JKW Excavation and on-going treatment plan: Residential
To supervise as a watching brief for the excavation of Japanese Knotweed contaminated materials and providing the controlled waste removal. Works were followed on with a 3 year treatment plan with a guarantee.
This project was very challenging due to the ‘party wall agreement’ and the fact the JKW had grown under and through the boundary wall but the wall could not be undermined. To add to the complexity next to the wall was the gas mains that had to be identified and had dug around. A drop in levels also had to be created so shuttering was installed to make the site safe. Other challenges were access and parking issues which forced us to suspend parking bays, stockpile material and plan quick removal by grab lorries.
We were asked to supervise the main contractor as a watching brief during the excavation of the area affected by Japanese Knotweed in the front garden of the property. We were also required to dispose of the materials at a licenced landfill. On arrival to site, trial digs had been commenced by the main contractor and contaminated soil had been stock piled within the site. Evidence of Japanese Knotweed Rhizomes were discovered and further investigation uncovered evidence of rhizomes growing into the boundary wall between the subject property and the property directly next door. All trial digs to the rear of the property showed no evidence of Japanese Knotweed being present. 30 tonnes of controlled waste were removed using a registered and licenced waste carrier to suitable and licenced landfill. A 3 year treatment plan to the neighbouring and subject property were also put in place which include a two-year monitoring programme in-line with the PCA guidelines is now in place.