New valuation tool launched for properties blighted by Japanese knotweed

24 July 2019: A new valuation tool for assessing the value of properties affected by Japanese knotweed has been developed by Environet UK, with support from Expert Surveyors Limited, a leading provider of RICS expert property valuation reports in the UK.

JK-VIM, a free online tool, enables surveyors, estate agents and property owners to check how much the value of a property may potentially be reduced if it is affected by knotweed. It also offers revised valuations if a property is treated by herbicide or excavation and if it has a ten-year insurance-backed guarantee for the works.

Existing lending practices for properties affected by Japanese knotweed have come under scrutiny following the Science & Technology Select Committee’s enquiry into the impact of Japanese knotweed on the built environment earlier this year, which concluded that the current approach to Japanese knotweed is overly cautious”. This often results in nil valuations, where the property is valued at £0 for lending purposes, when in practice the diminution in value may be no more than 5% – 10% of the unaffected Market Value.

The JK-VIM algorithm allows for a much more nuanced approach, taking into account the size of the infestation and the distance to the nearest boundary.

Nic Seal, Founder and MD of Environet, said,

Existing valuations tools for dealing with properties affected by Japanese knotweed are blunt, inaccurate and leave homeowners at the mercy of their neighbour’s action or inaction if knotweed exists on an adjoining property.

In reality, affected properties are typically worth around 10% less than an unaffected property, which reflects the cost of treatment plus the so-called ‘knotweed stigma’.

“JK-VIM offers RICS surveyors an easy to use online valuation tool to assist their own professional judgement based on the facts of the case and guides homeowners on how the value of their property can be preserved if the knotweed is professionally treated or removed.”

Chartered Surveyor Paul Raine, Director of Expert Surveyors Ltd, added:

The Select Committee was right to conclude that lending practices for properties affected by knotweed need urgent review. All that’s required to sell in such cases is a treatment plan and a sensible readjustment of the price. With Japanese knotweed now affecting an estimated 4-5% of homes, JK-VIM is a helpful new tool in our armoury.”

To use JK-VIM, please visit:

Kindly shared by Environet