It’s advisable to employ a Japanese knotweed surveyor if you’re selling or purchasing a property that has been afflicted by Japanese knotweed so they can carry out a professional Japanese knotweed survey.

To help understand and categorise the level of risk that the knotweed presents to the property, the Royal Institution of Chartered Surveyors (RICS) has created a “risk” table (see the table below).

The level of risk is defined by the proximity of the knotweed to the habitable area or the property boundary and if any structural damage has been caused.

RICS and Japanese Knotweed

The Royal Institute of Chartered Surveyors (RICS) offer information on Japanese knotweed in their paper called ‘Japanese knotweed and residential property.

The primary purpose of this paper was to help people who own plots of land or property that are infested with Japanese knotweed and prevent lenders from immediately denying mortgage applications due to the discovery of Japanese knotweed.

RICS Japanese Knotweed Risk Categories

The RICS Japanese Knotweed information paper explains the background to Japanese knotweed in the UK, considers how lenders have different policies on dealing with its presence, describes the effective treatment and includes an assessment framework.

It is also important to bear in mind that a habitable space refers to any section of the property that could be used for cooking, eating, living or sleeping such as a bedroom, kitchen, sitting room or conservatory, for example.

One effective way to do this is to categorise each case into one of many established risk groups, each with varying degrees of severity. Investigations by a suitably trained and licenced ecologist in the form of a Japanese knotweed survey may or may not be required, depending on the category.

The four categories of risk are as follows:

Japanese knotweed Risk category 5Japanese knotweed risk categories (4 being the highest risk)Japanese knotweed is more than 7 metres away from habitable space, conservatory and/or garage, either within the boundaries of this property or in a neighbouring property or space;
Japanese knotweed is causing serious damage to outbuildings, associated structures drain, paths, boundary walls and fences and so on.
Further investigations by an appropriately qualified and/or experienced person are required.
Japanese knotweed Risk category 4Although Japanese knotweed is present within the boundaries of the property, it is more than 7 metres from a habitable space, conservatory, and/or garage. If there is damage to outbuildings, associated structures, paths and boundary walls and fences, it is minor.
Further investigations by an appropriately qualified and/or experienced person are required.
Japanese knotweed Risk category 3Japanese knotweed was not seen within the boundaries of this property, but it was seen on a neighbouring property or land. Here, it was within 7 metres of the boundary, but more than 7 metres away from the habitable spaces, conservatory and/or garage of the subject property.
Japanese knotweed Risk category 2 Japanese knotweed was not seen on this property, but it can be seen on a neighbouring property or land where it was more than 7 metres away from the boundary.
Japanese knotweed Risk category 1No presence of Japanese knotweed whatsoever.
Interpreting a Japanese knotweed survey

Based on these categories, the RICS would advise that a survey be carried out if the case of Japanese knotweed falls between categories 4 and 5. For cases that fall between categories 2 and 3, a Japanese knotweed survey may be required, but the decision will be based on the requirements of the client and the professional opinion of the valuer.

Carrying out a Japanese knotweed survey?

As with many of our invasive species surveys, our Japanese knotweed survey is often sites specific, with the cost varying based on the size of the plot of land and the magnitude of the development project.

Due to this, it would be strongly recommended to get in touch and request a quote so we can provide you with a price that is accurate to your needs after we have assessed the scale of the problem.

Where it is appropriate and access is possible, we will use our drone to acquire aerial photos/video to ascertain the extent of the infestation.

The results of the survey will include:

Based on the results of the survey and the recommendations outlined in the report, a Knotweed Management Plan (KMP) can be developed.

A KMP will usually include a thorough strategy for how Japanese knotweed in the specific area will be dealt with, whether it is through the use of herbicide treatment visits, reducing or entirely removing traces of the plant or simply performing inspections to monitor growth.

Knotweed Management Plan Survey
Knotweed Management Plan Survey

Knotweed Management Plan

A Knotweed Management Plan (KMP) proposal will comprise a professional Japanese knotweed identification, a thorough report of our findings, images, a location plan, and confirmation of the knotweed RICS property risk rating.

This will include documentation of any evident indicators of knotweed damage to the buildings, ancillary structures, or hard standing/paving.

The KMP will determine the scope of the problem and, in some cases, locate knotweed in nearby gardens. It will cover the cost of remedial work as well as warranties, allowing you to determine genuine and realistic expenses.

Most mortgage lenders demand evidence that a KMP is in place. Likewise, the Environmental Agency state that a KMP must be created as soon as Japanese knotweed is found on a plot of land that is being used as part of a development project.

*This applies to all mainland English, Scottish, and Welsh counties.

What is contained in the KMP?

When providing a KMP one of the most important elements of the report is the knotweed plan drawing. Such a plan must show the following:

  • The location of knotweed
  • The extent and shape of the land that is visibly impacted by knotweed
  • The extent and shape of the land which will be impacted by knotweed rhizome (roots) is larger than the area that’s visibly impacted
  • The potentially impacted area of land often referred to as the 7m
  • The distance that the visible knotweed is from a dwelling, garage or similar building
  • The plan should be to scale or scalable
  • The extent of the subject property, ie the area that the report is referring to must be defined.

Typical Japanese Knotweed Survey Costs?

We offer free Japanese knotweed surveys (Virtual) to homeowners. We then write a Knotweed Management Plan (KMP) that our clients can rely upon as an independent assessment of the Japanese knotweed problem. 

Typically residential KMP range from £165 to £365 + VAT.

This is available as a stand-alone product or as part of a treatment package.

We also make customers aware that they can begin the treatment package with just a findings report, which can then be upgraded to a KMP during the treatment programme, which is ideal for people who know they need a specialist to treat their knotweed but don’t need the cost of a KMPS or the assurances of not having to sell their home. 

For home buyers, we offer findings reports which start from £245 + VAT. This is a simple survey and letter to confirm whether knotweed is present on site.

For commercial surveys for Japanese knotweed, we would suggest that you should expect to pay in the region of £600 plus for a site appraisal and finding report for a typical site with one or two stands of knotweed. 

Do I have to declare Japanese knotweed?

The law around Japanese Knotweed changed in 2014. You should report certain non-native species on the Non-native Species Secretariat (NNSS) website.

To avoid any chance of litigation or possible legal issues, it is best, to be honest, and report your findings when you discover Japanese knotweed on or near your property.

What are the Benefits of a Survey with us?

  • The sooner you can identify that you have Japanese Knotweed on your property and begin treatment, the better. Because the expense of treatment will rise as it grows and spreads, you should not delay in identifying and treating it.
  • Mortgage lenders recognise our surveys, which will save you time and money in the long run.
  • When buying land to develop, a survey can protect you by allowing you to include the cost of removal in your offer price; this is also true when buying property.
  • As part of our identification procedure, we will assess the scope of the problem in relation to any anticipated development plans and examine any unchecked plant growth.
  • For each property, land, and/or site, different treatment and removal methods are recommended, and a report will ensure that a complete treatment plan is provided. Our studies are unique, and our treatment plans are based on the time of year, the state of the site, the amount of land available, the timeframes, the proximity of other properties, and the location of the property.
  • With the comprehensive Knotweed Management Plan documents comes a full remedial proposal.
  • Identifying it during the winter months, when the growing season is dormant, might be challenging. Our knowledge of knotweed allows us to identify it at any time of year.
  • Our reports are mortgage-compliant, allowing mortgage lenders and home buyers to comprehend the scope of the knotweed infestation.
  • We will advise you on the threats to any buildings, structures, and the boundaries of your property, as well as the level of risk involved.
  • Our reports are written in an easy-to-understand format.
  • Our report contains a full quotation as well as our proposed Knotweed Treatment Program (treatment proposals) that is tailored to your home, land, or site.

Qualified and experienced specialists

All our contractors have some form of qualifications and/or accreditation. The following is a sample of the most ones:

  • City & Guilds NPTC Level 2
  • Principles of Safe Handling & Application of Pesticides (PA1/PA6)
  • Principles of Safe Handling & Application of Pesticides near water (PA6AW)
  • Herbicide Stem Injection
  • Member of the Property Care Association
  • The Control & Eradication of Japanese Knotweed Surveyor’s Training Course
  • Qualified Technician (PCAQT) in Japanese Knotweed
  • Accredited Surveyor in Japanese Knotweed

Want to know more about a Japanese knotweed survey?

Knotweed Removal aims to provide the most up-to-date information, help and advice for YOU to make informed decisions. If you are unsure or uncertain about how to proceed, please reach out to us and we will gladly come back and advise you as best we can.

Governmental advice can be found here and the UK law covering the removal of Japanese Knotweed as stated under the Wildlife and Countryside Act 1981 can be found here.

The best means to contact us is via our email –

Do not forget we have a library of blogs covering many areas relevant to Japanese Knotweed, our free downloadable How-to Guides and Product Reviews on the latest methods being employed to eradicate or remove Japanese Knotweed.

Knotweed Removal, UK

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