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Japanese Knotweed Mortgage Problems

Homeowners can find the value of their properties severely decrease and their properties become hard to sell should they be affected by Japanese Knotweed as potential buyers are often unable to obtain a mortgage on a Japanese Knotweed infested property. But Knotweed does not always mean a mortgage is obtainable.

Should I buy a house with Japanese Knotweed?

Buying a house with Japanese Knotweed is perfectly fine providing that:

  1. There is evidence of Japanese Knotweed treatment plan with licensed removal experts
  2. There is a 10-year insurance backed guarantee from your professional treatment providers

Buying a property can be a stressful experience, and your dream move can quickly become a nightmare if Japanese Knotweed is discovered on the property. Removing Japanese Knotweed can be an expensive and lengthy process, and if you’re buying a property affected by it, the issue could last years and seriously affect the value of your property. This is why mortgage lenders have mixed approach to how it handles cases of Japanese Knotweed, as it can end up being very costly. It’s important to find out your mortgage lenders’ stance on Japanese Knotweed, as with a reliable treatment programme in place and a 10 year guarantee, there is no reason why Japanese Knotweed on the property should prevent your house sale or purchase.

Can I get a mortgage on a property with Japanese Knotweed?

You should be able to obtain a mortgage providing you know that:

  1. The presence of Knotweed could affect your house price and valuation of your property
  2. Lenders will be cautious to lend if Japanese Knotweed is found on your property or neighbouring property
  3. You will have to meet certain criteria depending on your lender and specific case

Who is responsible for clearing Japanese Knotweed?

If you are buying a house with Knotweed, you should ensure a professional company with an in-depth management plan and guarantee is in place. By allowing the seller to manage the Japanese Knotweed problem, it could lead to a quick, inadequate solution that may not satisfy lender requirements, or the problem returning.

If you are buying and Knotweed is found, it’s advised to seek professional guidance.

Do you have to declare Japanese Knotweed on the TA6 Property Information Form or report within surveys & valuations?

The Law Society TA6 Property Information Form was updated in February 2020 to put more pressure on sellers to declare whether or not their property is affected by Japanese Knotweed.  If it is not known, sellers should take necessary steps to find out. This may involve instructing a specialist company such as ourselves to carry out a survey at the property. 

Mortgage surveyors & valuers are trained to look out for signs of Japanese Knotweed so if you are not honest, or try to conceal this, it will most likely lead to your mortgage being declined after valuation, until a treatment programme has been implemented. We are also seeing cases where sellers are being pursued by solicitors for misrepresentation.  

It’s important to have a thorough survey conducted to ensure the presence of Knotweed is determined and prevent future Japanese Knotweed mortgage problems. Detecting it early on can help you to ensure there are measures put in place such as a treatment programme and insurance backed guarantees, so you can proceed with your house sale or purchase. 

Mortgage lenders’ attitude towards Japanese Knotweed

Mortgage lenders often require evidence of a suitable Japanese Knotweed treatment programme as a condition of lending if the plant is present on or near to a property. Lenders may retain some of the mortgage until the buyer can prove they’ve successfully eradicated the Knotweed. A 10-Year Insurance Backed Guarantee must also be in place upon completion. So this may affect the treatment plan chosen by the seller.

Lenders will handle cases of Japanese Knotweed differently according to their particular guidelines or may consider applications on a case-by-case basis, but you may need to commit to treat the Knotweed or begin initial treatment before getting a mortgage confirmed. 

Each lender’s view is different as there is no industry standard. However, a recognised standard through theRoyal Institution of Chartered Surveyors (RICS) may be used where they place the case into five categories depending on the level of severity.

Here are the stances of some of the UK’s biggest lenders on Japanese Knotweed mortgages.


Barclays demands an expert site assessment, and will not offer a mortgage until the Japanese Knotweed has been treated.

Nationwide Building Society

Nationwide Building Society says: “If Knotweed is prominent less than seven metres from the house we request a specialist report about eradication before deciding whether we can lend. Even if further away we require written confirmation from the borrower they are happy to proceed with a mortgage application despite presence of the plant.”


Santander expects professional Knotweed treatment before lending homeowners money. It also expects you to keep money aside for future treatments in order to keep the garden clear.

Need expert removal with a 10-Year Guarantee?

If your property is being purchased or sold, we offer our 10-Year Insurance Backed Guarantee. As soon as our team have successfully removed all traces of Japanese Knotweed from your land we can provide you with this guarantee.