On large construction sites when work is in progress, the presence of Japanese knotweed can cause costly delays to the building process. However, where possible, Japanese knotweed can be excavated and relocated to a quarantined area of the site for treatment later, allowing work to progress as normal on the rest of the site. The Japanese knotweed infestation can be treated with a chemical application at a later, more convenient time. This means that the presence of Japanese knotweed and the excavation process does not need to slow you down.
Our main aim is to make the Japanese knotweed excavation process as seamless and hassle free as possible, causing minimal disturbance. Our excavation contractors are able to gauge the best method for tackling the problem in your specific case, creating a tailor-made plan.
When knotweed is found on site, excavation is required to make sure a site is free of knotweed, and the process is backed up by a PCA approved guarantee.
The appropriate Japanese knotweed excavation method is determined by a number of factors, such as access, timescales, and the environment. A member of our team will be able to present you with the most suitable remedy for tackling your Japanese knotweed after visiting the site. As a renowned, leading contractor in dealing with Japanese knotweed, you can trust our team to provide a bespoke solution.
To excavate, there are multiple options, all of which will depend on the site and land on which it is situated.
In dig and dump, the site is excavated, and the waste sent to landfill. As Japanese knotweed is considered ‘controlled waste’ it must have a clear disposal audit and be handled by a licensed waste carrier and disposal location.
This is the last resort and the most expensive Japanese knotweed excavation service but sometimes it is a necessity. Especially for those sites where time is a constraint or there is no area on site to manage the waste. All waste will be removed and taken to a licensed landfill site.
When creating a new house development site or larger site, often the ground must be excavated to a point anyway. Therefore, when it comes to finding the knotweed, you can remove some of it through disposal of excess soil, and other parts can be ‘capped’ with a root membrane barrier.
A root barrier caps the growth of the rhizome network and prevents it spreading any further outside the initial area.
Japanese knotweed and contaminated soil can also be buried on site inside a heat-sealed plastic membrane. This is ideal where no construction work has begun, and the site can be fully excavated to make a hole deep enough to contain the Japanese knotweed.
The burial site must not be disturbed after excavation and the re-burial location should be clearly marked on all site plans. The Environment Agency will need to be advised that the burial of Japanese Knotweed is taking place and all plans must be approved by them. It is very important that every trace of Japanese Knotweed is removed as a piece the size of your fingernail has the potential to regrow.
Where a site is large enough to host the burial of sifted and treated soil, this can be a suitable solution for those wanting a detailed approach that reduces the volume of soil that gets removed.
The soil is filtered, and any rhizome fragments are removed. While this is not a 100% guarantee, it can be used to reduce the volume of knotweed regeneration that happens within the excavated soils. A large enough site is needed to ensure the removed soil can be monitored and any knotweed growth stopped.
If the site is large, or a development is phased, then on-site relocation can be an effective way to manage Japanese knotweed. The excavated knotweed system is transported to a suitable space on site and then a longer-term herbicide treatment is applied.
For on-site relocation, you can apply for Land Remediation Tax Relief, and Japanese Knotweed Specialists can help you to claim for this.