A quote that says guaranteed tells you very little. Guaranteed by whom, for what, and for how long? On a new roof the answers can be three separate documents, and a gap between them is where disputes begin.
This guide sets out the three kinds: a workmanship guarantee from the roofer, a materials warranty from the manufacturer and insurance-backed cover that sits behind the first. It covers what each commonly includes and leaves out, what to ask for in writing, and why a guarantee period is not a prediction of how long the roof will last. Lifespan figures come from published sources and always depend on exposure, workmanship and upkeep.
If you are weighing one firm against another, our guide to choosing a roofer in Stroud deals with the wider checks. What happens to a guarantee when a house is sold has its own page: does a roof guarantee transfer? Here we stay with what the types are. Supreme Roofing Stroud gives its terms in writing before work starts.
Three promises, three parties
Before reading any document, find out who is making the promise. The party matters because it decides who you chase, and whether they will still exist when you need them.
| Type | Made by | Normally covers |
|---|---|---|
| Workmanship guarantee | The roofing firm | Faults in how the work was done |
| Manufacturer's materials warranty | The maker of the tile, slate, membrane or system | Defects in the product itself |
| Insurance-backed cover | An insurer, arranged through the contractor | The contractor's promise, if the firm cannot honour it |
Why the split matters
A slate that splits in the quarry is the maker's problem. A slate that slips because it was nailed badly is the roofer's problem. A roofer who has closed down leaves a hole in the first promise unless a third party stands behind it. Each document answers only one of those situations, and none of them answers all.
Many failures need sorting before anyone can say who is responsible. A leak may be a faulty membrane, a poor weld on the laps or a blocked outlet that was never the roof's fault. That is why an independent look at the cause matters before blame is placed.
Workmanship guarantees: what the roofer promises
A workmanship guarantee is a written promise from the roofing firm that its labour will be free from fault for a stated period. It is the document most people have in mind when they say a roof is guaranteed.
What it normally covers
Typically it covers faults in the fixing and laying: slates or tiles that were not secured properly, flashings that were badly dressed, ridge and verge work that comes loose, laps in a flat roof that open. If the defect comes from the work, the firm puts it right at its own cost during the period.
What it usually excludes
Exclusions are where the detail lives. Look for storm damage, impact, moss and debris, lack of maintenance, work by other trades on the roof, damage from someone walking on the covering and defects in the materials themselves. An exclusion for failure to maintain can matter: if the guarantee expects gutters to be cleared and flat roofs to be checked, keep records. Our roof maintenance checklist shows what regular upkeep looks like.
Our own terms
Supreme gives a 10-year workmanship guarantee, in writing, for the work we carry out. It covers our labour and fixing. The period is the length of the promise on our work, and tells you nothing about the life of the covering itself. We set out the exact wording before any work begins, so you can read it alongside the itemised quote.
A workmanship guarantee is only as sound as whoever stands behind it. Check the term, the exclusions and the name of the person you would ring.
Manufacturer warranties: what the product maker promises
A manufacturer warranty comes from the company that made the tile, slate, membrane or system. It is a promise about the product, not about how it was fitted.
What the product promise covers
It usually covers a defect in the material that makes it fail in normal use within the warranty period: a tile that delaminates, a slate that sheds layers or a membrane that cracks without outside cause. The remedy is often replacement of the faulty product, sometimes with a contribution to labour and sometimes without.
Conditions that can void it
Warranties carry conditions. Many require that the product is installed to the maker's instructions, with the right underlay, battens, fixings and ventilation, and that it is used on a pitch within its limits. Natural slate has pitch rules set out in BS 5534, and tiles have manufacturer minimums. Fix the product wrongly and the warranty can fail even though the product is sound. Some makers require the installer to register the job. Keep the paperwork and the delivery notes.
How long they run
Periods vary a great deal. Less says manufacturer warranties of 20 to 25 years are standard for EPDM flat roofing. The zinc maker VM Zinc says its material warranty can run up to 50 years on a project-by-project basis. A long warranty on the product still says nothing about the labour, so ask for both documents.
Warranties and the registration step
Some warranties only begin once the roofer registers the job with the manufacturer. If a document arrives weeks after the work, check it names your address and the product used.
Insurance-backed guarantees: a safety net behind the roofer
Insurance-backed cover adds a third party. The roofer's promise is covered by an insurer, so that if the firm stops trading, the cover can still respond. It is a protection against the roofer disappearing, not a longer or stronger promise about the roof.
What it generally does
Where it exists, it is usually arranged by the contractor for each job, with a certificate issued in the homeowner's name. The certificate sets out what is covered, the period and how to claim. It is only as broad as its terms, and those vary between schemes.
What to check
Ask who the insurer is, what the policy covers and for how long, whether the cover applies only if the firm has become insolvent, what the claim process is and whether there are limits or excess charges. A certificate that names a scheme is not enough on its own: read what the scheme actually promises. The Association of British Insurers (abi.org.uk) publishes general consumer guidance on insurance if you want background.
Not every job has it
Not every roofing firm arranges one, and a firm that does not may still do excellent work. What matters is that what is being sold is described accurately. If a quote says insurance-backed, ask to see the document. If it says nothing of the kind, the guarantee you have is the workmanship guarantee and the manufacturer's warranty, and you should read them with that in mind.
A guarantee is not a lifespan
The most common mix-up is treating a 10-year guarantee as a 10-year roof. The two numbers describe different things. A guarantee is a contractual period during which a named party will put certain faults right. A lifespan is how long a covering typically lasts in service.
What lifespan figures say
Published lifespans are wide ranges that depend on exposure, workmanship and maintenance. MyBuilder puts natural slate at 80 to 100 years or more, clay tiles at 40 to 60 years and concrete tiles at 30 to 50 years. Marley cites a minimum life expectancy of 60 years for clay tiles and about 60 years for concrete, and stresses that neither figure is a guarantee or warranty of longevity. Cotswold District Council's 2000 guidance says a stone slate roof can easily last 100 years with regular maintenance. Our guide to Stroud roof types sets those figures against the coverings found locally.
How the two fit together
A roof can fail well before its guarantee ends, and the guarantee will respond only if the cause is covered. A roof can also last for many decades beyond any guarantee that was ever issued. A short guarantee is not a sign of a poor roof, and a long one is not a promise of a long life.
Good upkeep protects both
Maintenance affects the lifespan and the validity of the cover. Records of gutter clearing, moss control and inspections show you took reasonable care, which helps if a claim is made.
Reading a long number sensibly
When a flat-roof firm offers a 20-year manufacturer warranty on EPDM, set it beside the published range of 20 to 30 years or more for the membrane. The two sit close together, which tells you the warranty is roughly the expected service life, not a margin beyond it. A natural slate roof can have a short workmanship guarantee and still serve for generations, because the stone is sound and the fixings are maintained. Judge each document on what it covers and who stands behind it, not on the size of the figure printed at the top.
What to get in writing before you sign
Verbal assurances do not survive a dispute. Whatever the type, ask for the document before work begins, and read it.
- The name and address of the party giving the guarantee, and how to contact them.
- Exactly what is covered: labour, materials, or both, and which parts of the roof.
- The start date and the length of the period, and what starts the clock.
- What is excluded, including storm damage, lack of maintenance and later work by others.
- What you must do to keep it valid, such as records or notifying a fault within a set time.
- How to make a claim, and who inspects the fault.
- Whether it can be passed on if the house is sold.
Match the paperwork to the quote
The guarantee should refer to the same job as the itemised quote, so the products named in one appear in the other. A line that says approved materials is not a description. If the quote says a particular slate or a membrane by name, the manufacturer's warranty should be for that product.
Disputes and next steps
If something fails inside the period, write to the party named in the document, describe the fault, attach dated photographs and keep a copy. Ask for an inspection and for the reason in writing if a claim is refused. If it is not resolved, Citizens Advice gives general guidance on consumer disputes. Do not let a second contractor start repairs before the first has seen the fault, as that can give the guarantor grounds to decline.
Keep your records
Store the quote, the guarantee, photographs of the roof before and after, delivery notes and any building control certificate together. We photograph your roof at the survey and again when the work ends, and we leave the site clear of waste. If you are a leaseholder or share a roof, check who is responsible for claims.
Call 01453 933613, use WhatsApp or the enquiry form, and ask for our guarantee wording ahead of any survey.