Begin With a Clear Brief

The quality of the quotes you receive depends almost entirely on the quality of the information you hand over. Before you contact anyone, write a short but specific brief covering the scope of work, approximate dimensions, the materials and finishes you have in mind, and the timescales you are working towards. Note whether planning permission or building regulations approval is required, whether a party wall agreement is needed, and how the builder will access the site — parking, skip permits and welfare facilities all add cost if they are not discussed upfront.

It also helps to say whether you intend to live in the property during the works. A family staying put through a kitchen refit changes the pace of the job and the builder's programme. Being honest about your budget range, rather than keeping it secret, will save you weeks of quotes that were never going to work.

Check Credentials, Insurance and Accreditations

Any competent builder should be able to produce paperwork without hesitation. Ask for, and actually read, the following:

• Public liability insurance — typically at least £2 million of cover, protecting your property if something is damaged.
• Employer's liability insurance — legally required if they employ anyone, with a minimum of £5 million. Ask to see the current certificate, not last year's.
• Registration for specialist trades — gas work must be carried out by someone on the official gas safety register, and electrical work should be certified by a registered electrician.
• Company details — a registered business address, a company number if they trade as a limited company, and a VAT number if their turnover requires it.
• Membership of a reputable trade body or government-endorsed quality scheme — these usually require proof of insurance, a trading history and independent inspection of completed work.

Be wary of a builder who only has a mobile number and no fixed address. It is not automatically a red flag, but it makes it far harder to pursue a problem later.

Follow Up References Properly

A list of names proves nothing on its own. Ask for three recent customers, and try to include one job finished within the last six months and one completed two or three years ago. The recent one tells you how they work day to day; the older one tells you whether problems were resolved after the final invoice was paid.

Ask specific questions rather than "were they any good". Did the final bill match the quote? How were variations priced? Did they turn up when they said they would? How did they handle a mistake? Would you use them again? If possible, ask to visit a current site — most builders will happily agree, and it tells you a great deal about how tidy and organised they are.

Online reviews are useful, but read for patterns rather than isolated complaints. A single poor review about a delayed delivery is very different from repeated mentions of unanswered phone calls.

Insist on a Detailed Written Quote

Verbal estimates are worthless. You want a written quote, and you should understand the difference between a quote, which is a fixed price, and an estimate, which is an educated guess. A good quote itemises labour, materials, preliminaries such as scaffolding and waste removal, and VAT. It also states clearly what is excluded — decoration, making good, replacing damaged plasterboard, or relocating services are common omissions.

Check that the quote covers the certification you will need: building regulations sign-off, electrical installation certificates, gas safety documentation and any warranty for windows or specialist installations. Confirm the start date, the expected completion date, and who is responsible for obtaining approvals. If more than one page of specification is missing, ask for it in writing before you sign anything.

Agree a Sensible Payment Schedule

How a builder asks to be paid tells you a lot about their business. As a rule:

• Never pay more than a modest deposit upfront — 5 to 10 per cent, or the cost of materials genuinely ordered for your job.
• Structure payments against milestones, such as first fix, plastering, second fix and completion, and make sure each payment lags behind work already completed.
• Avoid paying in cash, and always pay the business, not a personal name, so you have a clear paper trail.
• Hold back a retention of 2.5 to 5 per cent for a few weeks after completion, to cover snagging and any defects that appear once the heating is on.
• Do not release the final payment until you have the certificates, warranties and a completed snagging list.

If you are asked to fund a builder's cashflow for a job that has barely started, walk away.

Put It in Writing — and Watch for Warning Signs

Even a straightforward renovation deserves a written contract setting out the scope, price, payment schedule, timescales, insurance details, and how variations and disputes will be handled. Agree in writing, before work begins, that any change to the specification will be priced and approved in writing. Keep a simple daily log and photographs as the job progresses.

Trust your instincts. Persistent pressure to pay a large deposit in cash, reluctance to provide a written quote, refusal to supply an insurance certificate, a discount that expires today, or a contract in someone else's name are all reasons to pause. A reliable builder will welcome your questions — they have nothing to hide, and a well-briefed client usually means a smoother job for everyone.