Why would you need an Exploratory Dig?
If you are planning on building an extension, patio, driveway or simply looking to re-landscape and need to excavate before proceeding, an exploratory dig identifies the presence of underground Japanese knotweed roots and rhizomes and how close to the proposed works they have spread. The benefit is that the true extent of any Japanese knotweed infestation is discovered, the exact location to which it has spread and how much excavation needs to take place. The exploratory dig will enable us to quote you accurately for a knotweed excavation. Please note that the investigation will only be in the vicinity of the identified knotweed area and will not cover the entire garden.
Cost in the region of £250.00 plus vat
Below we show you an example of the type of report you would receive should you direct us to carry out an exploratory dig on your property.
Proposed Exploratory Excavation Areas
- All areas/zones of knotweed are approximate and indicative
- The light blue area indicates the subject property and the dark blue indicates the property’s boundary
- The risk zone is based upon the visible knotweed identified at the time of our survey and is drawn in accordance with the RICS risk table and guidance from the Environment Agency’s Knotweed Code of Practice
Description of Propsed Works
The proposed area for the trial digs is shown in the photos below:
Images: Area with proposed dig area along paved area, pathway and at the base of the brick wall
The access is down the side of the building (down two sets of steps in the front garden) and through the site gate. The work is in the rear garden and involves:-
- The excavation of the paved aread spans the width of the garden with a depth of 4.7m measured from the rear boundary fence and sub station. The pathway and brickwall are situated in an excavation area of 2m depth measured from the side fence and 8.9m in length along the right hand side of the garden in the flower bed.
- Excavation holes are shown by the black circles in the plan above. All will be to a depth of approximately 600mm (24 inches) deep with each hole measuring approximately 300 x 300mm.
- All the arising’s are inspected carefully to identify knotweed roots and rhizomes.
- Pictures are taken of each hole and the arising’s from each hole.
- Arising’s are placed back into the holes.
- The area is made good. Plants that had to be removed are replaned and the garden is left neat and tidy.
Exploratory Dig Findings and Recommendations
Photographs taken during the dig are used in the subsequent report, with a complete explanation on what was found. Examples are given below.
Images above show "hole 3" with evidence of knotweed rhizomes and roots
Images above show measuring of the site and setting up
Images above show the trial hole with no knotweed and the arisings, again showing no knotweed
Images above show (from left to right) the sum of all the arisings and the garden after the dig, left clean and tidy
You will additionally receive a report per hole that was dug. See below.
- Identify accurate areas for excavation
- Identify presence of underground knotweed roots & rhizomes
- Full extent of knotweed growth established
- Identify exact location of knotweed roots
- Only £250 (approx) plus VAT