How much does it cost to remove Japanese knotweed?
Costs for knotweed removal depends on the treatment or excavation method you opt for, and the various considerations we outline in this article.
HERBICIDE TREATMENT COSTS
If you’re happy to have a longer-term in-situ solution, knotweed can be controlled through a series of herbicide treatments delivered at the best time of the year for the herbicide to be effective. Costs are usually detailed in a Knotweed Management Plan (KMP) which will also outline the treatment schedule. The quote usually follows a site or property survey carried out by one of our qualified surveyors, and all findings from the site survey will be included in the KMP document.
We provide 5 or 10 year term plans, with a 10 Year KMP recommended for residential property. Ideal for buyers and sellers, as well as homeowners, this provides a long term professionally delivered herbicide treatment programme with guarantee (and guarantee insurance) that is accepted by lenders.
Herbicide control plans are the most cost-effective way to deal with Japanese knotweed. Plans for small infestations can typically range between £1,800 and £2,500 but always seek a survey and quote from us.
The larger the infestation the greater the cost, and other considerations including requirements for 2-person working (to satisfy health and safety concerns, such as work on steep slopes) will impact on cost as well.
Herbicide control plans are appropriate if accompanying long term restrictions on the use of the treatment area are desirable, and there are no plans to disturb or change the use the treatment area (i.e. development).
EXCAVATION COSTS
If you want to completely get rid of a knotweed problem (referred to as ‘eradicated’), then excavation is required. Excavation removes the plants underground rhizome system, from which the plants grows and spreads. The underground rhizome system spreads out further than the visible above ground extent of the plant and requires an expert eye to ensure the rhizome is correctly identified and removed. Excavation can be carried out on residential properties as well as commercial land/property and development/construction sites, and costs will depend on the following factors:
- The size (area) of knotweed infested ground s.
- Volume of knotweed contaminated soils to be excavated.
- Method of waste disposal, with options to remove to landfill, or bury or relocate onsite.
- Site specific considerations – such as retained trees or underground services.
- Environmental factors – such as protection of endangered species.
We need to survey the site before providing a cost for excavation as there are many factors which can affect the cost of works. Once we have all the information we need, including your requirements, we can provide a KMP document that will include all survey findings, our site specific recommended excavation method options, and of course our costs.
We’re experienced, qualified, funded and licensed to handle contracts of all sizes, for all types of clients, on all types of sites. The smallest of excavations will typically cost from £4,000 and a history of excavation contract values undertaken generally ranges from £4,000 up to £150,000 depending on the work in hand.
Occasionally we complete some really large contracts including a single excavation project on HS2 completed for just under £1.5 million. We utilised a methodology which reportedly saved the client an estimated £1.8m in comparison to more traditional remediation approaches (assessment made by project consultant AECOM).
In summary
Japanese knotweed remediation costs require careful consideration of all factors listed in this article (sometimes more). Attempting to deal with knotweed yourself, or opting for the cheapest quote often comes with risk, and problems down the line. Using a specialist knotweed contractor to survey and quote will enable you to make a fully informed decision. We’re here to help with any questions you may have. Speak to the team today and be knotweed savvy!
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