New heatmap pinpoints Japanese knotweed hotspots – Throughout London & Hertfordshire

A Japanese knotweed tracking tool has been created to help professionals involved in residential transactions build a picture of local sightings and potential risks

The tool – named named Exposed: The Japanese Knotweed Heatmap  – has been produced by removal specialists Environet. It is based on ‘sightings’ of the problem plant, some verified by the firm and others simply reported by members of the public.

The firm suggested the tool will be an “invaluable source of information to property professionals” as it will help them work out how likely a property deal is of being affected by issues arising from the plant.

Research from the firm last year suggested that Japanese knotweed has wiped as much as £20bn off the value of property in the UK.

Lenders are often unwilling to offer mortgages against properties affected by the plant, unless there is some form of plan for dealing with it in place, due to concerns over how quickly it can grow and the damage it can do to buildings as a result.

However, research published last year suggested lenders should be more lenient as its structural impact may be much less than originally believed.

Anyone can report a sighting of Japanese knotweed, through their mobile phone. They just need to go to the heatmap, click the ‘add sighting’ option, and then zoom in on the satellite view.

They’ll be asked to define the size of the infestation, with no sign in or passwords required. Environet said that wherever possible it will look to verify new sightings in order to keep the heatmap as up-to-date as possible.

Nationwide picture

Nic Seal, founder and managing director of Environet, said the heatmap would enable the firm to build a nationwide picture of the Japanese knotweed problem and help property professionals to assess the risk locally when dealing with transactions.

He continued: “High-risk results should prompt further investigation with an on-site Japanese knotweed survey. The site is already well populated, but this is an ongoing project.

“The more people who report sightings, the more effective it will become.”

Brian Sullivan MRICS, FCABE – St Albans and London

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