Flat Roof Guarantees and Warranties: What Are You Entitled To?

A flat roof is a significant investment. Understanding what guarantee you should receive — and what it actually covers — is essential before any work starts.

Contractor Guarantee vs Manufacturer Guarantee

Most flat roof installations come with two types of guarantee: a contractor workmanship guarantee (typically 10–20 years) and a manufacturer material guarantee from the system manufacturer. The contractor guarantee is only as good as the contractor — check they'll still be trading in 10 years.

What Should Be Covered?

A good guarantee should cover water ingress resulting from material defects or installation faults. Read the exclusions carefully — most will exclude damage from third parties, blocked drains, or structural movement not caused by the roof itself.

Typical Guarantee Lengths by System

• Mineral felt: 5–10 years (contractor guarantee)
• EPDM rubber: 20–25 years material guarantee + contractor workmanship
• GRP fibreglass: 20–25 years material guarantee + contractor workmanship
• Single-ply membrane: 20+ years

Insurance-Backed Guarantees

The gold standard is an insurance-backed guarantee (IBG). These are provided by third-party insurers and protect you if the contractor goes out of business. They typically cost the contractor a small premium and are a mark of confidence in their work.

What to Ask Before Work Starts

Ask for the guarantee in writing before signing. Check whether it's insurance-backed. Clarify what maintenance is required to keep it valid — many guarantees require annual inspections or regular clearing of drains.