Risk-based assessment
Many surveyors and lenders use a risk-based framework to assess the implications of Japanese knotweed at a property, based primarily on proximity to habitable structures and property boundaries. The categories used may vary between surveyors and lenders.
Proximity to structures
The implications of knotweed vary depending on whether it is within the property boundary, how close it is to habitable structures, and whether there is evidence of damage. Growth immediately adjacent to foundations is typically assessed as presenting higher risk.