How to choose a garden room builder

Start with three written quotes

TrustMark, the government endorsed quality scheme for work in and around the home, advises getting at least three quotes. Do not just pick the cheapest.

Give each builder the same brief: the size, the use, the finish and the services. Then compare the quotes line by line. A low quote that leaves things out is not low. Use the garden room cost calculator and how a price is built to see what a full quote should cover.

We match you with up to 3 local builders. It is free for homeowners. You still choose.

Questions to ask every builder

• Have you built rooms like mine in my town? Can I see one, and speak to the owner?
• Who does the work: your own team, or sub-contractors? Who is on site each day?
• Do you visit the plot before you quote?
• What is in the price and what is not? Ask about the base, the electrics, the groundworks, waste removal and the finish.
• Who checks the planning rules for my plot? See planning permission.
• Will building regulations apply, and who handles them? See building regulations.
• Who does the electrics? Are they registered with a competent person scheme, and will I get a certificate? See garden room electrics.
• What is the start date and the build time? What happens if you run late?

Insurance

TrustMark tells homeowners to check that a tradesperson is insured. It does not say which policies. Ask the builder to show you the certificates, and check the name, the dates and what is covered.

• Ask what cover they hold if something is damaged on your property.
• Ask what cover applies to the people working for them.
• Ask whether your own home insurer needs to be told. Tell them about the room once it is built.

We do not set a minimum amount. Ask your insurer what they expect.

Guarantees and warranties

TrustMark says to understand guarantees and aftercare. Get the paperwork before you sign.

• Who gives the guarantee: the builder, the manufacturer, or a third party?
• What does it cover: the structure, the roof, the cladding, the glazing, the electrics?
• How long does it last for each part?
• What must you do to keep it valid, such as oiling the timber?
• What happens if the builder stops trading?

Guarantees from a builder are only as good as the builder. Ask whether the cover is insured or backed by a third party.

The contract and payments

• Get a written quote and contract that lists the specification, the price, the start date and the build time.
• Agree changes in writing.
• Link payments to stages of work. Be careful with a large deposit up front.
• Keep copies of everything, including the certificates. They help when you sell. See does a garden room add value.

Checks you can do yourself

• Search the TrustMark register for the builder, if they are a member.
• Ask for references and call them. Ask whether the work was on time, on budget and tidy.
• Look at finished rooms. Ask the owners what they would change.
• Look at how the builder answers. Clear, written answers are a good sign. Pressure to sign today is not.

If things go wrong

GOV.UK says the law protects your consumer rights when you buy services, and that you can get help if you are treated unfairly or when things go wrong. Building work is on its list of problem areas. Citizens Advice runs a helpline for England and Wales, and Which? has information on refunds and repairs. Raise a problem in writing and keep the record.

Local builders

Ask builders in your own town. We cover Berkhamsted, Hemel Hempstead, Amersham, Aylesbury and more. A builder who works near you knows your council. For the room itself, see garden offices, garden gyms, garden studios and garden annexes.

Warning signs

• No written quote, or a quote with no breakdown.
• Pressure to sign or pay today.
• A very large deposit, or payment in cash only.
• No insurance certificates, or an unwillingness to show them.
• No references, no finished rooms to see, and no address.
• Vague answers on planning, building regulations and electrics.
• A promise to do it all without checking your plot.

One warning sign is a reason to ask more. Several is a reason to walk away.