The short answer
Choose a company that provides a full written, itemised quote after a site visit, has verifiable references and completed projects, carries adequate insurance and will handle building regulations through an approved process. Avoid any company that presses for a deposit before design is agreed or discourages you from checking credentials. See get loft conversion quotes to compare specialists.
A loft conversion is one of the largest financial commitments most homeowners make. Choosing the wrong company can result in a substandard build, building regulations problems, a dispute over the contract or, in the worst cases, a contractor walking off site mid-project. The good news is that clear, verifiable signals separate reputable companies from risky ones — and most of them are available before you sign anything.
Choosing a loft company at a glance
- Site visit Essential before any quote
- Itemised quote Required — not a lump sum
- Insurance Check public liability and employer’s liability
- References Ask for completed projects you can visit or phone
- Contract Written contract before any deposit
- Building regs Confirm how they handle approval and inspections
The site visit is non-negotiable
No reputable company can quote accurately for a loft conversion without visiting the property and measuring the loft. A phone or online quote that does not involve a site visit is an estimate at best and a misleading number at worst — the builder who arrives on site will find the actual head height, roof structure and staircase constraints, which may differ materially from any assumptions made remotely. Refuse any quote that does not follow a proper site visit where the specialist measures the ridge height, assesses the roof structure and identifies the staircase position. A site survey is a basic professional standard; be cautious of any company that tries to skip it.
What the quote must contain
A credible quote should be written, itemised and comprehensive. It should clearly state what is and is not included. At minimum, confirm that the following are explicitly covered:
- Structural engineer’s design and fee
- Building regulations application fee and all inspection costs
- All structural work (joists, steels, roof alterations)
- Staircase supply and installation
- First-fix and second-fix electrics (lighting, sockets, mains smoke alarms)
- Insulation to the required U-value
- Plasterboard, skimming and basic plastering
- Windows and roof lights
- Fire doors on the escape route
- VAT clearly stated
Any of these absent from the quote should be queried explicitly. Plumbing for an en suite is often priced separately, which is reasonable; but it should be in writing and scoped clearly.
| Quote element | Should be included? |
|---|---|
| Structural engineer | Yes |
| Building regulations fees | Yes |
| Staircase | Yes |
| Electrics (first & second fix) | Yes |
| Fire doors | Yes |
| VAT stated clearly | Yes |
| Plumbing (en suite) | Often separate — get it scoped in writing |
Credentials and insurance to check
Ask every company you are considering for: their company registration number and check it on Companies House; public liability insurance (minimum £2 million is standard) and employer’s liability insurance; membership of a recognised trade body (LABC registered builder, or membership of the Federation of Master Builders or a similar body); and examples of recently completed loft conversions with references you can contact. Visit or phone at least two references before deciding. Be wary of companies that cannot provide references, whose online presence is thin, or whose registration details do not match what they have told you.
The contract
Before any work starts and before paying any deposit, you should have a written contract that clearly sets out: the agreed scope of work (referencing the itemised quote), the start and target completion dates, the payment schedule tied to milestones, the process for variations (any changes to the agreed scope must be agreed in writing), the contractor’s obligations to maintain insurance throughout, and the dispute resolution process. Verbal agreements are not adequate for a project of this scale. Trading Standards and Citizens Advice both advise consumers to insist on written contracts for building work. This page is general information and not legal or professional building advice. Always seek professional legal or building advice if you are in doubt about a company or a contract before signing or paying.
Compare loft conversion specialists for your project
Get quotes from assessed specialists who have been through a vetting process — compare itemised quotes, check references and make an informed decision before committing.
Frequently asked questions
How many quotes should I get for a loft conversion?
Get at least three written, itemised quotes from companies that have each carried out a site visit. This gives you enough information to compare prices, scope and approach, and to identify any quote that is significantly out of line.
Should I use a specialist loft conversion company or a general builder?
Either can do good work, but a specialist loft conversion company typically does more conversions per year, is more familiar with building regulations requirements, and may have established relationships with structural engineers and building control. Check credentials and references regardless of whether they specialise.
How much deposit should I pay for a loft conversion?
A deposit of 10–15% of the project value to secure the start date is reasonable. Be cautious of demands for a large deposit (30%+) before the build has started or before building regulations have been applied for. Structure payments against agreed milestones.
What should I do if my contractor goes off site mid-project?
Contact Citizens Advice and Trading Standards. If you paid by credit card, Section 75 of the Consumer Credit Act may give you recourse against the card provider. Review your contract for dispute resolution provisions. Do not pay a new contractor until you have confirmed the original contractor’s legal position. Take advice before proceeding.
Sources & further reading
- Trading Standards / Citizens Advice — guidance on building contracts, deposits and consumer rights
- Federation of Master Builders — guidance on choosing a builder and contract standards
- LABC (Local Authority Building Control) — registered builder schemes and building regulations obligations
- GOV.UK — Companies House for verifying contractor registration and financial standing
This is general information about loft conversions in the UK, not professional planning, structural, building or legal advice. Costs are typical illustrations, not quotes; timescales and outcomes vary with your property, location and chosen specialist. Always consult a qualified specialist and your local planning authority before starting work.