Before you sign with any builder, three checks take under an hour and cost nothing: the company record on GOV.UK, a written insurance certificate and a search of any trade body on its own website. GOV.UK says employers liability cover must be at least 5 million pounds, and Warwick District Council advises avoiding cash deposits and holding back the final payment until a completion certificate has been issued. This Rugby guide puts those checks in order, explains what each can and cannot prove, and shows which claims in the available checklists we could not source.
The short answer
Combine five checks, in writing
For a Rugby builder, check the legal name and address, read the free GOV.UK company record, ask for insurance certificates in writing, search any trade body on its own website and speak to recent references. Before the final payment, confirm a building control completion certificate has been issued. No single check proves a builder is legitimate, so keep every answer in writing.
Collect the legal name, address and company number first
Every other check depends on knowing exactly who you would be paying, so ask for the full legal name, registered address and company number in writing.
Checking a builder is legitimate is a short desk exercise, and it works best in a set order. Start with the name, because a trading name on a van or a website is not always the name of the business that signs your contract. Ask each builder who quotes for the legal name of the contracting party, the registered office or business address, and the company number if it is a limited company. A builder who is happy to work for you should be able to answer in one email.
Warwick District Council's guidance for homeowners suggests confirming that the company has a permanent base. It warns about firms that give only a phone number, especially a freephone number, because that does not show where they are. It also suggests asking how long the business has been operating.
The same council page advises against choosing the first trader who knocks at your door, and says that if you feel pressured to decide quickly you should look elsewhere.
Keep one note per builder with the name, address, company number and the date you checked each answer. If you want a wider view of how to build a shortlist first, our guide to finding a good builder in Rugby covers the questions to ask about past jobs and who will run the site.
Read the company record before you read the quote
GOV.UK lets you look up company details for free, including the registered address, the date of incorporation and the people listed as directors.
If the builder tells you they are a limited company, search for it on GOV.UK. The official page on getting information about a company says you can see the registered address and date of incorporation, current and resigned officers, filed document images, mortgage charge data, previous company names and insolvency information. It also says you can get some details for free and can sign up for free email alerts when a company updates its details.
Use the record to check the story against the facts. Does the registered name match the quotation exactly, and does the incorporation date fit what you were told about how long they have traded? A record confirms the party you would pay exists. It is not a verdict on quality.
Look at the officers and the history
The list of current and resigned officers shows who runs the company and who has left. If a builder has told you about a long family business and the record shows an incorporation date last year, ask about it politely. There may be a good reason, such as a new company set up for an established trade. A sensible builder will explain it plainly.
Insolvency information is on the same record. If it shows an issue, ask what happened before you rely on the quotation.
What if the builder is a sole trader?
A sole trader will not appear as a company, so there may be nothing to find on the company search. That does not make them illegitimate. It means more of the checking moves to the other items in this guide: a verifiable address, written insurance evidence, references you actually call and a clear contract. Ask for their full name and business address on the quotation.
Check the guidance: GOV.UK: get information about a company, Warwick District Council: how to find a reputable builder.
Ask for insurance in writing and know what the law requires
GOV.UK says employers must hold employers liability insurance of at least 5 million pounds, with a fine of 2,500 pounds for each day they are not properly insured.
Insurance is the check homeowners most often skip, and the one that matters most if something goes wrong on site. Warwick District Council advises making sure the company has insurance covering damage to your property and to your neighbours' property, and that either the contractor's or your own insurance covers death and personal injury. Ask each builder for the certificate and read it.
On employers liability, GOV.UK is specific. Anyone who becomes an employer must get employers liability insurance right away, from an authorised insurer, with cover of at least 5 million pounds. The fine for not having it is 2,500 pounds for each day the employer is not properly insured, and failing to show the certificate to an inspector when asked can bring a 1,000 pound fine. The certificate must be made available to employees, for example at the workplace or on a website. You do not need it if you employ only family members, or people based outside England, Scotland and Wales, so a small family firm may legitimately not hold it.
What the official page does not tell you is how to judge a public liability policy, so no figure for that is offered here. Book a Builder's checklist, published on 27 June 2026, suggests cover amounts without a source, so we have not repeated them. The practical test is simpler. Check that the certificate names the same company as your quotation and that the dates cover your build. If unsure, call the insurer on the certificate and ask them to confirm it.
Separately, tell your own home insurer about the building work before it starts. Our guide to home insurance during building work explains what to ask them and why the answer should be in writing.
Check the guidance: GOV.UK: employers liability insurance, Warwick District Council: how to find a reputable builder, Book a Builder: builder due diligence checklist.
Check trade bodies and registers at the source
A logo on a quotation proves nothing, so search the body's own website and note that Warwick District Council warns membership may have lapsed.
Trade body and scheme badges are useful signals, but only if they are real and current. Warwick District Council advises checking any trade association membership or Quality Mark Scheme approval with the relevant body, because membership may have lapsed, and asking about the builder's qualifications. A commercial checklist from BestBuilders, last updated on 13 August 2026, makes the same point in a sharper form: search the body's own website, not a logo.
It is worth knowing which schemes are legal requirements and which are voluntary. The same BestBuilders page says Gas Safe registration is required by law for gas work, describes NICEIC or NAPIT as effectively required for electrical work, and calls FMB, TrustMark and NFRC voluntary. It is a lead-generation site, so check the requirement for your own job with the body concerned.
TrustMark describes itself as the Government Endorsed Quality Scheme for work homeowners have done in or around their home, and says a registered business has been thoroughly vetted. Its find a tradesperson tool searches by what you need and where you are. The page does not explain how the endorsement works in practice, so use it as one check among several.
The table summarises what each check can and cannot tell you.
| Check | Where to do it | What it shows | What it does not show |
|---|---|---|---|
| Company record | GOV.UK company search | Registered address, incorporation date, officers, previous names, charges, insolvency information | Insurance cover or the quality of past work |
| Insurance certificate | Ask the builder; confirm with the insurer | Cover held, dates and named company | Whether the policy suits your job unless you read it |
| TrustMark | TrustMark find a tradesperson tool | Whether a business appears as a registered business | How the endorsement works in practice |
| Gas Safe or electrical scheme | The register for that trade | Registration for the specific trade | Anything about general building work |
Check the guidance: Warwick District Council: how to find a reputable builder, TrustMark: find a tradesperson, BestBuilders: how to check builders are registered.
Test the paper trail before any money moves
Warwick District Council advises getting every estimate in writing, avoiding cash deposits and tying staged payments to the amount of work completed.
A legitimate builder leaves a paper trail, and so should you. Warwick District Council advises getting all estimates in writing, with an outline of the work, start and completion dates, security and safety, waste disposal and working hours. Its page suggests getting written quotes from at least three reputable companies, and notes that for larger jobs an industry-wide contract such as JCT is available. Our quote checklist covers the scope lines.
On payment, the council advises avoiding cash deposits, which it says are usually unnecessary, and avoiding cash in hand payments, because without paper records you may be unable to prove payments were made if problems arise. For all but small jobs it says payments may be staged and should reflect the amount of work completed. We have not quoted a deposit percentage: the council and BestBuilders pages set none, and Book a Builder's has no source. Ask each builder to state what they want and why. Our stage payments guide shows how to link payments to evidence.
Ask for references you can actually call
Warwick District Council advises asking for references and examples of recent work, and checking that the builder has done similar work, since a specialist in small extensions may not handle a loft conversion. BestBuilders suggests speaking to two or three recent customers, ideally for a similar job, and checking more than one review platform, favouring detailed recent reviews. Phone the reference and ask whether the work finished close to the price and the programme.
Photograph progress and keep the invoices
The council also suggests photographing the work as it progresses to create a record. Pair that with dated invoices and a bank transfer trail, so a clear record exists if you ever need to dispute something.
Check the guidance: Warwick District Council: how to find a reputable builder, BestBuilders: how to check builders are registered.
Keep checking until the completion certificate is in your hands
Warwick District Council advises confirming that the work meets Building Control requirements and that a completion certificate has been issued before making the final payment.
Legitimacy is not only a pre-contract question. The council's advice is to make sure your builder calls out the building inspector at all relevant stages, if they have agreed to do so for you, and to confirm before final payment that the work meets building control requirements and that a completion certificate has been issued. Planning permission and building regulations are separate checks, so ask which applies to your job.
In Rugby, building control is run by Warwick Building Control, a partnership of Rugby Borough Council and Warwick District Council. Rugby Borough Council's page says it handles building regulations, demolitions and dangerous structures. Ask each builder who will make the application, who will arrange the inspections and who will give you the certificate at the end. A vague answer deserves a second opinion from the council.
Hold back the final payment until the certificate and any guarantee or compliance paperwork is in your hands. If you are planning an extension, our guide to extension building regulations explains what inspectors check and when.
Check the guidance: Warwick District Council: how to find a reputable builder, Rugby Borough Council: Warwick Building Control.
A short checklist to run on every builder, including us
The checks above take under an hour per builder and cost nothing, so apply them to everyone who quotes, including Belmax.
Get the legal name, address and company number. Read the company record. Request the insurance certificate and check the dates and company name. Search each trade body or scheme on its own website. Ask for two or three recent references and ring them. Compare written quotations for scope, payments and dates. Agree who deals with building control, and hold back the final payment until the completion certificate is issued.
You are welcome to put Belmax Builders Limited through the same checks as anyone else. This guide gives general advice from the sources listed and does not describe any Belmax registration, insurance or membership, so ask us for documents as you would any firm. If you would like to send a brief for a quotation, include your postcode, photographs, any drawings and the rooms involved, so the conversation can start with specifics.
Check the guidance: Warwick District Council: how to find a reputable builder.
What clients say
Recent words from Belmax clients.
Three public five-star review excerpts, checked 24 September 2026.
“We have been really happy with the service from Belmax Builders. They are reliable, professional and, most importantly, always kept to the agreed schedule.”
“Belmax did the job to very high standard, communicated with us the whole time and explained really well what to expect.”
“Job was started on time and Rob kept us up to date every step of the way. The finished conversion looks amazing.”
Frequently asked questions
How do I check a builder is legitimate in Rugby?
Start with the legal name, address and company number, then read the company record on GOV.UK, ask for insurance certificates, check any trade body on its own website and speak to recent references. Rugby building control is run by Warwick Building Control, so ask who will arrange inspections and the completion certificate. No single check is enough, so combine them and keep your answers in writing.
Can I check a builder on Companies House for free?
Yes. GOV.UK says you can get some details about a company for free, including the registered address, date of incorporation, current and resigned officers, previous names, mortgage charge data and insolvency information. A sole trader will not appear as a company, so ask them for a full name and a traceable business address instead. A record confirms the business exists. It does not measure the quality of its work.
Does a builder need insurance?
GOV.UK says anyone who becomes an employer must have employers liability insurance of at least 5 million pounds, with a 2,500 pound daily fine if not properly insured. Employing only family members is exempt. Warwick District Council also advises cover for damage to your property and your neighbours' property. Ask for the certificate, check the dates and company name, and confirm it with the insurer if unsure.
Should I pay a deposit to a builder before work starts?
Warwick District Council advises avoiding cash deposits, which it says are usually unnecessary, and avoiding cash in hand payments because you may be unable to prove them later. For all but small jobs it says payments may be staged to reflect work completed. No official figure is set in the sources we opened, so ask the builder to explain any deposit in writing before you agree.
What should I check before making the final payment?
Warwick District Council advises confirming that the work meets Building Control requirements and that a completion certificate has been issued before the final payment. In Rugby, building control is run by Warwick Building Control. Ask who made the application, who arranged the inspections and where your certificate is. Keep your photographs, invoices and payment records with it, so you hold a complete record of the job.
Sources
Figures, fees and rules change. Every source below was checked on 4 November 2026.
- GOV.UK: get information about a companyFree company details: registered address, incorporation date, officers, previous names, charges and insolvency information.
- GOV.UK: employers liability insuranceEmployers must hold at least 5 million pounds of cover; fines of 2,500 pounds a day without it; family-only exemption.
- Warwick District Council: how to find a reputable builderCouncil advice on quotes, insurance, trade body checks, deposits and a completion certificate before final payment. Page carries no date.
- TrustMark: find a tradespersonDescribes itself as the Government Endorsed Quality Scheme; registered businesses are described as vetted.
- BestBuilders: how to check builders are registeredCommercial lead site, updated 13 August 2026: six-point checklist, search a body's own site not a logo; no deposit threshold given.
- Book a Builder: builder due diligence checklistCommercial lead site, published 27 June 2026: 12-point checklist; most figures unsourced so none are used here.
- Rugby Borough Council: Warwick Building ControlBuilding control in Rugby is run by Warwick Building Control, a partnership of Rugby Borough Council and Warwick District Council.