The biggest financial damage caused by Japanese knotweed is to buildings and the mortgages secured against them. A knotweed infestation can damage the structure of a building, plunging the owner into negative equity and creating unsustainable risk to the lender.
For this reason, as recently as five years ago, almost all mortgage lenders would refuse to lend if there was any evidence of knotweed on the property.
In the past five years, however, the Royal Institute of Chartered Surveyors has produced guidance on the subject, allowing surveyors and lenders to better understand the problem and what can be done about it.
Today, therefore, most lenders will take a more considered, case-by-case approach based on knotweed severity, proximity, history and management strategy. If a specialist surveyor attends the site and provides a professional solution, the bank or building society will be able to assess the risk from a more informed position.
Click here for a full breakdown on the law around Japanese knotweed.
An infestation of Japanese knotweed affects the entire ecosystem of any area where it takes hold. Its roots choke out other flora meaning that other plants cannot grow.
Additionally, in times of drought knotweed will suck all of the moisture out of the soil, which removes its binding effect. This can cause extensive soil erosion, with catastrophic results such as riverbanks being washed away.
Japanese knotweed is not poisonous so there is no danger when touching the plant. However, its destructive properties can lead to danger to health and safety. In worst-case scenarios, an infestation can cause subsidence and structural damage to buildings, which can lead to collapse. It can also grow through pipes and therefore has the potential to damage utilities supplies (such as gas, water and electricity) or cause leaks.
Using our survey, the remediation process is a simple one if you use a reputable partner.
You can see more about what a remediation partner will do when treating Japanese knotweed.