When you're investing several thousand pounds in a new roof or major roofing work, the guarantee is one of the most important parts of the package. But the word "guarantee" gets used loosely in the building trade, and it's worth understanding exactly what it means — and what it doesn't — before you sign anything.
CMW Repairs Ltd offers a 15-year workmanship guarantee on all roofing installations and major repairs. Here's a clear, honest explanation of what that covers, what falls outside it, and how it compares to the separate manufacturer warranties that come with roofing materials.
What Is a Workmanship Guarantee?
A workmanship guarantee is a promise from the roofing contractor — not the tile or membrane manufacturer — that the work has been carried out correctly and will perform as expected for the period stated. If a defect arises that's attributable to how the roof was installed, the contractor commits to returning and rectifying it at no cost to you.
This is distinct from a manufacturer's product warranty, which covers material defects. The two work alongside each other but are separate commitments from separate parties.
What CMW's 15-Year Guarantee Covers
Our 15-year workmanship guarantee applies to the quality of the installation itself. Specifically, it covers:
- Leaks caused by installation errors. If water enters through the roof in a way that's attributable to how we fitted the tiles, membrane, flashing, or any other component, we will return and remedy it at no cost.
- Tile or slate slippage due to incorrect fixing. Tiles and slates that slip, slide, or lift because they weren't correctly nailed or clipped at the time of installation are covered.
- Flashing failures caused by workmanship. Lead or Code 4 flashing around chimneys, valleys, abutments, and dormers that fails because of how it was fitted, not because of material degradation beyond its expected lifespan, is covered.
- Ridge and verge defects. If ridge tiles crack, lift, or separate from the roof due to the way they were bedded or pointed, that's covered.
- Flat roof membrane failures attributable to installation. On GRP fibreglass roofs, delamination, cracking, or leaking caused by incorrect lamination or substandard application of the resin is covered.
What the Guarantee Does Not Cover
Being honest about exclusions is just as important as being clear about what's included. Our guarantee does not cover:
- Storm damage or acts of God. If a tile is blown off by an unusually severe storm, or a tree branch damages the roof, that's a matter for your home insurance, not our guarantee. Normal wind and weather resistance is built into how we install, but extreme events are not within any contractor's control.
- Damage caused by third parties. If someone else carries out work on or near the roof after we've completed our job — fitting a satellite dish, adding a dormer, or making modifications — and this causes a problem, that falls outside our guarantee.
- Normal wear and material ageing. All roofing materials have a finite lifespan. GRP topcoats eventually need refreshing; lead flashing oxidises over decades; ridge mortar weathers over time. These are expected maintenance items, not installation defects.
- Issues caused by neglect or lack of maintenance. Blocked gutters that cause water to back up under the eaves, or blocked outlets on a flat roof that result in pooling, are maintenance matters. Keeping gutters clear and flat roof outlets unblocked is the homeowner's responsibility.
- Pre-existing structural issues. If there is a pre-existing problem with the roof structure — rotten rafters, a sagging deck — that we identified at the time and noted in writing, any consequential issues that arise from that are not covered by our workmanship guarantee on the new roof covering.
How Does It Differ from Manufacturer Warranties?
When we fit a new tiled roof, the tiles themselves may carry a manufacturer's guarantee — often 30 to 50 years on premium concrete or clay tiles. For GRP flat roofs, the resin system manufacturer typically provides a product warranty of 20 to 25 years when applied by a trained installer.
These manufacturer warranties cover defects in the materials themselves — a tile that cracks abnormally, a membrane that degrades prematurely due to a product fault. They do not cover installation errors. That's what our workmanship guarantee covers. Together, the two guarantees give you comprehensive protection: if the material fails, the manufacturer's warranty responds; if the installation fails, ours does.
Why 15 Years Matters
Many roofers offer guarantees of 5 or 10 years. A 15-year workmanship guarantee is significantly longer than the industry average, and it matters for a straightforward reason: it demonstrates confidence in the quality of the work.
A contractor who offers a 12-month guarantee is, whether they intend it this way or not, only committing to fixing obvious problems that surface immediately. Most installation defects — gradual water ingress, slow tile movement, subtle flashing failures — take several years to manifest. A 15-year guarantee means we're standing behind the quality of our work through the period when most issues, if any exist, will come to light.
Is the Guarantee Transferable?
If you sell your home within the 15-year guarantee period, the guarantee can be transferred to the new owners. We provide all guarantees in writing, and a copy is kept on file. If you've misplaced your documentation, contact us and we can reissue it.
How to Make a Guarantee Claim
If you believe a defect covered by the guarantee has arisen, simply contact us. We'll arrange a site visit, inspect the issue, and determine whether it falls within the guarantee scope. If it does, we'll carry out the remedial work at no charge. We aim to respond to guarantee claims within 5 working days, with urgent cases (active leaks) prioritised.
Ready to get started with a roofer who backs their work for the long term? Contact CMW Repairs Ltd for a free quote. We cover all of Hampshire from our base in Southampton, and every job we do comes with our 15-year workmanship guarantee in writing.