RICS Japanese knotweed categories A to D

At SE Knotweed, we record a knotweed case against the RICS 2022 management categories A to D, which grade the risk to the property and its neighbours using a 3 metre zone rather than the older 7 metre one.

What are the RICS Japanese knotweed categories?

At SE Knotweed, we record every case against the RICS management categories A to D, the assessment framework the RICS Professional Standard 2022 introduced to grade Japanese knotweed by the management action a property needs rather than by distance alone.

The category tells a mortgage valuer and a solicitor how serious the case is and what has to happen before a sale or a loan can proceed. Our survey records the band for your site and explains what it means.

What changed in the RICS 2022 standard?

The RICS Professional Standard 2022, in force from 23 March 2022, replaced the older 2012 approach: it dropped the 7 metre zone in favour of a 3 metre zone and swapped the numbered risk categories 1 to 4 for the management categories A to D.

It also states that sound, modern foundations are unlikely to suffer structural damage from knotweed, which moved the focus from alarm to management. Valuers and lenders now read cases in this language.

What does each management category A to D mean?

The four RICS management categories run from A, the most serious, to D, where the source sits off the property. Category A means visible, material damage to a structure; B means no such damage but remediation and an insurance-backed guarantee are advised; C means the stand can be managed with limited impact; and D means the knotweed originates on adjoining land within 3 metres of the boundary.

RICS 2022 management categories, indicative
CategoryWhat it indicatesTypical implication
AVisible, material damage to the property or a significant structure such as an outbuilding or boundary wallThe most serious band; treatment and often repair are needed before lending
BWithin the 3 metre zone with no visible structural damageA management plan and an insurance-backed guarantee are advised; the common mortgage band
CPresent but with limited impact on this property; the stand can be managedUsually manageable without holding up a sale once a plan is in place
DThe knotweed originates on adjoining land, within 3 metres of the boundaryYour report records the off-site source; your side is planned and the neighbour position is separate

How does the category affect a mortgage valuation?

The RICS category shapes a mortgage valuation because it tells the lender how much management the property needs: a Category B or C case usually proceeds once a plan and an insurance-backed guarantee are in place, while a Category A case may need repair as well as treatment before a valuer will lend.

The category is not an automatic refusal. Our knotweed and mortgages pillar explains how lenders treat each band and how a costed plan moves the case forward.

Does a category mean my foundations are damaged?

A category does not mean your foundations are damaged: the RICS 2022 standard states that sound, modern foundations are unlikely to suffer structural damage from knotweed, which exploits existing gaps, drains and cracks rather than breaking sound concrete.

Category A is reserved for cases where damage is actually visible, often to a lightweight structure like an outbuilding, a path or a boundary wall. The survey records what is genuinely present rather than assuming the worst.

What replaced the old 1 to 4 risk categories?

The management categories A to D replaced the numbered risk categories 1 to 4 that the 2012 framework used, shifting the assessment from a risk score to the action a property needs. The 3 metre zone also replaced the older 7 metre one.

An older report may still refer to the 1 to 4 bands, so if you hold one from before 2022 it is worth a fresh survey to record the case in the language a current valuer and lender expect.

How is my category decided at survey?

Your category is decided at survey by measuring the distance from the stand to the dwelling, outbuildings and the boundary, checking for visible damage to any structure, and recording whether the source is on your land or an adjoining plot.

We photograph the stand, map it against the 3 metre zone and set the finding out in the report with the reasons. Book a survey and we will record and explain your category.

What can I do to move the sale forward?

To move a sale forward after a category is recorded, the step is to put a management plan and an insurance-backed guarantee in place, which is what lets a lender proceed even while treatment continues.

We produce the management plan from the survey and set out the guarantee term, so your solicitor can answer the buyer's enquiries and the valuer can release the loan.

Common questions

Is Category A the worst?
Yes. Category A is the most serious band, reserved for visible, material damage to the property or a significant structure. Most domestic cases fall into B or C, which are manageable with a plan.
Can my category improve after treatment?
A completed treatment programme with monitoring and no regrowth changes how a valuer sees the property, and the insurance-backed guarantee is what carries that confidence to a lender.
Do all surveyors use the RICS categories?
Accredited knotweed surveyors and RICS valuers work to the 2022 categories, which is why a report in this format is the one a lender expects. An informal opinion that records no category rarely satisfies a valuer.
Does the 3 metre zone include next door's garden?
Yes. The 3 metre zone is measured from the stand in every direction, so knotweed within 3 metres on an adjoining property is recorded, which is what a Category D finding reflects.

Book a survey and get a costed plan

Tell us the address and what a surveyor flagged. We confirm the plant, record the RICS category and set out the figures.

Book a survey
Call 01924 944600