Japanese Knotweed? Knot a problem

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For years residential property owners with Japanese knotweed growing close by have been blighted by the plant and the detrimental impact it has on the value of their property. There is, however, now some light at the end of the tunnel. The Royal Institute of Chartered Surveyors (“the RICS”) has published new guidance in light of “improved understanding” about the impact of the weed on residential properties, scrapping the “seven-metre rule” that valuers and surveyors (and therefore lenders) use to determine whether Japanese knotweed is a threat to a property.

Why is the presence of Japanese knotweed a problem?

Japanese knotweed is an invasive and fast-growing plant that can cause severe damage to property and as a consequence can have a serious detrimental effect on the value and saleability of a property. Getting rid of it is a lengthy, disruptive and expensive process and necessitates the involvement of specialist companies who can deal with the proper disposal of the plant. Criminal penalties apply to anyone who fails to dispose of Japanese knotweed in the proper way or allows it to grow in the wild.

The presence of the plant not only has a detrimental effect on a property’s value, but can also lead to expensive legal disputes between neighbours where it crosses the boundaries and causes an actionable nuisance (the RICS guidance lays the blame for this partly at the feet of “no win no fee” organisations taking advantage of the cautious approach previously adopted by the RICS and lenders). Furthermore, a property owner’s “failure to act” in relation to Japanese knotweed could also contravene the Anti-Social Behaviour, Crime and Policing Act 2014 and lead to the issue of Community Protection Notices by the police or local authority and ultimately fines for failing to control the spread of the plant.

What is the “seven-metre” rule?

Valuers and surveyors have to date relied upon the (overly) simplistic “seven-metre rule”.  In short, if there is Japanese knotweed growing within seven metres of a property they deem that property to be at risk of severe damage from the plant.

As a consequence lenders have previously been very reluctant to lend on properties where the plant grows (or has been known to grow) within seven metres of it, regardless of whether it has actually caused any damage or had any impact on the building itself. This has made it very difficult for property owners to sell or re-mortgage their property, even where there is no evidence of the plant having caused actual damage. It has been a particular problem for owners of flats, where the management of the plant growing within the vicinity of the block is outside of their control, but the value and saleability of all of the flats within the building is affected by the freeholder or management company’s failure to take appropriate steps to manage the growth.

In a 2019 report by the House of Commons Science and Technology Committee, the approach taken by mortgage lenders in relation to Japanese knotweed was described as “over-cautious” and as having a “chilling” impact on the sale of a property. The report also referred to the “seven-metre rule” as a “blunt instrument that did not reflect the latest scientific evidence” and called for a more nuanced and evidence-based approach to reflect the actual potential risk the presence of the plant poses to a particular property. It is partly this report that has led to the RICS reflecting upon their previous guidance.

What does the new RICS guidance say?

The new guidance acknowledges that the “seven-metre rule” focuses on what has been demonstrated to be an overstated risk of Japanese knotweed to buildings, rather than its “sometime-serious” impact on amenity. The impact on the market, the report states, was also increasingly influenced by “exaggerated media reporting, resulting in an adverse public perception out of all proportion to the actual problem” (perhaps an attempt by the RICS to deflect some of the blame from its previous guidance). The new guidance is intended to provide clarity and help to “rebalance perceptions”.

The RICS cites research that has demonstrated that Japanese knotweed poses little or no risk of structural damage to robust buildings with substantial foundations (e.g. dwellings), as opposed to large strands or growths of the plant which, if left uncontrolled, can cause damage to lightweight structures with shallow foundations (e.g. conservatories, garages, paths, drains or boundary walls).

The guidance introduces a new structured assessment framework for valuers and surveyors, with the focus on the “objective categorisation of any given infestation” of Japanese knotweed.  There is a shift towards encouraging valuers and surveyors (and therefore lenders) to focus on reporting on outcomes related to the proper management and control of Japanese knotweed (not necessarily total eradication) rather than emphasising the theoretical risk to buildings.  This in turn should hopefully lead to lenders taking a less restrictive approach to lending on properties where Japanese knotweed is or has been growing nearby. The impact of the weed on amenity space (as opposed to the structure of a building) will still be a relevant consideration for a valuation e.g. if the plant is growing in the garden of a small plot, this is likely to have a greater impact on the value of the property than if it is an established area of planting on a large plot or estate.

What about situations other than valuations?

The guidance does recognise that the assessment of Japanese knotweed is not only carried out in the context of valuations but in other circumstances too. For example, it provides that when assessing damage to structures (relevant in circumstances such as legal disputes over the cause of damage to a property) surveyors should differentiate between cases where damage has actually been caused by the growth (e.g. where the root mass has pushed over a garden wall), from those where growth is simply present in areas that are already in a poor condition, irrespective of the Japanese knotweed. This recognises the fact that the plant will grow in the line of least resistance and may grow through pre-existing cracks in brickwork in search of light and water. The report also introduces new guidance for surveyors reporting and advising on infestations on neighbouring land that may lead to an actionable nuisance claim by one neighbour against the other.

So this is good news…?

Absolutely. It remains to be seen how lenders will react to the new guidance and whether they will be more flexible when it comes to lending on properties where there is Japanese knotweed growth in the vicinity, but the RICS guidance is clear that the risk of severe damage to robust structures is minimal and that valuation reports should focus on the actual risk the infestation poses and how this can be managed. Hopefully this will in turn lead to lenders to taking better informed decision and considering the actual risk factors on a case by case basis rather than simply a “computer says no” approach.

This article is for general purpose and guidance only and does not constitute legal advice. Specific legal advice should be taken before acting on any of the topics covered. No part of this article may be used, reproduced, stored or transmitted in any form, or by any means without the prior permission of Brecher LLP.