breakdown:
| Element | Cost | % of Total | Details |
|---|---|---|---|
| Structural work | £12,000 | 27% | Beams, joists, dormers |
| Roof work | £8,000 | 18% | Tiles, weatherproofing |
| Windows | £4,500 | 10% | Glazing, installation |
| Stairs | £3,500 | 8% | Access to new loft |
| Insulation | £3,000 | 7% | Meet regulations |
| Electrical | £3,000 | 7% | Wiring, lighting |
| Labour | £8,000 | 18% | Skilled trades |
| Other | £3,000 | 5% | Contingency |
Every loft conversion must meet building control standards. We prepare full structural and building regulation drawings covering fire safety, structure, insulation and compliance with Approved Documents. Clear plans ready for approval and construction.
Building regulation drawings →Cost of Windows and Glazing
Windows have big impact on loft conversion costs. Velux windows cost £1,000-£1,500 each. Dormer windows cost £1,500-£2,500. Conservation areas need heritage glazing. This can add to the cost considerably.
Roofing Material
Material choice affects cost and planning. The cost can vary based on type:
- Concrete tiles: £35-£50/m²
- Clay tiles: £45-£70/m²
- Natural slate: £80-£120/m²
- Synthetic slate: £45-£65/m²
Your loft conversion company advises on local requirements.
Flooring
Your attic conversion needs acoustic-compliant flooring. Engineered wood costs £40-£80/m². Carpet costs £25-£60/m². Luxury vinyl costs £30-£70/m². Acoustic underlay adds £40-£60/m². It’s essential though.
Insulation
Proper loft insulation saves energy and money. January 2025 rules require 270mm in pitched roofs. Budget £2,500-£4,000 total. A loft conversion specialist ensures compliance.
Stairs
Your new loft needs safe access. Straight flights cost £2,000. Space-savers cost £3,500. Spirals cost £5,000. The loft conversion will depend on available space.
Surveys
Get these surveys before any loft conversion in the UK:
- Structural survey: £500-£800
- Party wall survey: £700-£1,500
- Asbestos survey: £200-£400
- Ecological survey: £300-£600
Building regulations
Every loft conversion must meet building standards. Local authority fees cost £1,200-£1,500. Private inspectors cost more but work faster. You need completion certificates to pay for your loft conversion through remortgaging.
Party wall matters
Party wall agreements are involved in a loft conversion for semis and terraces. Budget £1,700-£2,500 total. AC Design Solution has experience in loft conversions. We handle 500+ party wall agreements yearly.
Architectural Fees
A loft conversion specialist charges 10-15% of project value. Plans-only costs from £1,500. Full service reaches £7,500. Good design reduces the total cost of a loft through smart planning.
Other Costs To Consider
Several extras add to the cost:
- Scaffolding: £1,500-£3,000
- Skip hire: £600-£1,200
- Structural warranty: £800-£1,500
- Decoration: £1,500-£3,000
- Weather protection: £500-£1,500
Consider Project Managing Yourself
Managing your loft extension yourself saves 10-15%. You’ll coordinate trades directly. You’ll manage loft conversion labour costs yourself. Need 10-15 hours weekly though. Plus construction knowledge helps.
Take on DIY Tasks
DIY reduces the cost of your loft conversion:
- Decoration saves £1,500-£3,000
- Basic insulation saves £500-£800
- Carpentry saves £800-£1,200
- Flooring saves £600-£1,000
Never DIY structural or electrical work.
How much does an architect charge?
Architects charge 10-15% for loft conversion in 2025. RIBA architects cost £4,000-£8,000. Technologists cost £2,000-£4,500. The cost is directly linked to service level.
Hidden costs to consider
Unexpected issues impact on loft conversion costs:
- Asbestos removal: £2,000-£5,000
- Rotten timbers: £1,500-£3,000
- Foundation work: £3,000-£8,000
- Full rewire: £3,000-£5,000
- Chimney repairs: £1,000-£3,000
Budget 15-20% extra. Costs can vary unexpectedly.
Loft conversions often need new RSJs, altered load paths, and structural reinforcement. Our structural engineers provide calculations and guidance to make sure your loft is safe, compliant, and approved by building control.
Structural engineer →Project complexity
The complexity of the conversion affects price:- Listed buildings add 20-30%
- Conservation areas add 10-15%
- Unusual roofs add 15-25%
- Poor access adds 10-15%
- Winter work adds 5-10%
Age and condition of your property
Property age affects what’s involved in a loft conversion:- Victorian homes add £3,000-£7,000
- Edwardian homes add £2,000-£5,000
- 1950s-1960s add £3,000-£5,000
- 1970s-1980s add £1,000-£3,000
- 1990s+ add £500-£1,500
Legal costs and documentation
Legal requirements for loft conversion in the UK:- Planning application: £206-£462
- Building regulations: £1,050-£1,500
- Party wall agreements: £1,700-£2,500
- Structural warranty: £800-£1,500
Additional materials and features
Smart loft conversion ideas add value:- En-suite bathroom: £3,000-£8,000
- Walk-in wardrobe: £2,000-£4,000
- Air conditioning: £2,500-£4,000
- Built-in storage: £150-£300/m
- Extra skylights: £800-£1,500 each
Size of the loft
The total cost of a loft scales with size:- 15m² single room: £28,000
- 25m² with en-suite: £42,000
- 40m² two bedrooms: £60,000
- 50m² master suite: £72,000
How to find local experienced architects
Choose trusted loft conversion specialists carefully. Check RIBA and CIAT registers. Ask any loft conversion company about experience and insurance. AC Design Solution carries £2 million professional indemnity.5 Ways to Reduce Loft Conversion Costs
Your loft conversion will cost less if you:- Simplify design – saves £15,000
- Keep stairs put – saves £3,000-£5,000
- Book winter work – saves 10-15%
- DIY finishing – saves £2,000-£3,000
- Phase the work – spreads costs
Ecological surveys
Bat surveys are needed if signs suggest presence. Assessment costs £300-£500. If bats found, a gable loft conversion involves special measures. These cost £3,000-£10,000 extra.Loft conversion checklist
Before adding a loft conversion:- Check 2.2m head height
- Verify your loft is suitable for conversion
- Get structural survey
- Serve party wall notices
- Secure building regulations
- Arrange insurance
- Book inspections
FAQs
Do I need planning permission for a loft conversion?
Most attic conversions don’t need planning permission. They fall under Permitted Development Rights. You can proceed if staying within 50 cubic metres for houses. That’s 40 for terraced homes. Don’t extend beyond existing roof planes facing highways. Use materials matching your house. You’ll need permission for listed buildings though. Same for conservation areas and front dormers. Mansard conversions usually need permission too. Building regulations approval is always mandatory. This ensures structural safety and compliance.What is the cheapest way to do a loft conversion?
A basic loft conversion with rooflight windows is cheapest. Costs £20,000-£35,000 total. This conversion type works within existing roof space. No structural changes to the roof shape. Choose standard Velux windows to save money. Keep your chimney breast location for stairs. Do your own decoration. Winter scheduling brings 10-15% discounts. Lower contractor demand in winter. Self-project management saves another 15%. Need time and knowledge though.Can I do a loft conversion for 10K?
No. £10,000 won’t cover a legal loft conversion in 2025. Might cover basic floor strengthening. Maybe two Velux windows. But building regulations cost £1,200. Stairs cost £3,500. Electrics cost £3,000. Fire safety costs more. These exceed £10,000 before structural work. Before labour too. Minimum realistic budget is £20,000. That’s for the most basic loft conversion. Cheaper attempts risk safety issues. Legal problems when selling too.Can I reduce the cost of a loft conversion?
Yes. You can cut loft conversion costs by 15-30%. Winter projects cost 10-15% less. Lower demand in November-February. Managing yourself saves 15-20% on contractor margins. Need 10-15 hours weekly though. Standard designs beat bespoke ones. Simple rear dormer saves £15,000 versus L-shaped. Source materials directly for 20-30% savings. Check warranties stay valid. DIY decoration and flooring helps. The loft conversion can vary in cost based on your choices.Does a loft conversion add value to a house?
A loft conversion can add 15-20% to property value. Often exceeds the investment cost. £45,000 conversion on £300,000 property adds £45,000-£60,000. Immediate equity gain. Returns depend on local markets. Quality matters. So does space created. Bedroom plus bathroom generates best returns. Especially where larger properties are scarce. The benefits of a loft conversion go beyond money. Avoid £15,000 moving costs. Keep kids in schools. Create your perfect space.What’s the most expensive part of a loft conversion?
Structural work takes 25-30% of budget. Steel beams cost £2,000-£4,000. Floor joists cost £3,000-£5,000. Dormer construction costs £5,000-£15,000. Can’t compromise on safety. Building regulations demand compliance. Labour follows at 20-25% of budget. London day rates hit £450. Roofing adds 15-20%. This conversion involves significant engineering work. Structural elements need full investment. Safety and longevity matter most.How much is a loft conversion in London?
London costs 30-40% above national average. Rooflight conversions cost £28,000-£45,000. Rear dormers cost £45,000-£65,000. Hip to gable loft conversion costs £55,000-£75,000. Mansard costs £70,000-£100,000. Labour costs £350-£450 daily versus £250 nationally. Parking permits add £500-£1,500. Restricted working hours increase costs. Complex deliveries too. Central zones cost most. Outer zones still beat national average though.How do people afford loft conversions?
Most people (55%) remortgage to pay for your loft conversion. Access competitive rates at 2-3% above base. £45,000 over 20 years costs £250 monthly. About 25% use savings. They plan 2-3 years ahead. Home improvement loans cover 10% of conversions. Fixed rates without property security. Some phase work over 6-12 months. Complete structure first. Finish gradually. Planning ahead gives best rates.How long does a loft conversion take?
Timescales vary by conversion type. Rooflight takes 4-6 weeks. Dormer takes 6-8 weeks. Hip-to-gable needs 8-10 weeks. Mansard needs 10-12 weeks. A modular loft conversion involves 2-3 weeks on-site. Plus 4-6 weeks manufacturing beforehand. Add 2-4 weeks for planning. Building control approval takes time. Material ordering too. Weather impacts winter projects. Adds 20% to timescales. Weeks 2-4 are most disruptive.Can I live in my home during the conversion?
Yes. Most families stay home during their loft conversion. Expect disruption though. Daily noise 8am-6pm weekdays. Weeks 2-4 are loudest. Dust spreads despite protection. Need daily cleaning. Scaffolding for 8-12 weeks. Affects light and privacy. Workers need house access. Unless external access exists. Staircase installation blocks upper floors. Takes 2-3 days. Consider hotels during structural work. Especially with young children.What type of loft cannot be converted?
Some lofts won’t convert easily. Under 2.2m head height needs roof raising. Requires planning permission. Costs substantially more. Trussed rafter roofs need modifications. Costs £5,000-£10,000 extra. Still possible though. Shallow pitches under 30 degrees struggle for space in your loft. Some flat roofs lack capacity. Shared lofts in flats have restrictions. Always check if your loft is suitable for conversion. Get a structural survey first.
