Getting a mortgage
A house or flat with evidence of Japanese knotweed can potentially be a real issue. Before we talk a little about this it is important to understand that a prospective lender will need to know how close or far the Japanese knotweed is from the dwelling.
The Royal Institute of Chartered Surveyors (RICS) puts the risk into 4 categories depending on its proximity to the boundary or dwelling. It is these categories that could define whether a lender will consider lending and indeed whether the lender would require a treatment program to be in place.
RICS categories
The Royal Institute of Chartered Surveyors (RICS) provides some standard information on the subject of Japanese Knotweed and puts the risk into 4 categories depending on its proximity to the boundary or dwelling.
When visible damage has been caused lenders will require an inspection by a suitably qualified specialist who is a member of a recognised trade body and the completion of any recommended works under a Japanese Knotweed Management Plan, with the benefit of an insurance-backed guarantee. The value of a property is likely to be affected when an infestation is assessed at this category. Valuers should take account of all relevant factors, including current market conditions, when considering the impact of an infestation on value at this category.
Most lenders will not consider lending where visible damage has been caused.
When Japanese knotweed is likely to prevent use of or restrict access to amenity space, it is anticipated that most lenders will require an inspection by a remediation specialist who is a member of a recognised trade body and the completion of any recommended works under a Japanese Knotweed Management Plan, with the benefit of an insurance-backed guarantee. The value of a property may be affected when an infestation is assessed at this category. Valuers should take account of all relevant factors, including current market conditions, when considering the impact of an infestation on value at this category.
An assessment at this level indicates that an infestation is not causing damage to significant structures within a site and not likely to prevent use of or restrict access to amenity space. It can therefore be considered as having a low impact on the property.
The lender may recommend an inspection by a remediation specialist who is a member of a recognised trade body so the property owner can be advised about future management and control. This is particularly relevant if the growth is within 3m of a boundary. There may be some impact on the value of a property when an infestation is at this level, but this will usually be modest and more likely to be a reflection of the cost of any remediation rather than any direct effect on the use of the property itself. Valuers should take account of all relevant factors, including current market conditions, when considering the impact of an infestation on value at this category.
An assessment at this level indicates that an infestation has not been seen within the subject site.
The situation should be reported to the lender or client, but remedial action on land beyond the subject property is not within the control of the property owner. Proximity to the boundary means there is a possibility that there may be future spread from the off-site infestation onto the subject site. The likelihood of any possible spread will largely depend on the extent of the adjoining infestation. If an infestation is on neighbouring land there may be relatively little prospect of spread but if the adjoining infestation is extensive, the probability of spread may be greater.
In some circumstances, it may be appropriate for advice to be sought from a remediation specialist about the merit of taking defensive measures against possible future encroachment. In most cases, there is likely to be limited impact on value unless a severe adjoining infestation makes expensive defensive measures desirable. In certain situations, there may possibly be implications for remediation and, rarely, perhaps even potential legal action. This could increase the impact on value, but only in exceptional circumstances would an infestation at this category be expected to be made the subject of a mortgage advance condition.
Irrespective of the extent of an adjoining infestation, and if discussion or negotiation are not successful, there is no practical way for a property owner to impose remedial measures on an adjoining owner without taking legal action of some sort. Consequently, it is not appropriate for lenders to require remediation of an infestation on adjoining land as a condition of a mortgage advance because it is effectively beyond the control of the mortgagee/property owner to impose this. Even when an adjoining owner is willing to undertake remediation, it may not be possible to ensure that work is carried out by an approved contractor or with the benefit of an insurance- backed guarantee (typical lender requirements). Additionally, remediation undertaken by statutory bodies or local authorities may be carried out by their own contractors, which are unlikely to meet this requirement in any event.
Can You Get a Mortgage with Japanese Knotweed? Here's What Lenders Say
When it comes to getting a mortgage on a property affected by Japanese knotweed, lenders have mixed views. Their decisions often depend on how severe the infestation is, and whether a treatment plan or Japanese knotweed survey is in place.
Here’s how most lenders respond based on the
RICS Japanese Knotweed Categories:
RICS Category A – Visible Damage
Many lenders will not lend on Category A properties, especially where visible damage is present.
If a lender does consider it, they usually require:
A Japanese knotweed survey
A fully paid treatment plan
Some lenders may retain part of the mortgage funds until proof of the treatment is provided.
Others might rely on the valuer’s comments, along with confirmation of treatment.
RICS Category B – Impact on Use or Access
Category B typically involves knotweed that affects the use or access to gardens or outdoor areas.
Most lenders treat it similarly to Category A.
A few lenders might decline Category A cases but still consider lending on Category B.
RICS Category C – No Structural Damage
This category opens more mortgage options.
Japanese knotweed is present but not damaging any significant structures.
Lenders will often still want to see a knotweed survey.
RICS Category D – Nearby Infestation
Knotweed is not on the property itself, but is present on neighbouring land.
In many cases, this doesn't cause an issue.
However, if the nearby infestation is severe, some lenders might still refuse to lend due to the risk of spread.
What Else Do Lenders Require?
Some lenders ask for a 5-year insurance-backed guarantee, while others require 10 years.
Others may simply rely on the valuer’s assessment, especially in borderline cases.
How Japanese Knotweed Mortgages Can Help
Knowing which mortgage lender to approach is not always straightforward. That’s where we come in.
At Japanese Knotweed Mortgages, we speak directly with lenders, often consulting their Business Development Managers or underwriters to get an indicative decision based on real experience with similar cases.
Working with a mortgage adviser who understands:
The nuances of Japanese knotweed cases
The different lender policies
And how to package your application effectively
...can make all the difference.
to find out how we can help you secure a mortgage — even with Japanese knotweed on or near your property.