Extensions are generally larger, high-value jobs, and homeowners are more cautious about them. So while there’s no blanket law, the Insurance Backed Guarantee comes up often. And knowing when you need one, and how it differs from a structural warranty, is what this guide is for.
Is an Insurance Backed Guarantee compulsory for extension builders?
Generally, no.
General building and extension installations aren’t governed by a Competent Person Scheme that forces an Insurance Backed Guarantee on every job, the way domestic glazing is – yet. So in most cases it’s your choice.
It becomes effectively required in two situations: if you’re in a scheme that mandates financial protection — TrustMark-registered businesses must provide a minimum two-year guarantee — or if a specific contract or client asks for one. Plenty of homeowners now do.
Why extension builders provide one anyway
Put yourself in your customer’s shoes. They’re spending tens of thousands and living through months of disruption. One of their big fears is a half-built extension and a builder who’s ceased trading. An Insurance Backed Guarantee answers that fear directly: if your company ceases to trade during the term, a valid claim against your guarantee still gets put right — subject to the terms and conditions of the policy.
On a job this size, that reassurance wins work. It’s often the difference between the homeowner choosing you and choosing the firm that offered it.
Insurance Backed Guarantee or structural warranty — which do you need?
This often trips builders up, so it’s worth covering. They’re different products that solve different problems, and a large project can call for both.
| Insurance Backed Guarantee | Structural warranty | |
|---|---|---|
| What it protects | Your own workmanship guarantee | The building’s structural integrity |
| When it pays | If your company ceases to trade during the term | For structural defects, regardless of whether you’re still trading |
| Typical length | Mirrors your guarantee, up to the policy maximum | Usually 10–12 years |
| Often needed for | Reassuring homeowners; scheme membership | New dwellings and major work; sometimes required by lenders |
For a full breakdown, see our guide: Insurance Backed Guarantee vs structural warranty.
Does an Insurance Backed Guarantee replace building control?
No. Building control (through your council or an approved inspector) confirms the work meets Building Regulations.
An Insurance Backed Guarantee is separate. It backs your company written guarantee if you cease trading as per the policy terms and conditions. You still need building control sign-off on an extension. The Insurance Backed Guarantee sits alongside it, not instead of it.
Want the protection homeowners look for before they commit to a big build?
HomePro provides Insurance Backed Guarantees for extension and general builders, plus the badge and reviews that win bigger jobs. Call 0800 131 0500 (Mon–Fri, 9am–5pm) or join here.
Frequently asked questions
Is an Insurance Backed Guarantee a legal requirement for extension builders?
Usually not. There’s no blanket law. It’s effectively required only through a scheme like TrustMark, or where a specific contract or client asks for one.
Is it the same as a structural warranty?
No. A structural warranty covers the building’s structure for 10–12 years regardless of your status. An Insurance Backed Guarantee backs your workmanship guarantee and pays if your company ceases trading. A big project may need both.
Does it replace building control?
No. Building control confirms Building Regulations compliance. The Insurance Backed Guarantee is separate and sits alongside it.
Who pays for it?
You pay the premium and build it into your price. The homeowner is the policyholder but doesn’t pay for it separately.
Join UK installers who provide FCA-regulated Insurance Backed Guarantees with every job through HomePro. Call 0800 131 0500 or join the HomePro network today.
Disclaimer: This post is for general information only. It is not financial, legal or insurance advice. While we take care to make sure the information is accurate, scheme rules, legal requirements and third-party details can change without notice — always check the latest position with the relevant scheme or official body before acting on anything here. HomePro accepts no liability for any loss arising from errors or omissions in, or reliance on, the information in this article. Insurance Backed Guarantees are subject to the terms, conditions and limitations of the individual policy.
