Knotweed rhizome crown held in hand
specialist control services

japanese knotweed EXCAVATION & REMOVAL

Excavation is a permanent solution to completely remove Japanese knotweed, and is suitable for residential or commercial properties. Often chosen to enable a property sale or change of land use and to avoid costly delays to building projects.

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 EXCAVATION METHODS

Japanese knotweed plant removal is usually carried out via excavation. The method chosen depends on the growing season, property or site access, and often the type of site and any environmental considerations required, such as protected species or underground infrastructure.

Once the site has been surveyed, you’ll receive a Knotweed Management Plan (KMP) which details the survey findings, proposed excavation works and Japanese knotweed removal cost.

japanese knotweed removal questions

FULL EXCAVATION & REMOVAL TO LANDFILL

This provides an instant and impressive rectification method to the problem of Japanese knotweed. On completion the knotweed has been completely removed, allowing for unimpeded development of the area.

Although the least sustainable of our methods, our approach and ethos puts the emphasis firmly on reducing quantities of waste removed to landfills, and hence cost to the customer.

This is done via expert accurate identification of rhizome extent in the soils, ensuring complete removal while only removing those soils that possess the rhizome.

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Dumper truck ready to unload soil or ground at construction site.

REDUCED LEVEL EXCAVATION & ROOT BARRIER CAPPING

To reduce the cost of excavation it may be feasible in some situations only to excavate to a set depth, and then use root barriers to cap and retain any further deeper knotweed contaminated ground. This is particularly cost-effective when the development formation level (the depth ground levels need to be reduced to allow for construction) is less than 1m deep.

The proprietary root barriers are installed to fully contain the remaining knotweed contaminated ground and prevent its re-emergence. Expert installation and bonding ensure the complete integrity of the barrier. The contained non-excavated knotweed is therefore sustainably remediated on-site.

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Japanese knotweed Root barrier being installed in excavated ground

SIFTING OF EXCAVATED CONTAMINATED WASTE

Sifting of the excavated knotweed waste soils can be used to lessen the volume of knotweed material within them. This method however cannot be guaranteed to remove all knotweed rhizomes and therefore the treated sifted soils will still need to be handled as potentially knotweed contaminated.

The reduction in the growth potential following sifting makes these soils more re-useable on site, either in burial or relocation for monitoring. If they are removed from the site they will still be classed as controlled waste due to potential or known knotweed contamination.

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Close up of an excavator foot filled with contaminated ground and soil

DISPOSAL OF EXCAVATED KNOTWEED WASTE ON-SITE AS A CELL BURIAL

As well as providing instant eradication of the knotweed, it allows fully sustainable disposal of the excavated waste on-site in accordance with Government RPS 178. The method requires a suitable size and location where the waste can be buried. The area can be sizable due to the logistics and specifications for burial, with soft landscaped public open space (POS) being among the desirable areas to place a burial.

A deep receival pit is excavated, deep enough so that at least 2m of clean fill can be placed above the deposited buried knotweed waste. The knotweed waste is deposited within the pit, encapsulated in a root barrier, which is referred to as the cell. By residing 2m below finished ground levels it helps protect the cell against future accidental human disturbance or burrowing animals.

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Excavation site with cell barrier being laid in the ground

RELOCATION OF EXCAVATED MATTER

In some situations, it may be possible to relocate knotweed from an undesirable location to another location on-site where it can be treated long term with herbicides. This provides the instant eradication of the knotweed from its current location (to enable development for example), while sustainably retaining and treating the knotweed on site.

The excavated waste is carefully double-handled over site along designated haul routes between the locations. Often only suitable for larger sites, the knotweed is relocated as a formed stockpile or landscape bund where any re-growth of knotweed is treated with herbicide. Once the knotweed growth has been controlled the relocated area can be carefully seeded or planted.

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Dumper truck transporting excavated ground

vacuum excavation

Vacuum excavation involves the use of suction generated by a vacuum lorry delivered via an air lance in order to agitate and remove material (typically soil, earth or water) from the ground. Compressed air is directed through an insulated air excavation lance to loosen, agitate, or aerate the ground initially. The loosened debris is then safely removed by the vacuum.

The vacuum extraction method is used when we need to work around infrastructure or natural habitats. Using less equipment and vehicles on site also reduces our carbon footprint. Being able to work around trees and live utilities without risk of harm or strike makes it a safer and more sustainable option that is kinder to the environment. It is generally a quicker and more efficient method of knotweed removal as it limits disruption to local residents, businesses and services.

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Vacuum excavator drilling into the ground

brush cutting

Brush cutting old knotweed stems allows access and increased visibility of new growth so we’re not fighting through old canes when the next treatment cycle begins. Knotweed canes create dense areas that can also block natural light and is therefore a threat to biodiversity. Typically we carry out brush cutting over the winter months in readiness for the spring regrowth when we can then excavate and remove knotweed from site.

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Before and after images showing vegetation clearance

BOOK A SURVEY

Taking control of Japanese knotweed all starts with a survey

Why choose us

  • We have over 1000 5-Star ratings on Trustpilot and enjoy long-standing relationships with our customers
  • Our excavation  teams are highly accredited and certified to the highest standards
  • We have a range of excavation methods to remove Japanese knotweed once and for all
  • We have all the equipment that we need, as well as the necessary experience to work on construction sites
A stem of Japanese knotweed leaves

residential client testimonial

Here’s what one of our clients had to say after we completed a residential excavation to remove knotweed:

“We wanted to pass on what a great job the guys did. They were very thorough and cleared every patch we asked them to look at. We had asked them to be careful around our newly planted hedge and they went the extra mile to carefully dig out the plants they needed to get past and replanted them after they were finished so a big thank you to both of them. 

We’d like to add that the guys were really lovely and made what was a stressful time, much easier.”

Penny and Ben W.

Small digger breaking up slabs in residential garden

LAND REMEDIATION TAX RELIEF (LRR)

What is LRR?

Originally LRR was designed to encourage investment in land that was previously derelict or contaminated so it can be made purposeful again. It is a generous tax incentive intended to promote the remediation and development of land and buildings affected by Japanese knotweed or chemical contaminants such as Asbestos. It helps offset some of the cost of remediation services (which can include man-hours on the project, such as the Project Manager) through capital gains tax relief.

Who Can Claim?

With Japanese knotweed or contaminated grounds. The claimant must be the owner (adopter) at the time of the works and pay capital gains tax. Successful claims can result in capital gains tax refunds on qualifying work values of up to:

  • 150% for the land owners
  • 50% for developers

However, many property owners are either not aware of the scheme, or not clear of the qualifying criteria for making a claim, and could be missing out on this valuable cash-back incentive. Given that claims can be made that continue year-on-year for ongoing treatments, and can be claimed retrospectively for up to 3 years.

How Do I Make a Claim?

We can provide you with the best and most up to date industry information and advice on whether you can claim, and if so how to kickstart the process. Click the button and you will be able to download a useful fact-sheet about LRR as well as contact us about an LRR claim.

EASILY APPLY FOR LRR

Image of derelict building on a brownfield site

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