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What does it cost to treat or excavate Japanese knotweed?

What does it cost to treat or excavate Japanese knotweed?


Chartered Surveyor Paul Raine, Managing Director of Expert Surveyors Ltd, unveils a helpful new online tool, providing guidance to surveyors and other property professionals on the current indicative costs of treating Japanese Knotweed – either by excavation or herbicide treatment.

Paul advises: Our group of surveyors conduct thousands of residential property surveys and valuations throughout England and Wales every year. Inevitably, some of those properties surveyed are affected by Japanese Knotweed. In those cases, we are often asked what it costs to treat Japanese knotweed on these properties, typically for buyers who want to renegotiate the purchase price and in a few cases for litigation purposes.

The cost of treatment will typically depend on factors such as the size and maturity of the infestation, the treatment method to be adopted, ease of access to the infested areas for treatment, whether there is any infestation on neighbouring land, the proximity of the infestation to the boundaries and to the house, the physical topography of the site and hard/soft landscaping features on the site. In addition, there is the cost and scope of the insurance-backed guarantees which are required as an essential part of any professional Knotweed Management Plan. The guarantees are essential and must be insurance-backed if you are looking to sell or buy a property infested with Japanese knotweed.

In the course of our work, we have accumulated a substantial database of professional contractor costs from across England and Wales covering a wide range of scenarios and types of property. This provides us with a basis on which to provide general indications of the cost of treatment which no doubt will be helpful to surveyors, solicitors, buyers and property owners.

Obviously, there is no substitute for obtaining a Knotweed Survey and Management Plan, including a quotation from a professional PCA approved knotweed contractor for the actual property as the treatment requirements for each property will be different. However, a ‘broad-brush’ initial indication of cost will be helpful in many situations and that is why we have rolled this data into a simple, free to use online tool for all stakeholders. Our data is based upon industry figures correct for 2019. Users can enter the property address, some details about the size of the infestation and access for machinery, to discover indicative costs for both herbicide treatment and excavation.

The choice of excavation or herbicide treatment will depend on the circumstances of each case and that always requires professional advice, both to optimise the treatment plan and minimise the residual diminution in value to the property which may occur during and after the treatment.

Reproduced with kind permission from Expert Surveyors Ltd.

This tool is designed to offer a first-step indicative price guide for professional Japanese knotweed treatments with an insurance-backed guarantee. It is not intended as a replacement for getting competitive quotations from suitable knotweed specialists such as Environet UK.

We would like to thank Paul Raine for his guest blog. Read more about our herbicide treatments and knotweed excavations or call us on 01932 868 700.

Robert Spaceman

“We had a large stand of bamboo removed, thinned, contained and replaced. The customer service has been first class. Joe and Jason were fabulous and kept me well informed at all times”.