Japanese Knotweed and Mortgage Risks: A Case in Waterlooville, Hampshire

One of the first properties I assessed with a potential Japanese Knotweed problem was a new-build home in Waterlooville, Hampshire. Knotweed was found along the northern boundary and in the neighbouring school field, covering around 100 square metres.

A specialist report confirmed the school site was under treatment, but signs of regrowth and dormant crowns raised concerns for the mortgage lender’s valuer, who needed assurance about long-term risk. To progress, I liaised with the estate agent, builder, school, treatment company and solicitors. The valuer required written evidence that the school’s land would remain under a continuing knotweed management plan to prevent spread back into the garden and towards the house.

Even with a 10-year Japanese Knotweed guarantee, protection is limited if adjoining land is untreated. Once a plan ends, knotweed can quickly re-establish from neighbouring sites.

This case involved significant back-and-forth, but by understanding lender requirements, assessing the risk early, and coordinating with all parties, the purchase concluded and my clients moved in. Not all lenders would have approved, underlining why early identification and professional knotweed advice are vital in property transactions.