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Convert your loft.

Dormer, hip-to-gable, Velux or full conversion — quoted from sketch or architect drawings.

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Hire a loft conversion specialist. Headroom checked, steels designed.

Read the brief on headroom, fire doors and Party Wall — then let Three local loft specialists quote.

Instant
01 · Ask

Rooflight, dormer or mansard?

Roof shape and headroom dictate options. Describe the loft and the AI tells you which conversion type fits.

Free
02 · Read the brief

Walk in informed

Building Regs Part B/K, Party Wall Awards, structural calcs, planning vs permitted development. Know the rules.

60 seconds
03 · Compare

Compare 3 specialist quotes

Three local specialists quote on the same drawing — structural, fit-out, en suite — so you compare like-for-like.

Ready when you are

Enter your postcode and get free quotes from local pros.

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Top tips

Hiring a loft conversions, without the regret.

Four moves that separate a smooth job from a nightmare.

Headroom is the deal-breaker.

Building Regs need 2.0m clear above stairs and over 50% of floor area. Survey headroom first — anything less and you're in dormer or roof-lift territory.

Fire-rated doors throughout the route.

Loft conversions need 30-minute fire-rated doors on every room off the stair from the ground floor up. Cheap doors fail Building Control.

Get a structural engineer.

Steel beams or padstones on existing walls need calcs. Pay £400–£800 for an SE — saves £5,000 in retrofit reinforcement.

Party wall agreement if attached.

Terraced or semi-detached needs a Party Wall Award before steel goes in. Skip this and your neighbour can stop the job.

Costs & timeline

Know what it costs. Know when it ends.

Indicative UK ranges and a typical week-by-week schedule.

Cost range

By job type

Inc. VAT · 2026
Source: NMT quotes
Rooflight only conversion (Velux)
£25k–£45k
Dormer loft conversionInc. en suite
£45k–£80k
Hip-to-gable conversion
£50k–£85k
Mansard conversion
£60k–£110k
Loft stair install only
£1.5k–£4.5k
Structural engineer fees
£400–£1.5k
!

Quote spread is typically ± 18% — always get 3 quotes.

Timeline

Dormer loft conversion · week by week

Typical
6 phases · 10 wk
W1
W2
W3
W4
W5
W6
W7
W8
W9
W10
Structural + design
Strip + steels in
Dormer build + roof
1st + 2nd fix
Plaster + finishes
Snags + handover
!

Schedule slips on dependencies — pad each phase by 10–20% for real-world delays.

At a glance

The full Loft Conversions briefing.

Visual breakdown of costs, timelines and the questions you should be asking.

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Video guide

Loft Conversions explained

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About

Loft Conversions services in the UK.

Everything you need to know before hiring a loft conversions.

A loft conversion is one of the most effective ways to increase your home’s square footage and market value without sacrificing garden space. By transforming an underutilised attic into a functional living area, you can create a master suite, a quiet home office, or an extra bedroom for a growing family.

Specialist loft conversion companies manage complex structural changes, from installing steel support beams to reconfiguring rooflines. They coordinate various trades, including carpenters, roofers, electricians, and plumbers, to ensure the new space is safe, insulated, and fully integrated with the rest of your home.

Whether you are looking for a simple rooflight conversion or a substantial mansard extension, hiring a dedicated specialist ensures the project meets strict UK Building Regulations. They navigate the technical challenges of head height, staircase placement, and fire safety to deliver a seamless addition to your property.

What to Expect When Hiring a Loft Conversion Specialist

  • Initial Feasibility Survey: A specialist will assess your roof pitch, head height, and floor joists to determine which conversion type suits your property.
  • Design and Planning: Most firms provide architectural drawings and structural calculations, ensuring the design complies with Permitted Development rights or requires a full Planning Application.
  • Structural Reinforcement: The existing ceiling joists are usually replaced with higher-grade timber or steel beams to support the weight of a new floor.
  • External Construction: For dormer or hip-to-gable projects, the roof is opened up, and the new structure is built and made watertight as quickly as possible.
  • First Fix Stage: Installation of internal stud walls, electrical wiring, plumbing for ensuites, and the new staircase.
  • Second Fix and Finishing: This includes plastering, fitting skirting boards, installing radiators, and final electrical connections before a final inspection.

Why Hire a Professional?

Loft conversions are major structural undertakings that should never be attempted as a DIY project. Professional installers understand the critical nature of load-bearing walls and the necessity of structural steel to prevent your roof from sagging or collapsing.

Compliance with UK Building Regulations is mandatory for any loft conversion. A professional ensures your project meets Part L (thermal efficiency), Part K (staircase safety), and Part B (fire safety), which includes installing fire-rated doors and mains-linked smoke alarms. Without a completion certificate from Building Control, you will struggle to sell your home in the future.

Specialists also carry the necessary Public Liability and Professional Indemnity insurance. This protects you against accidental damage to your property during the build and provides recourse if structural issues arise after the work is completed.

Typical Costs

Service Low £ High £ Notes
Velux (Rooflight) Conversion £25,000 £40,000 No change to roofline; requires 2.2m head height.
Dormer Loft Conversion £45,000 £65,000 Adds significant floor space and head height.
Hip-to-Gable Conversion £55,000 £75,000 Common for semi-detached/end-of-terrace homes.
Mansard Loft Conversion £65,000 £90,000+ Major aesthetic change; usually requires planning.
Architectural Plans & Calcs £1,500 £3,500 Essential for building regs and structural safety.

Prices vary significantly based on your location in the UK, the age of your property, and the level of internal finish. Adding an ensuite bathroom typically adds £5,000 to £8,000 to the total cost due to plumbing and tiling requirements.

How to Choose the Right Specialist

  • Check Accreditations: Look for members of the Federation of Master Builders (FMB) or the Guild of Master Craftsmen, which vet their members for quality.
  • Verify Experience: Ask to see a portfolio of similar conversions in your local area and, if possible, speak to previous clients about their experience.
  • Insurance & Warranties: Ensure they have valid insurance and offer an insurance-backed guarantee (usually 10 years) on the structural work.
  • Detailed Quotes: Avoid "ballpark" figures; ensure your quote is itemised, including skip hire, scaffolding, and VAT.

Questions to ask before hiring:

  • Will you handle the Building Regulations application and liaise with the inspector?
  • Is the staircase included in the quoted price, and will it meet the minimum 1.9m head height requirement?
  • How will you ensure the house remains watertight during the roof works?
  • What is the estimated timeline from the first day on-site to the final sign-off?

Frequently Asked Questions

Do I always need planning permission for a loft conversion?

In many cases, loft conversions fall under Permitted Development (PD), meaning you don't need full planning permission. However, specific limits apply to the volume of added space, and PD rights do not apply in Conservation Areas or to listed buildings.

How much value does a loft conversion add to a house?

According to Nationwide Building Society, a well-executed loft conversion that adds a bedroom and an ensuite can increase a property's value by up to 20%. It is widely considered one of the best home improvements for Return on Investment (ROI).

How long does a typical loft conversion take to build?

A simple Velux conversion can take 4 to 6 weeks. More complex dormer or hip-to-gable conversions typically take 8 to 12 weeks, depending on weather conditions and the complexity of the internal fit-out.

What is the minimum head height required?

For a loft to be legally habitable, you generally need a finished head height of 2.2 metres at the highest point. If your current attic is lower, you may need to lower the ceilings of the rooms below, which significantly increases costs.

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Expert guides

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