Japanese knotweed · 3 min read
Finding Japanese knotweed when you are selling, or buying, can feel like a disaster. In most cases it is manageable, but it needs to be dealt with properly and documented. This guide gives a general overview. It is not legal or financial advice, so speak to your solicitor, surveyor or lender about your situation.
Do I have to tell buyers about Japanese knotweed?
In England and Wales, sellers usually complete the Law Society's Property Information Form (TA6), which asks whether the property is affected by Japanese knotweed. Answer it honestly and accurately. If you are unsure whether knotweed is present, a professional survey is a better route than guessing.
How surveyors and lenders look at knotweed
In 2022 RICS (the Royal Institution of Chartered Surveyors) updated its guidance on Japanese knotweed and residential property, replacing the old "7-metre rule" with a more detailed assessment of where the plant is and the risk it poses. Lenders set their own criteria. Many will consider a property where the knotweed is under a professional treatment plan with a guarantee, but requirements vary.
What paperwork helps a sale go through
- A survey report identifying the plant and recording its extent, with photos
- A management plan setting out the treatment or removal work, recording each visit
- A guarantee certificate covering the treated area
- Evidence of monitoring visits
Every APC job includes a minimum 5-year guarantee, available for up to 20 years, a guarantee certificate and a management plan that evidences the work from start to finish. Formal CSJK (Certified Surveyor of Japanese Knotweed) survey reports for property sales, mortgages, insurance or legal needs are £240 (£200 + VAT). The in-person survey and quotation are free.
For the full picture, including the TA6 form, the RICS management categories and our step-by-step timeline, see our selling or buying a house page.
If you are selling
- Get the plant identified and the extent surveyed early. It is easier before a buyer's survey finds it
- Start treatment or excavation as soon as practical, so there is a plan in place
- Keep every report, plan and certificate together to pass to your solicitor
- Do not try to hide it or dig it out quickly before a viewing. That can spread it and cause bigger problems
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If you are buying
- Ask the seller for the survey report, management plan and guarantee
- Check the guarantee covers the area concerned and how long it runs
- Ask your lender what they need before you exchange
- Take advice from your solicitor and surveyor on your specific case
Knotweed next door
If knotweed is on a neighbouring property near your boundary, it can still affect a sale. Document it, talk to your neighbour and get advice. A boundary treatment plan or root barrier may be part of the solution. See treatment vs excavation for how it is dealt with, and our Japanese knotweed service page.
Frequently asked questions
Can I get a mortgage on a house with Japanese knotweed?
Often, yes, but it depends on the lender. Many want to see a professional management plan and a guarantee. Check with your lender or broker.
Do I have to declare knotweed when selling?
Sellers in England and Wales are usually asked about it on the TA6 Property Information Form. Answer honestly and take advice from your solicitor.
What guarantee do you provide?
A minimum 5-year guarantee included on every job, available for up to 20 years, with a guarantee certificate and a management plan.
Do you provide reports for a property sale?
Yes. Formal CSJK (Certified Surveyor of Japanese Knotweed) survey reports for property sales, mortgages, insurance or legal needs are £240 (£200 + VAT). The in-person survey and quotation are free.
Related articles
- How to identify Japanese knotweed, season by season
- Japanese knotweed: herbicide treatment vs excavation
- Your neighbour's bamboo is coming into your garden: what can you do?
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