RICS Draft Guidance Note: Japanese knotweed and residential property, 1st edition

5 Reporting and recommendations

5.1 Reporting to lenders

The primary objective of the Management Category assessment process is to provide consistency across the residential property market so that all stakeholders can understand the significance of Japanese knotweed at or near any given property. Whatever the circumstances found on-site, the actions needed to achieve a satisfactory route through to mortgage finance should be equally apparent to valuers and surveyors, vendors and purchasers, lenders and remediation specialists.

When Japanese knotweed is identified, the Management Category assessment decision tree (see section 4.5) should be used to categorise the infestation at the relevant Management Category, which can then be reported to the lender in the usual way.

The notes beneath each of the Management Category assessments, supplemented by the accompanying notes at section 4.6, are largely self-explanatory and provide recommendations that most lenders will hopefully be willing to adopt in the furtherance of greater consistency in lending policies across the market.

Valuers reporting to lenders for mortgage purposes will understand, however, that each lender sets its own lending policies and they will need to be aware of any variations from the standard recommendations.

The valuation of properties affected by Japanese knotweed, and the factors affecting value, are covered specifically in section 7.

Note: It will be seen that the recommendations for management categories A and B are virtually identical, both recommending 'action' and anticipating mortgage retentions pending advice from a remediation specialist. The two categories have been separated to differentiate between instances where Japanese knotweed has visibly caused damage to a structure from those where it is adversely impacting on amenity. It is hoped that this separation will improve understanding of where the main issues arise and potentially facilitate refinement in lending policies as they respond to the new assessment process.

5.2 Reporting for other purposes

When Japanese knotweed is identified during an inspection being undertaken for purposes other than lending, the decision tree should be used to categorise the infestation at the relevant Management Category, which can then be reported to the client.

The depth and detail of reporting by RICS members acting for clients other than lenders will be determined by the agreed Terms and Conditions of Engagement. Using the Management Category assessment will assist in positioning advice to the client. Reports at level three would be expected to be more detailed than those at levels one and two.

Section 7 of this guidance note deals with the valuation of properties affected by Japanese knotweed but it also includes general observations about the impact of Japanese knotweed, which will assist those providing advice to clients even where a valuation is not required.

5.3 Properties affected by Japanese knotweed

Where Japanese knotweed is found at a property or if the surveyor has personal prior knowledge, or where no Japanese knotweed has been seen but it emerges through questioning, or from some other source such as solicitor's enquiries before contract, that there is previous knowledge of its presence, one of two responses are appropriate:

  • Where there is no satisfactory evidence to show that a properly planned Japanese knotweed programme is currently in hand or has been properly completed, further investigations by a recognised contractor should be recommended or
  • Where there is satisfactory evidence to show that Japanese knotweed is currently or has been subject to a recognised remediation strategy by a recognised contractor further investigation will not be required and a recommendation for the client or legal adviser to obtain and inspect the documentation should be included in the report.

When further investigation is required it should be carried out by an accredited member of a recognised trade body. To date there are two associations that provide this assurance, the Property Care Association (PCA) and the Invasive Non-Native Specialists Association (INNSA). The report and, if appropriate, a Japanese Knotweed Management Plan (JKMP) should be provided following the specialist inspection. Details of what the JKMP can be expected to include are specified in section 6.1 of this guidance note.

In cases where a residential practitioner is advised that remedial treatment is in hand or has been completed it will be a matter for the individual's professional judgement to decide what constitutes 'satisfactory evidence' but most professional JKMPs provide a warranty or guarantee. This provides assurance to the client that for a specified period, usually five or ten years, if any growth or re-growth occurs within the treatment zone the contractor will return and conduct further treatments as required. In some cases, there may also be a separate guarantee insurance policy (known as an insurance-backed guarantee) so that the guarantee remains valid even if the original contractor ceases to trade. Confirmation of an appropriate JKMP or a guarantee would normally be considered satisfactory evidence.

5.4 Neighbouring properties

Where Japanese knotweed is confined to the grounds of a single property, its management will normally be a straightforward process involving only two parties: the property owner and the contractor. However, where Japanese knotweed straddles the boundaries of more than one property the solution will not be so simple.

The most effective solution will be the treatment of the Japanese knotweed within the property boundary and any part connected to that infestation whether outside the boundary or not. A JKMP should advise of any neighbouring party's agreements, whether voluntary or legally imposed, and any additional contractual issues. These will be required to ensure a successful treatment programme.

In some residential areas property ownership can be complex and transient and establishing a joint remediation strategy in this situation will be challenging. In these cases, providing root barriers along the boundary may appear an attractive option to lenders who require a straightforward, time-limited solution. However, installing a root barrier may not be a viable or effective treatment for many domestic properties and alternative solutions may be required:

  • Deep excavations to depths required may be expensive, disruptive and could be legally challenging, as the owner's legal advisers consider matters relating to boundaries, party walls and general property rights.
  • Not all commentators agree that root barriers on their own are effective ways of preventing the spread of Japanese knotweed (see the Property Care Association Guidance Note: Root Barrier and Japanese Knotweed Remediation).

When an infestation is not present at a property but has been seen on neighbouring or nearby land and the RICS member is acting for reasons other than lending purposes it will be appropriate to report and advise on infestations seen beyond the distance of 3m from the boundary used by the Management Category assessment. This will depend on the specific circumstances, as well as the level of service being provided, but the RICS member should report the matter in a balanced way, which puts any risks into context.

Judgments in recent court cases have confirmed that Japanese knotweed is an actionable nuisance and neighbouring owners have been required to implement control and management measures to prevent spread of Japanese knotweed from their land onto that of neighbours (see Network Rail Infrastructure Limited v Stephen Williams and Robin Waistell [2018] EWCA Civ 1514 and Hardwicke (2018): Japanese knotweed nuisance in the light of Waistell and Smith v Line).

It is also worth noting that in 2014 a guidance note produced by the Home Office described how, under Section 57 of the Anti-Social Behaviour, Crime and Policing Act 2014, 'a failure to act' could be applied to Japanese knotweed (and other invasive species such as Himalayan balsam and giant hogweed), leading to the issue of Community Protection Notices by the police and/or local authorities. This has been successfully used by some local authorities (for example, by Bristol City Council in 2018 when a property owner was fined £18,000 for failing to control the spread of Japanese knotweed) but this remedy is not directly available to private homeowners.