Selling a house with Japanese knotweed
You can sell a house with Japanese knotweed — but you must declare it on the TA6 form, and buyers and lenders will expect a professional management plan with an insurance-backed guarantee. Around a third of buyers walk away from affected homes and values dip ~5% (about £13,500), so a documented, guaranteed treatment plan is the key to a smooth sale.
Do I have to declare knotweed when selling?
Yes. The standard TA6 Property Information Form asks whether the property is or has been affected by Japanese knotweed. Answering incorrectly — even about a past, treated infestation — risks a misrepresentation claim after completion. Disclose it and provide your treatment plan and guarantee.
How to sell smoothly
Get a survey and management plan, arrange professional treatment with a 5–10 year insurance-backed guarantee, and keep all paperwork ready for the buyer's solicitor and lender. A guaranteed plan reassures buyers, keeps the property mortgageable, and protects your sale price.
Your selling timeline, step by step
Handled in the right order, knotweed needn't derail a sale. Start this before you market the property and the process barely touches your timeline:
- 1Get a professional survey
A PCA-accredited surveyor confirms it is knotweed, maps the infestation and checks its proximity to boundaries and structures. This becomes the evidence base for everything that follows.
- 2Commission a Knotweed Management Plan
A written 5–10 year plan setting out the treatment method, schedule and expected outcomes — exactly what a buyer's solicitor and lender will ask to see.
- 3Arrange treatment with an insurance-backed guarantee
Work begins under the plan. The transferable IBG is the single most important document for keeping the property mortgageable.
- 4Complete the TA6 form honestly
Declare current or historic knotweed and attach the plan and guarantee. Full disclosure protects you from a costly misrepresentation claim after completion.
- 5Share paperwork with the buyer's solicitor & lender
Provide the survey, plan and guarantee up front. Doing this early prevents mid-sale delays and last-minute price chipping.
- 6Guarantee transfers on completion
The IBG passes to the buyer, giving them and their lender long-term protection — and letting your sale complete on time.
You don't need to finish the whole programme before selling. As long as a plan and transferable guarantee are in place, most lenders will proceed — so getting a specialist in early is what protects your price.
