Japanese Knotweed is an invasive plant species that first reached the UK in 1850. 170 years later it’s still wreaking havoc for UK homeowners.
The strong root system can grow through brick, which can cause huge damages to property and deter mortgage lenders from lending. This can cause problems when you come to sell your house.
But can you even sell a house with Japanese Knotweed?
Yes, it is possible to sell a house with Japanese Knotweed. However, properties with Japanese Knotweed usually take longer to sell, will achieve a lower price, and sales are more likely to fall through. You’re required by law to declare Knotweed when selling your house, so there’s no skirting the issue either.
Although sales are more difficult and there are obligations you must meet, there are things you can do to stack the odds in your favour.
1. Quick Recap: What is Japanese Knotweed?
According to the UK's Environment Agency, Japanese Knotweed is "indisputably the UK’s most aggressive, destructive and invasive plant".
Here are the basics, and why Japanese Knotweed affects you as a home seller:
- Japanese Knotweed is an invasive plant species.
- It’s an aggressive weed with an extremely strong root system.
- The roots grow quickly, and are so strong they can grow through brick.
- This can cause massive problems to building foundations, which can result in huge damages.
- Mortgage lenders won’t lend on a property with Japanese knotweed because of this.
1.1. How common is Japanese Knotweed?
Unfortunately Japanese Knotweed is becoming more common.
There is now one Japanese Knotweed infestation for every 10 square kilometers in the UK. Based on the size of the UK, this means there are over 25,000 Japanese Knotweed infestations in the UK.
Infestations are not spread out evenly, so you may be more or less likely to have one depending on where you live. This map shows where infestations are concentrated.
1.2. How do you identify Japanese Knotweed?
Fortunately, Japanese Knotweed is quite a distinctive plant making it relatively straightforward to identify. There are also free AI-driven tools you can use that can confirm an identification in seconds.
Read our full article here for more:
2. Why are properties with Japanese Knotweed hard to sell?
While it is possible to sell a house with Japanese Knotweed, it's more difficult. Properties with Japanese Knotweed will typically:
- Take longer to sell,
- Achieve a lower price,
- And sales are more likely to fall through.
Why is this?
Because Japanese Knotweed can grow through brick it can cause serious structural issues with a property. This can even result in subsidence.
Because of these risks mortgage lenders will not lend on a property with Japanese Knotweed. This has two main consequences:
- You have fewer potential buyers when selling. This mean it takes longer to find your buyer. Less competition between buyers also results in a lower price.
- The remaining buyers will be cash buyers, who tend to expect a discount when purchasing.
Treating Knotweed before selling can help mitigate these issues though.
2.1. Should you treat Japanese Knotweed before selling?
Treating Japanese knotweed before selling your house is a viable option. Although there’s a substantial up-front investment and it takes some time, it may result in a higher sale price overall.
Removing Japanese Knotweed is costly and time-consuming though. You’ll need a specialist company to perform the removal. This typically costs between £2,000-£5,000.
But even then, successful removal is not a certainty. Your property will need regular treatment over 2-3 years until it’s completely eradicated.
Treatment Plan Guarantee
Knotweed Removal companies will give you a guarantee once you’ve put the treatment plan in place. Some mortgage lenders do accept this guarantee, and will be happy to lend on the property again. If this is the case, you may be able to sell to mortgage buyers.
There are still a couple of potential issues with this though.
First of all, even if lenders are ok with it buyers may still be put off.
Secondly, for many homeowners the cost of treatment may not be an option, or you may simply want to sell your house more quickly and move on sooner.
So, whether you’re proceeding with or without a treatment plan, how do you sell your house with Japanese Knotweed?
3. Selling a house with Japanese Knotweed
If you decide to sell a house with Japanese Knotweed there are two main things you need to be aware of.
- You’ll need to disclose it (more on this below)
- How you decide to sell is an important decision.
3.1. Disclosing Japanese Knotweed when selling your house
You must disclose Japanese Knotweed when selling your home.
There are two standard questionnaires that every homeowner must fill out when they come to sell their home:
- The Property Information Form (TA6)
- The Fittings and Contents (TA10) Form
The forms are designed and updated by the Law Society. The questions in them must be answered truthfully by the seller in order to avoid any legal repercussions in the future.
Japanese Knotweed didn't always feature in these forms. This meant that before 2013 you didn't need to disclose Japanese Knotweed. However, their form was updated in 2013 to include a question about Japanese Knotweed. The wording was refined further when they introduced the 4th edition in February 2020.
The exact wording from the latest version is as follows:
Because it's mandatory to disclose Japanese Knotweed once you've agreed a sale, you should also disclose it to your estate agent at the very start of the process. Otherwise you'll just waste time with buyers who aren't comfortable (or are unable) to proceed with the purchase.
Surveyors check for Japanese Knotweed too
If you have Japanese Knotweed you should absolutely disclose it. Legal repercussions in the future can be serious if you’ve knowingly withheld information about it.
Even if you decide to try and “get away with it” – which you really shouldn’t – you’ll likely still run into problems. This is because surveyors check for Japanese Knotweed. The leaves and stems are very distinctive, and any attempts to “cut back” knotweed are usually obvious. It's possible to get a survey on an auction property too.
If you have a problem with Japanese Knotweed, confront it. Don’t try and brush it under the carpet. If you try and hide the issue you’ll still struggle to sell, and may face serious consequences in the future.
3.2. What’s the best way to sell a house with Japanese Knotweed?
Once you’ve decided to sell and are prepared to declare the Japanese Knotweed, you need to decide how to sell.
You have three main options:
- Sell via estate agent
- Sell via an auction
- Sell to a house buying company.
The right choice for you is going to depend on two things:
- Have you put a treatment plan in place?
- Do you want the highest price, or a quicker sale?
3.3. Selling via an estate agent
If you’ve put a treatment plan in place and are hoping to get the best price possible, then you should try selling your property through an estate agent first. It can still be a difficult process though.
In theory, having a treatment plan in place should make the property mortgageable again. This is good because mortgage buyers pay the highest prices. But it isn’t always the case; many lenders still won’t want to lend.
Even if there are lenders, buyers themselves may still be put off. After all, the Knotweed may have already some damage that hasn’t yet been identified. This can lead to costly repairs later on.
The knotweed may still take several years to be completely eradicated as well, even after treatment has begun.
So although you may get a good price by selling through the estate agent it can still be a rocky journey:
- It’ll likely take longer to sell,
- The agreed price will be less,
- Sales will be more likely to fall through.
If you want to avoid this more drawn-out sale, auction may be a good option for you.
3.4. Selling by auction
Selling a house with Japanese Knotweed via an auction can be a good choice for three main reasons:
- Auctioneer experience levels. Auctioneers are likely to be more familiar with Japanese Knotweed properties than estate agents. This can help get the right types of buyers competing against each other for your property.
- Buyer experience levels. Buyers at auction tend to be more experienced too. Many will be familiar with Japanese Knotweed and will know how to proceed. They also tend to be cash buyers, so there are no issues for you with mortgage lenders.
- Binding sales. Because auction buyers must pay a hefty deposit when they win the auction, very few sales fall through. (Less than 1%).
Read more about the types of properties that are suitable for auction, and why auction can be a good choice for “problem properties”.
You should typically expect to sell your property for between 80-90% of its market value when selling via auction with Japanese Knotweed. The whole process can take around 8-12 weeks.
Bear in mind when selling by auction that a sale is not guaranteed. According to data from EIG, the industry standard for property auction information, approximately 78% of properties that go to auction sell successfully.
3.5. Selling to a house buying company
If 8-12 weeks is still a little too long and you’re looking for a faster, more certain sale, then selling to a genuine house-buying company can be an option.
Professional house buying companies typically pay around 80% of the market value for properties. However, remember that Japanese Knotweed is affecting the market value of the property.
As an example, if the Knotweed is knocking around 10% off the value of your property, a house buying company will offer you 80% of that. This effectively gives you a “double whammy” on the price you end up getting, and so you should only use a house buying company as a last resort.
Although it’s a hefty compromise on price, they can have the completion done in as little as 2 weeks. Our partner company, Yes Homebuyers, offers this fast house sale service and you can learn more about it on their website. Yes Homebuyers are registered with the Property Ombudsman and are members of the National Association of Property Buyers.
In short, although it is possible to sell a house with Japanese Knotweed it’s going to be more difficult.
If you can afford to put a treatment plan in place and have time to wait, you’ll get the highest price this way. You should use a reputable Knotweed removal company, and once initial treatments have been done you can begin selling with an estate agent.
Although this will take longer, you’ll get the highest price.
If you need a speedier option then the fastest way is selling directly to a genuine house-buying company. The downside is that you’ll end up with a much lower price.
Selling by auction can be a good compromise between the two. You’ll get a higher price than selling to a house buying company, but it’ll be a much faster sale than going through an estate agent.
It really depends on your preferences, how quickly you’re looking to move, and whether or not you can the spare funds to put a treatment plan in place.
By Matthew Cooper, Founder of Home Selling Expert