Warranty and reliability
What good warranty terms look like, how to judge a company's reliability, and what to do if something does go wrong after handover.
Short answer
What is a fair warranty?
A fair warranty names structure, waterproofing and finish separately, with clear durations, clear exclusions and a documented process for claims. "Warranty included" without a written document is not a warranty — it is marketing.
What good looks like
Warranty by component
| Component | Minimum term | Good term | Watch out for |
|---|---|---|---|
| Structure | 5 yrs | 10 yrs | Vague phrasing about 'normal use' |
| Waterproofing | 5 yrs | 10 yrs | Excludes lead flashing or sealants |
| Finish (cladding) | 2 yrs | 5–10 yrs | Excludes colour fading |
| Glazing | 5 yrs | 10 yrs | Excludes seal failure |
| Frames | 5 yrs | 10 yrs | Excludes hinges and locks |
| Industry scheme | — | BouwGarant or equivalent | No third-party backing |
Reliability
How to judge the company itself
Checklist
Reliability checks
Checklist
Quick verifications
- 01Chamber of Commerce (KvK) registration matches the company name.
- 02Same address on quote, website, and KvK.
- 03Warranty document received in writing before signing.
- 04Industry warranty scheme membership verified on the scheme's site.
- 05Reviews checked across at least two independent platforms.
- 06References available — and at least one called.
- 07Insurance certificate available on request.
- 08Terms and conditions shared up front.
Read next
Related guides
Quick answers
Frequently asked questions
FAQ
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01What warranty should I expect on a dormer?
At least 10 years on structure, 10 years on waterproofing, and 5–10 years on finish — each listed separately, in writing.
02What happens if the company goes bust?
Look for membership in an industry warranty scheme that covers continuity. Without that, a company's warranty is only as solid as the company itself.
03Are reviews part of 'reliability'?
Yes, but only when combined with documents. Read terms, warranty, references — and then check reviews on multiple platforms as a sanity check.
04What voids the warranty?
Usually: missing yearly maintenance for timber, unauthorised modifications, and damage by third parties. Always read the exclusions section.
Conclusie
A good warranty is short to read, fair to both sides and backed by a company you can still find in five years. Insist on the document; the rest follows from there.