Insurance-backed guarantees for knotweed treatment: what they cover, what they don't
GPI, Brunel, QANW — who underwrites IBGs in the UK, what they include, and how to read the small print.
An IBG sits behind your contractor's own treatment guarantee. If the contractor is still trading, they fix any regrowth at their cost. If they have ceased trading, the IBG underwriter steps in and pays for another contractor to complete the work.
What's covered
- Re-treatment costs if regrowth occurs within the guarantee period.
- Contractor insolvency cover — the underwriter funds a replacement.
- Some products also include limited cover for damage to property caused by treatment failure.
What's not covered
- Knotweed that re-establishes from a fresh source after treatment is signed off.
- Damage caused by the original infestation prior to treatment.
- Treatment that was halted or interrupted by the property owner.
Reading the certificate
Look for three things: the named underwriter, the term, and the explicit assignment clause. If any of those is missing, the IBG is worth less than the paper it is printed on at the point of sale.
Reviewed by
The survey team
PCA-certificated surveyors, Japanese Knotweed Elimination
PA1 / PA6A certificated surveyors who carry out the site visits, write the management plans and sign off the reports issued to lenders and solicitors.
Reviews the technical, legal and lender statements in this article.
What this page can't tell you
- Guidance is general. Identification, treatment choice and timescales can only be confirmed by a site visit — photographs alone are indicative.
- Lender and insurer requirements vary by institution and change over time. We state what is typically accepted, not what any named lender will accept on your case.
- Guarantee (IBG) eligibility depends on the plan chosen, the survey findings and the underwriter's acceptance. It is not automatic.
- Legal points summarise published law and guidance current at the review date. They are not legal advice.
Last reviewed · Questions on anything stated here: 07582 869979
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