How to Vet a Builder: A Step-by-Step Guide
A practical method for checking a builder before you hire them, scaled to the size of your job.
The method
Vetting a builder is a process, not a single check. Done in the right order, it takes a few evenings at most.
To vet a builder, you confirm who the business is, see its insurance in writing, test its reputation through reviews and references, look at finished work, and judge how it behaves at the site visit and in its quote. Each check answers a different question, and together they give you a fair picture before you commit.
The order matters. The quick desk checks come first because they rule people out cheaply. The slower checks, ringing references and visiting past jobs, are saved for the two or three builders you are seriously considering. This guide sets out that method, step by step, with notes on what a good answer looks like and when to dig further.
For an overview of every check and where to do it, see our guide to choosing and checking a building contractor.
Step by step
The vetting process, in order
Steps one to four can be done from your kitchen table. Steps five to eight are for your shortlist.
Write down what you need
A short description of the job, roughly when you want it done and anything that matters to you, such as access, working hours or pets. Giving every builder the same description is what makes their answers and quotes comparable later.
Collect the basic details
For each name: the full business name, whether it is a limited company or a sole trader, a trading address, a phone number and an email. A business that is reluctant to give you an address is worth setting aside at this stage.
Check the business record
For a limited company, search the free Companies House register. Check the company is active, that its name and number match the paperwork, and that its accounts and confirmation statement are not overdue. Checking a company on Companies House explains each part of the record.
Scan the reviews
Look at two or three platforms, not one. Read the most recent reviews first, then the critical ones, and see how the business replied. You are looking for a consistent pattern, not a perfect score. How to read builder reviews has more on spotting what matters.
Ask for the insurance
Request the certificate or policy schedule. Check the insured name matches the business, the dates cover your job, and the activities listed include the work you want done. Checking a builder's insurance explains how to read it.
Speak to references
Ask for two or three recent customers with similar jobs, and ring them rather than relying on a written note. Taking up references suggests the questions to ask.
See finished work
Photos help, but a real job is better, ideally one completed a while ago so you can see how it has lasted. Even a look from the street tells you something.
Judge the visit and the quote
Did they turn up when agreed, look at the job properly, and send a clear written quotation when they said they would? How a builder runs the quoting stage is a fair preview of how they will run the job.
What good looks like
What a good answer looks like at each stage
You are not looking for perfection. You are looking for consistency: the details line up and the builder is open with you.
The details match
The name on the quote, the insurance certificate, the company record and any VAT number all point to the same business. Small differences, such as a trading name, should have a simple explanation.
Documents arrive easily
Insurance paperwork and references are provided promptly, without excuses. Good builders are asked for them often and tend to have them ready.
Reviews tell a steady story
Recent reviews look like older ones, complaints are answered calmly, and problems appear to have been put right.
References are specific
Past customers describe the job, the timing and how issues were handled in their own words. Vague praise is less useful than specifics.
Timings are kept
The visit happens when agreed and the quote arrives roughly when promised, or the builder lets you know why it hasn't.
The quote is complete
The scope, price, payment terms and warranty are written down, and extras such as scaffolding or waste removal are either included or clearly excluded.
Proportion
How much checking your job needs
The checks scale with the job. For a small repair from a builder you already know, confirming the insurance and getting the price in writing may be enough. For a larger project, such as a roof replacement or an extension, every step is worth doing, because more money is involved, the work lasts longer and more can change along the way.
A useful rule is to match your effort to what you would lose if the job went badly. A modest repair can be put right quickly. A large project that stalls halfway is far harder to recover, which is why references, previous work and the written terms matter most on bigger jobs.
Deciding how many builders to vet follows the same logic. Two for a small job, three for a larger one, is usually enough to compare prices and approaches without doubling the work. How many quotes to get covers this in more depth.
Two kinds of check
What you can check yourself, and what you have to ask
Some checks rely on public records. Others rely on the builder. The strongest picture comes from both.
You can check independently
- A limited company's record on Companies House
- A VAT number, using the checker on GOV.UK
- Scheme membership, on the scheme's own register
- That an insurer is authorised, on the FCA register
- Reviews across several platforms
- Finished work you can see from the street
You have to ask the builder for
- Their insurance certificate or schedule
- Contact details for recent customers
- Photos or addresses of previous jobs
- Who will actually carry out the work
- Their workmanship warranty terms
- A written quotation and payment terms
When something doesn't add up
Asking the follow-up question
Most gaps have an innocent explanation. A company may trade under a different name from its registered one. A new business may have few reviews. A builder may be between insurance renewals and waiting for the new certificate. The right response is usually a polite question, not an immediate no.
What matters is the answer. A clear explanation, backed by a document where one exists, is reassuring. Evasion, or pressure to skip a check and sign today, is a reason to move on. Red flags when hiring a builder sets out the signs worth weighing, and what are the warning signs of a bad builder? gives the short version.
Keep brief notes as you go: who you spoke to, what they said and which documents you saw. It makes comparing builders easier, and it gives you a record if a question comes up later.
Before the visit
Five questions for the first phone call
A short call before anyone visits saves time on both sides. The answers also tell you a good deal about how the business is run.
Is this the kind of work you do regularly?
A builder who does your type of job week in, week out will price it more reliably and spot problems sooner. Ask roughly how many similar jobs they have done recently.
Do you cover my area?
Distance affects price, response times and how easily the builder can come back to put something right. A builder working well outside their normal patch may be less available later.
When could you realistically start?
A good builder is often booked ahead. An honest answer of several weeks is more reassuring than a promise to start tomorrow on a large job.
Can you send your insurance details and a couple of references?
Asking early means you can check them before the visit rather than after the quote, when it is easier to feel committed.
How will the quote reach me?
You are looking for a written quotation, by email or on paper, within a timescale they are willing to name. Ask what it will include.
Familiar faces
Vetting a builder you already know
It can feel awkward to ask a builder you have used before, or one a neighbour swears by, for insurance and references. It helps to treat the checks as routine rather than personal. You are not questioning their honesty. You are making sure the paperwork for this job is in order, which protects them as much as you.
The checks can be lighter. You already know how they communicate and whether they turn up. What changes from job to job is the scope, the price and the paperwork, so focus there: a current insurance certificate that covers the work, a written quote for this job, and clear payment and warranty terms.
The same applies if the job is bigger than anything they have done for you before. A builder who handled a small repair beautifully may not be set up for a larger project with other trades involved. Ask how they would run it and who would do which parts.
Working through the same list for every builder keeps the comparison fair and stops a friendly visit from skipping a step. Our contractor checking checklist sets every check out in order, ready to use.
Where Mortaro fits
Part of the vetting done before you meet anyone
If you use Mortaro, we appoint a contractor from our network for your job. Every contractor in the network was checked before being introduced to any customer: public liability insurance, reviews and references, the warranties they provide, trade experience and prior work history, and their ability to meet our standards.
Your contractor carries out the work and is named in your written quotation before you commit, so you are free to run any of the checks above as well. Our contractor network explains what we check, and what does vetted contractor mean? explains why it is worth asking any service exactly which checks sit behind the word.
Straight answers
Questions about vetting a builder
How long does it take to vet a builder?
The desk checks take minutes per builder. Speaking to references and seeing previous work takes longer, so most people save those for their final two or three. On a larger job, allow a few evenings in total.
What if a builder has no reviews?
It may simply be a newer business, or one that works mostly through recommendations. Lean more heavily on references, previous work and the written paperwork, and ask the builder why reviews are thin.
Do I need to vet a builder a friend recommended?
It is still worth confirming the insurance and getting the quote in writing. Your friend's experience is a strong reference, but their job may have been different in size or type from yours.
Is being in a trade scheme enough on its own?
It is a useful sign, but schemes check different things. Confirm membership on the scheme's own register and still run the other checks. Trade accreditation schemes explained covers what the main ones involve.
What if a builder refuses to show me their insurance?
Ask why. There may be a simple reason, such as a renewal in progress, in which case a date for the new certificate is a fair answer. An outright refusal, with no explanation, is a reasonable point at which to move on to another builder.
Start here
Tell us about the work you have in mind
We will confirm we cover your postcode, arrange a site visit with a contractor from our network and send you a written quotation. No charge, no obligation.