Japanese knotweed excavation & the Party Wall Act
Japanese knotweed excavations are quite often challenging and require methodical planning to ensure everything runs as smoothly as possible. But how is the excavation of Japanese knotweed affected by the Party Wall Act? Contractors engaging in the removal of invasive weed species, where such activities involve excavation of soil to remove propagules, then Section 6 of the Act may apply. For example, where excavations take place lower than the foundations of an adjacent property, and within a range of 3 metres.
As we understand, most medium/large Japanese knotweed infestations will likely have a rhizome depth beyond many property foundations, it should therefore be assumed all works within 3 metres of adjacent properties may need to be classed as ‘notifiable works’ until, and unless, a Party Wall Surveyor or Structural Engineer says otherwise.
Providing Notice of Works
Provide notice at least one month prior to excavation commences, as this is a written legal document that informs the Adjoining Owners of the intention to carry out works that would be covered by the Act. Notices can be served by the Building Owner or a Surveyor acting on their behalf. Once a Notice has been served, the Adjoining Owner essentially has three choices:
- to consent
- to dissent, or
- provide a counteroffer setting modifications or amendments to the work
If consent is not provided within 14 days, the matter is then considered to have automatically defaulted, i.e. gone into a dispute.
What further advice can you give?
It is clear that responsibility under the Act falls on property owners who intend to undertake projects, which in so doing involve notifiable works, e.g. full depth excavations of Japanese knotweed. However, there is a duty of care on contractors (effectively acting as agents for owners doing work) to ensure that their clients are aware of the Act and when their project includes notifiable works.
Clearly it is in the contractor’s interest to ensure, as far as is practicable, that their clients are abiding by the requirements of the Party Wall Act from the outset, to enable realistic programming of works to take place. If no provision has been made and the process has to start from scratch, project start times and monetary budgets are almost certainly going to be affected.
Japanese knotweed and other INNS (Invasive Non-Native Species) are often tied to different legislation, from ensuring its control in the “wild”, to specific waste removal conditions. Checking for buried services, or conducting soil analysis for nasties like asbestos or even hydrocarbons have become the norm during excavations. So, if the Party Wall Act isn't part of your due diligence checks to ensure you and your client are fully compliant, perhaps it should be?
For more information and further guidance, you can access and download Party Wall Agreement from the PCA's Technical Document Library, or via the button below:
Party Wall Act >>