How to check a builder before you hire them

Why checks matter

Most builders do honest work. But because building work is expensive and hard to undo, a little checking before you commit is worth the time. The goal isn't to catch someone out — it's to make sure you know who you're dealing with.

1. Confirm who the business is

Get the full business name, a physical address and a landline or mobile number.

• Limited companies can be looked up on the free Companies House register. Check the company is active and the address matches.
• Sole traders won't appear there, so a verifiable address and a track record matter more.

Be cautious if a trader only offers a first name and a mobile number.

2. Look at recent, comparable work

Ask for examples of similar jobs completed recently, ideally nearby.

• Ask if you can speak to two or three past customers.
• If possible, see finished work in person.
• Online reviews help, but look for detail and patterns rather than star ratings alone.

A builder who has done great kitchens may not have done a two-storey extension. Relevance matters.

3. Check insurance

Ask to see:

• Public liability insurance, covering damage or injury caused during the work.
• Employer's liability insurance, if they employ staff — this is a legal requirement for most employers.

Check the policy dates and the level of cover. If the work is substantial, ask whether the work itself is covered by any guarantee.

4. Verify trade schemes and registrations

Some work needs specific registration:

• Gas work must be done by someone on the Gas Safe Register.
• Electrical work in homes often falls under building regulations; registered competent persons can self-certify.
• Replacement windows can be self-certified by installers registered with a competent person scheme.

Membership of schemes such as TrustMark can also be checked online. Always verify on the scheme's own website.

5. Get a detailed written quote

A good quote lists the work, the materials, the price, VAT, timescales and payment terms. If quotes from different builders vary wildly, our guide on why builder quotes differ helps explain why.

6. Watch the conversation

How someone communicates before the job is often a guide to how they'll communicate during it. Pay attention to:

• Whether they answer questions clearly.
• Whether they visit to look properly before quoting.
• Whether they pressure you to decide quickly.

A short checklist

1. Full business name and address confirmed.
2. Companies House checked (if a limited company).
3. Two or more recent references spoken to.
4. Insurance certificate seen and in date.
5. Scheme memberships verified directly.
6. Detailed written quote received.

Next steps

Once you have two or three checked builders, compare their quotes on more than price. Estimo's quote comparison helps you line up scope, terms and price side by side.

Sources

• Companies House — search the register
• Gas Safe Register
• TrustMark