RICS Categories for Japanese Knotweed

The Royal Institution of Chartered Surveyors (RICS) categorises Japanese Knotweed risk from A to D, based on severity and proximity to a property.

Some of the descriptions below have been simplified to give a brief insight rather than a detailed description especially when mortgage lenders have such a variety of policy. For more information click on this link.

Category A:
Visible damage is present. Most lenders won’t lend unless a specialist inspection and a Knotweed Management Plan with an insurance-backed guarantee is in place. Property value is likely affected.

Category B:
Knotweed restricts use of amenity space. Lenders typically require a specialist assessment and treatment plan with a guarantee. Property value may be impacted.

Category C:
No structural damage or serious restriction, but growth is within 3m of a boundary. Lenders may still recommend a specialist assessment. Value impact is usually minor.

Category D:
No knotweed on-site, but it’s present on neighbouring land. There's a risk of future spread. Remediation of off-site knotweed is outside the property owner's control, so lenders shouldn't require it. Value is rarely affected unless extensive encroachment poses future legal or remedial risks.

Summary:
Japanese Knotweed doesn’t always mean you can’t get a mortgage. Risk level, treatment, and expert advice can make all the difference when buying or remortgage a property.