A roof guarantee is only worth as much as what stands behind it. A standard workmanship guarantee typically covers installation for 1–10 years and dies with the contractor if they go out of business, while an insurance-backed guarantee (IBG) — the roof guarantee certificate worth actually asking for — keeps that promise alive for 10 years even if the roofer doesn’t. What’s covered also depends heavily on the roof type: GRP and EPDM flat roofs carry much longer manufacturer warranties than a standard pitched roof. This guide covers what to expect and what to check before you accept one.
A roof guarantee certificate is the written document a roofer issues confirming they’ll fix workmanship faults for a set period after the job, and it’s the paper trail you’d need if you ever had to make a claim or sell the house. On its own, it’s only as reliable as the company that issued it — which is exactly the gap an insurance-backed guarantee is designed to close.
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A standard roof guarantee is a promise from the contractor alone, and it’s worthless if that company stops trading before the guarantee period ends. An insurance-backed guarantee (IBG) is, per the Confederation of Roofing Contractors’ guide to insurance-backed guarantees, “an insurance policy that will honour the terms of the guarantee you provide to your customers for both materials and workmanship should your business cease trading” — covering the same faults, but backed by an insurer rather than a company that might not exist in five years.
A standard workmanship guarantee typically runs 1–5 years, with some contractors offering up to 10 years on installation quality — but an insurance-backed guarantee runs a fixed 10 years regardless of the contractor’s fate, since per the CORC guide above “all policies provide coverage spanning 10 years” and cover up to £250,000 of contract value. Manufacturer material warranties on the roofing product itself are separate again, and usually run much longer than either.
| Guarantee Type | Typical Length | Covers |
|---|---|---|
| Standard workmanship guarantee | 1 – 10 years | Installation faults, tied to the contractor |
| Insurance-backed guarantee (IBG) | 10 years | Workmanship + materials, survives contractor closing |
| Felt roofing manufacturer warranty | 10 – 20 years | Material defects |
| EPDM rubber roof warranty | 20 – 30 years | Material defects |
| GRP fibreglass roof warranty | 20 – 40 years | Material defects |
A flat roof should carry a materials warranty matched to the system used, since flat roof coverings vary hugely in expected lifespan. Per the Checkatrade fibreglass roof cost guide, a well-maintained GRP fibreglass roof will “last for at least 25 years — if not longer,” and manufacturer warranties on GRP systems typically reflect that with 20–40 year cover, well beyond a standard felt roof’s 10–20 years; our guide to flat roof repair, common problems and cost covers the material choice itself in more detail.
No — a GRP guarantee usually covers material defects and correct installation according to the manufacturer’s specification, not damage from something falling on the roof, standing water caused by poor falls being ignored, or work carried out by someone other than an approved installer. It’s worth checking exactly what voids a GRP warranty before assuming a 20–40 year figure applies automatically to your roof.
If you only have a standard workmanship guarantee, a contractor going out of business usually means the guarantee becomes unenforceable — there’s no one left to make the claim against. With an insurance-backed guarantee, per the CORC guide above, cover continues because it’s “protected if the roofing business stops operating due to liquidation, receivership, administration or winding up,” so the insurer honours the claim instead of the (now nonexistent) roofing company.
Yes, on any job of real value — an IBG typically costs from around £45 according to the CORC guide above, a small amount against a roof that might cost several thousand pounds, and it’s usually the difference between a guarantee that’s actually worth the paper it’s printed on and one that’s a gamble on the contractor still existing in a few years. Before appointing anyone, our guide on how to hire a roofer and our guide on checking a roofer is licensed and insured both cover what else to verify before work starts.
A proper quote should say clearly what type of guarantee is included, how long it lasts, and whether it’s insurance-backed or just a company promise — a job with no guarantee mentioned at all usually means it hasn’t been decided yet. JW Roofing Solutions provides an insurance-backed guarantee on qualifying work across SouthWest London, alongside our full range of roofing services. Every quote is written, detailed and free with no obligation.
Get a free, no-obligation roofing quote from JW Roofing Solutions — we’ll tell you honestly what guarantee applies to your job and give you a clear written price either way.
What is a roof guarantee certificate?
The written document confirming a roofer will fix workmanship faults for a set period — the paper trail needed for a claim or when selling the house.
How long does a roof guarantee last?
A standard workmanship guarantee typically runs 1–10 years. An insurance-backed guarantee runs a fixed 10 years regardless of what happens to the contractor.
What is a flat roof guarantee, and how long should it last?
It’s the materials warranty on the flat roof covering used — typically 10–20 years for felt, 20–30 years for EPDM rubber, and 20–40 years for GRP fibreglass.
Does a GRP roof guarantee cover everything?
No — it usually covers material defects and correct installation, not accidental damage or standing water caused by ignored drainage issues. Check what voids it before assuming full cover.
What happens to my guarantee if the roofer goes out of business?
A standard guarantee usually becomes unenforceable. An insurance-backed guarantee continues, since an insurer — not the contractor — honours the claim.
If you’re not sure what guarantee applies to a job you’re considering, contact JW Roofing Solutions for a free, honest assessment and a written quote covering your SouthWest London property.
