If Japanese knotweed is holding up your sale, the fix is usually a costed treatment plan and an insurance-backed guarantee, which is what a buyer's lender needs to proceed. A stalled sale rarely means the house is unsellable; it means the buyer and lender want the risk managed. Our guide to selling a house with knotweed sets out the disclosure duty, and this page focuses on getting a stuck transaction moving again.
Why is knotweed holding up my sale?
Knotweed is holding up your sale because a mortgage valuer has flagged it and the buyer's lender wants evidence the risk is managed before lending, not because the plant makes the property unsellable. The lender's concern is future cost and spread, which a professional plan and guarantee address. Once those are in place, most lenders proceed, so the hold-up is a document gap rather than a dead end. Arranging a survey and a costed plan is usually what turns a stalled sale back into a live one.
What gets a buyer and lender moving?
What gets a buyer and lender moving is a survey confirming the stand, a professional treatment plan, and an insurance-backed guarantee that funds further treatment if the knotweed returns, backed by an insurer so it stands even if the contractor stops trading. This package transfers the future risk away from the property, which is exactly what the lender needs. Audited Property Care Association members issue guarantees, typically for 10 years, that lenders accept, and it is the guarantee, more than the treatment itself, that unblocks the sale.
Does the knotweed have to be gone before I sell?
The knotweed does not have to be gone before you sell, because a costed plan and a lender-accepted guarantee are normally enough to proceed, with the treatment continuing after completion. A herbicide programme runs across 3 to 5 seasons, so requiring it to finish first would stall most sales unnecessarily. The buyer inherits the plan and guarantee. Where a buyer or their lender wants the ground clear immediately, excavation gives a same-week clearance, but for most sales the plan and guarantee are sufficient.
How quickly can it be sorted?
A survey and a costed plan can usually be produced within a week or two, which is often all a lender needs to proceed even though the treatment itself runs over several seasons. That speed is why a knotweed hold-up need not collapse a chain: the documents that unblock the sale come quickly, while the treatment happens in the background. Getting the survey booked promptly is the single most useful step when a sale is stuck, because everything the buyer and lender need follows from it.
Common questions
- Can I sell a house with untreated knotweed?
- You can, but most buyers and their lenders will want at least a costed plan and a guarantee in place. Selling with nothing in place usually means a lower price or a cash buyer, so a plan is generally worth arranging.
- Will I have to drop my price?
- Not necessarily. A treatment plan and guarantee reduce the discount a buyer expects, because the risk is managed. Where you offer no plan, a buyer will price in the cost of dealing with it themselves.
- Do I have to tell buyers about the knotweed?
- Yes. TA6 question 7.8 requires you to disclose whether the property is or has been affected, and a false answer can found a misrepresentation claim after completion. A survey supports an honest answer.