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Guide to getting a mortgage with Japanese Knotweed

Japanese Knotweed giving you mortgage problems? Our mortgage advisors are here to help you secure the right product for your needs, whatever your circumstances.

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Japanese knotweed infestation is one of the most common problems affecting properties across the UK. It can affect not just the foundation or structural integrity of a property, but also the value of the property. 

The decrease in value depends on the extent of the infestation and the closeness of the spread to the property. According to a 2013 study by Nottingham Trent University, an existing Japanese knotweed infestation can reduce the value of a property by up to 15%. 

However, recent guidance from RICS states that Japanese knotweed poses little to no risks. Therefore, the chances of mortgage approval on properties infested with Japanese knotweed may increase. 

This comprehensive guide to Japanese knotweed mortgages will help you assess whether or not acquiring a mortgage on infested properties is possible. It will also help you understand the risks, policies, and consequences of getting a mortgage on such properties.

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What Areas Are Commonly Infested With Japanese Knotweed?

Since Japanese knotweed can tolerate various types of soil and moisture conditions, it can survive almost anywhere in the UK. In 2023, more than 50,000 cases were recorded!

To add, Japanese knotweed is mostly prevalent in areas like Nottingham, Glasgow, Bristol, and Rotherham. Apart from these, they are also common in the following locations:

  • London
  • Manchester
  • Newcastle
  • Birmingham
  • Liverpool
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How Can Japanese Knotweed Affect My Property?

First and foremost, it’s important to understand that Japanese knotweed affects buildings with compromised structures and old buildings the most. 

The Japanese knotweed spreads uncontrollably due to its aggressive and resilient nature. The root system can spread up to 7 metres deep!

In addition, the Japanese knotweed can grow up to 10 centimetres per day during its growing season. Just imagine how far it can expand in just days!

Aside from its exceptional capacity to grow and spread, Japanese knotweed is also very sturdy. As a result, it affects the walls of your homes and nearby buildings and can block underground structures like your drainage pipes.

Another reason why Japanese knotweed spreads so easily is that it grows even from tiny plant fragments, as well as from pre-existing holes and cracks. Did you know a new plant can emerge from a 2.5-centimetre root fragment? 

Lastly, its non-native nature means no plant species can compete with its growth. Therefore, it displaces other plants and threatens wildlife as well.

Another reason why Japanese knotweed spreads so easily is that it grows even from tiny plant fragments, as well as from pre-existing holes and cracks. Did you know a new plant can emerge from a 2.5-centimetre root fragment? 

Lastly, its non-native nature means no plant species can compete with its growth. Therefore, it displaces other plants and threatens wildlife as well.

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What is the impact of Japanese Knotweed on my home?

Did you know that the presence of Japanese knotweed, even a few metres away from your home, could mean that the roots are already underneath it? This is because its root system can regenerate and spread so quickly.

In no time, the roots will eventually protrude from any weak joints or openings in your walls or floors and start invading the inside of your house. 

Moreover, Japanese knotweed can damage concrete and even asphalt. This is why roots can damage even pavements. 

The Japanese knotweed’s rapid growth rate can also result in the following:

  • Break or lift pavements and drives.
  • Stems breaking from bricked walls.
  • Roots clogging or breaking pipes.
  • Destabilise the foundation of your home by breaking through existing cracks or gaps.
  • Damage to other structures like gardens, patios, fences, and even greenhouses.

If you’re in the UK, it’ll be helpful to know the usual hotspots where Japanese knotweed are known to invade.

What Is Japanese Knotweed?

If you’re eyeing a property, you must watch for signs of Japanese knotweed infestation. While this pernicious plant may look harmless, it can prohibit you from obtaining a mortgage.

Japanese knotweed, or Reynoutria japonica, is an invasive, non-native knotweed species that are an increasing problem all over the UK. 

This plant is aggressive, especially when left untreated. As a result, the Japanese knotweed causes massive damage to homes and even underground structures.

Originally brought to the country as an ornamental plant from Eastern Asia, the Japanese knotweed eventually became a significant problem. 

This notorious weed spreads rapidly through its seeds or fragments of its stems and root system (called rhizomes). Further, this plant can grow up to 3 metres high.

Meanwhile, the identification of Japanese knotweed can be confusing. Often, it can be mistaken as dogwood or other less invasive shrubs. So, to properly identify Japanese knotweed, here are some key features to look out for:

  • Pointy, heart-shaped leaves that are light to bright green and sometimes sprinkled with red to purple spots.
  • A distinct zigzag pattern on stems or leaves.
  • Small, creamy-white coloured flowers that cluster in panicles (can grow up to 10 cm long).
  • Roots that are dark brown coloured on the outside, but orange on the inside.
  • Hollow shoots resembling bamboo can grow up to 3 metres high.
  • New shoots are reddish brown coloured in spring and green during summer.

Early identification and immediate treatment through a specialist knotweed removal service are required to prevent an out-of-control invasion. It’s best to seek expert help to exterminate this stubborn weed fully.

Note also that the extent of the infestation can affect your property and other structures like electricity cables, drainage pipes, and more.

Frequently Asked Questions

How Is Japanese Knotweed Infestation Treated?

Getting rid of Japanese knotweed may include physical removal or treatment with chemicals. Sometimes, it’s a combination of both. 

Apart from that, removing surface growth alone doesn’t guarantee that Japanese knotweed will stop growing. This plant can go dormant and reemerge again after a few years.

Even the use of herbicides or weedkillers isn’t sufficient to hamper the growth of Japanese knotweed. Moreover, treatment can last as long as 3 years, depending on the extent of the infestation. And aside from the lengthy treatment process, it can be quite costly, too. 

Proper disposal of Japanese knotweed is a tedious process too. If improperly disposed of, Japanese knotweed can spread into the wild, which may subject you to criminal charges. 

On that account, the UK government suggests that treatment is better done by certified experts and using only approved herbicides. 

In conclusion, the best choice would be hiring PCA-certified knotweed specialists to get the job done. It’s also a plus if the knotweed specialist offers warranties to ensure that eradication will be effective until the next ten years.

Yes, acquiring a property with a Japanese knotweed problem is still possible. While Japanese knotweed can affect the approval of your mortgage, each mortgage lender will have different policies based on the extent of the infestation.

Thus, knotweed infestation that’s beyond the property’s boundary may not be a major issue. However, having one near the property may reduce your chances for mortgage approval.

As previously mentioned, Japanese knotweed can lie dormant for years. However, it may reemerge once the soil is dug through. This is one of the reasons why mortgage lenders are meticulous when it comes to surveying knotweed-infested properties.

The RICS (Royal Institution of Chartered Surveyors) released a new guidance stating that buildings with substantial foundations are less likely to be impacted by Japanese knotweed damage. 

This new guidance is backed by research findings. Thus, the previous 7-metre rule used as the basis for property valuation and surveys is no longer applicable. In addition, the guidance includes reporting Japanese knotweed infestation 3 metres from the property’s boundaries.

In effect, some lending companies are becoming more open in mortgage approvals for Japanese knotweed-infested properties. This is considered a major step in breaking the stigma towards Japanese knotweed infestations and their effect on properties. However, most mortgage providers are still utilising the previous matrix.

Yes, in some cases, properties with Japanese knotweed are likely to be cheaper. The value of depreciation depends on the extent of the infestation, though. 

The closer the infestation to your home is, the more likely it’s going to decrease in value. In effect, up to 15% of property depreciation occurs.

For example, the presence of Japanese knotweed that’s 7 metres away from the property can reduce its value by 5% more or less. 

In very rare cases, an extreme degree of infestation entirely devalues a property, which means huge losses incurred on the part of the seller or owner. Even if proper action is taken to treat Japanese knotweed or a management plan is applied, a property may still depreciate by 6–9%.

Yes, the seller or homeowner should disclose information about knotweed infestation to potential buyers. Along with informing the buyers about the existing infestation, sellers often hand in proof of an ongoing or recently conducted management plan.

Meanwhile, if you’re wondering whether you can sue a seller or property seller for failing to remove Japanese knotweed and lying about knotweed infestation, the answer is yes. 

Provided that the seller or homeowner declared wrong information on the TA6 Property Information Form, you can file for charges. 

There’s been a case of a homeowner having to pay compensation of over £200,000 for selling a property infested with Japanese knotweed.

This is because a knotweed-related question is indicated in the TA6 form. Specifically, the seller will have to declare Japanese knotweed infestation in the Environmental Matters section of the form.

Even though RICS dropped the new guidance regarding the effect of Japanese knotweed, most banks and lending companies still follow the 7-metre rule. 

Under the 7-metre rule, there are four categories called the risk matrix. Properties are assessed using these categories, and these help determine mortgage approval as well:

  • Category 1: Japanese knotweed on the neighbouring property is more than 7 metres away from the property’s boundaries.
  • Category 2: Japanese knotweed from a neighbouring property is found within 7 metres of the property’s boundaries.
  • Category 3: Japanese knotweed is located within the property but is more than 7 metres from the residential area. 
  • Category 4: Japanese knotweed is found within 7 metres from the residential property and shows significant damage to structures like walls and paths.

If the property belongs to categories two or three, the mortgage provider may require a larger deposit or ask for complete eradication of the knotweed. Moreover, a follow-up survey may be required.

Meanwhile, belonging to category four may subject you to immediate disapproval.

Aside from this matrix, the general criteria, as well as the policies and rules of lending companies or banks, should be followed.

To summarise, here are the steps that you have to take to get your mortgage approved:

  1. Meet the general mortgage requirements
  2. Seek help from an RICS or PCA surveyor and pass the risk matrix 
  3. Provide evidence for a certified treatment plan, where possible
  4. Meet other requirements of your bank or lender

And voila! You’re now on your way to getting your dream property. 

However, in cases where you don’t get lucky enough to get your property mortgage, it’s not the end of the world. At the same time, all these processes may seem confusing, especially if it’s your first time applying for a mortgage.

Did you know that there are plenty of lending companies and banks out there that are willing to approve your mortgage? 

Besides that, a trustworthy mortgage broker can help route you to these banks, thus, allowing you to get approved in no time.

Yes, a mortgage broker increases your likelihood of mortgage approval with Japanese knotweed. In fact, a mortgage broker helps ease the burden by serving as your guide throughout the sometimes tedious process of getting your mortgage approved. 

Our mortgage brokers are experts in the field. With our help, we’ll be able to match you with lenders with favourable interest rates in mind. That way, you don’t have to risk paying towering interest rates or large deposits. 

Our brokers work closely with experts in the field. In short, it doesn’t matter whether the property you’re eyeing belongs in category four; we’ll figure out the best route for you. 

Aside from bridging you to lenders and giving you the best deal, mortgage brokers help seek reliable and certified surveyors and weed specialists in cases where intervention is required. Altogether, we’ll increase your chances for mortgage approval.

Yes! Since Japanese knotweed can devalue a property, you may cop on good properties with exceptional structural integrity. However, that may depend on a number of factors. 

Some of these are the extent of the infestation, the proximity to the property, and the available management plan.

The most suitable method for controlling the growth of Japanese knotweed is through the combination of appropriate herbicide application and cutting off the root system. Note that treatment may last years and must be done during the right season. 

Certified Japanese knotweed specialists best determine the right approach to tackling the invasive plant.

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