How to build on land with Japanese knotweed
If you are a developer, you might wonder how to build on land with Japanese knotweed. Not only is this invasive plant expensive to remove but it can significantly delay your building projects.
At TCM, we have worked alongside builders for over twenty years, so here's our procedure for building on land affected by Japanese knotweed.
New builds and Japanese knotweed
New builds can be developed on land affected by Japanese knotweed but there are legal hoops to jump through before you start laying the foundations. Namely, as the developer and seller of the new build it is your responsibility to declare any Japanese knotweed and incorporate its management into your plans.
However, because of the stigma surrounding this invasive plant, as well as the removal costs and delays it can cause, many builders choose to ignore its existence. Even worse, and surprisingly, when it comes to selling their new build properties, developers are not required to declare the presence of Japanese knotweed to potential buyers.
Buyers beware - if you are purchasing a new build, instruct your solicitor to ask about any Japanese knotweed history on the land.
Don't ignore Japanese knotweed
At TCM, we have come across a few developers who have ignored Japanese knotweed on their land and paid the price for it later! If you lie or try to hide the presence of this plant on your land, you will be liable to misrepresentation. It is always best to seek advice and support from invasive plant experts if you are building properties to sell.
Japanese knotweed survey
Though it is not essential for a developer to have a site survey performed prior to commencing building work on a development site, a survey will provide useful information about the nature of any infestation. For example:
- Show how the infestation could affect the land and/or property
- Provide you with information on the best methods to control the infestation (or remove it completely)
- Give you an indication on how long the removal process will take, and how much it will cost
Remember, it is not crucial you employ an invasive plant removal expert to conduct a site survey but the information you glean from such a report will give you valuable insight about the site, any issues, therefore assisting you with the realistic scheduling and planning of your build.
Development and building delays
Unfortunately, the presence and removal of Japanese knotweed can significantly delay a new build development project. And how long those delays are - whether or not construction can still continue alongside the removal process - depends entirely on the characteristics of the individual infestation.
Generally, the smaller and younger the growth, the sooner you can get back to building. But be warned, if the knotweed is mature and extensive, you may have to put development plans on hold. This is the reason why getting a professional survey done in advance of any building work is money well-spent, because the findings will help you incorporate any knotweed removal process into your development timeline.
Knotweed damage
Thankfully, it is not common for Japanese knotweed to grow through new builds but it has been known to happen. With such an invasive plant, it will grow relentlessly unless treated or removed. Plus, its underground root system can grow horizontally up to seven metres. So what may visibly seem like a small knotweed shoot on the surface could be a huge rhizome spreading under the foundations of your new build causing untold damage and destruction.
Also, physical damage isn't the only damage Japanese knotweed can cause. Properties affected by Japanese knotweed can be devalued by up to 20% - and new builds are not exception. It pays dividends to eradicate this invasive weed as soon as possible.
Not sure where you stand with Japanese knotweed and construction? Contact our experienced, friendly team today to request a site survey, or discuss your development site concerns.