Despite the warnings that Japanese knotweed can become a serious threat to your property, a new report by the University of Leeds and engineering firm Aecom has now suggested it may not be as harmful as it has been believed to be.
Buy-to-let investors have continuously been warned about the issues it could cause, however, despite this, there are a number of landlords who cannot identify the plant.
It can result in rejections from mortgage lenders if left unchecked, with many requiring evidence of a planned treatment programme to remove it. However, with such research emerging stating that the plant is less of a threat than we believe it to be, could this be about to change?
They looked at evidence from previous research literature and assessed 68 residential properties at which Japanese knotweed had been found. Data was also collected from the removal of the plant by excavation from 81 additional sites.
Dr Mark Fennell, Principal Ecologist at AECOM, who led the study, said: “Our research sought to broaden existing knowledge about the risk to buildings of Japanese knotweed compared to other plants.
“We found nothing to suggest that Japanese knotweed causes significant damage to buildings – even when it is growing in close proximity – and certainly no more damage than other species that are not subject to such strict lending policies.”
Co-author Dr Karen Bacon, from the University of Leeds’ School of Geography, said: “The negative impact of Japanese knotweed on such factors as biodiversity and flooding risks remains a cause for concern.
“But this plant poses less of a risk to buildings and other structures than many woody species, particularly trees.
“Japanese knotweed is capable of damaging built structures, but where this occurs, it is usually because an existing weakness or defect has been exacerbated.”
Professor Max Wade, Technical Director of Ecology at AECOM, and co-author of the paper, said: “We hope our research will inform discussions around the advice currently offered about Japanese knotweed by providing more information about the reality of its impact on built structures.”
With the plant having caused financial issues for many homeowners, it may be good news if it becomes generally determined that knotweed is not as much of a threat as we originally imagined. It certainly could ease the financial burden for those attempting buy and sell properties afflicted by the weed.
The full report can be viewed on the University of Leeds website.
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