Japanese knotweed removal London:
it does not have to stop the sale.
A line about Japanese knotweed in a survey frightens buyers and makes lenders ask questions. What they are asking for is a treatment plan with a guarantee behind it. That is a known process, and it is arranged in days.
What knotweed looks like
and what it is not.
A surveyor will usually flag a suspected plant rather than confirm it, so the first step is a specialist identification. If it is not knotweed, that is the end of it and the report can say so.
How to identify Japanese knotweed
Hollow, bamboo like stems, green with purple speckles, heart or shield shaped leaves arranged in a zigzag along the stem, and small cream flowers in late summer. In winter it dies back to brown canes that stay standing, while the crown and roots underneath stay alive. It spreads from fragments of root or stem, which is how fly tipped soil and careless digging bring it into London gardens.
Common lookalikes
Bindweed, Russian vine, Himalayan balsam, dogwood and ornamental bamboo are all mistaken for knotweed. None of them carries the same consequences for a sale.
The guarantee is what
the lender wants.
It is not an offence to have knotweed on your land. It is an offence to let it spread into the wild or onto a neighbour's land, and the waste is controlled waste that has to go to a licensed site.
Mortgage lenders treat it as a risk to the structure and to resale, so most will lend only where a specialist management plan is in place, backed by an insurance backed guarantee that is honoured even if the treating company stops trading. Once the plan and guarantee exist, the sale usually proceeds and the treatment runs in the background over the following seasons.
Surveyors now assess knotweed under RICS guidance that looks at whether the plant is causing problems and how close it is to the building, rather than applying the old blanket seven metre rule. A stand at the far end of a long garden is treated very differently from one against the back wall, and the management plan reflects that.
Herbicide over seasons,
or dig it out at once.
There are two main routes, and the right one depends on whether the ground is about to be built on.
Cutting it back, strimming or pulling it out by hand spreads fragments and makes it worse, and household herbicides rarely reach the root system, which can run several metres sideways and well below the surface.
Herbicide treatment
A programme of treatment over two to four growing seasons, with monitoring visits in between. It is the less disruptive option when nobody needs the ground soon.
Excavation and removal
The root system is dug out in one go and taken to a licensed site. It is the right choice when the ground is needed for an extension, a wall or a patio, because building over treated knotweed is not the same as building over cleared ground.
Root barriers
On larger plots, or along a boundary with a neighbour's infestation, a root barrier membrane stops it coming back across the line.
Then the building work
it was holding up.
The point of clearing knotweed is usually what comes next: the garden wall it pushed over, the fence footings, the patio, the extension and the drainage that goes with it. GMAS manages all of it as one job, sequenced so the ground is cleared before anything is built on it, with one point of contact from survey to finished garden.
For landlords and sellers, that means one fixed written quote covering the treatment plan and the repairs, rather than coordinating a specialist and a builder separately.
Knotweed removal,
in simple steps.
1. Identification survey
The plant is confirmed or ruled out, and the extent and distance from buildings recorded.
2. Management plan and guarantee
A written plan with an insurance backed guarantee, ready to hand to the lender or buyer's solicitor.
3. Treatment, then the build
Herbicide or excavation as agreed, followed by any walls, paving or extension work.
Questions we get
asked most.
Get a written
price.
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Often needed
alongside this.
Areas we cover.
We take knotweed clearance and the building work after it across all 32 London boroughs. Most of our work is in west London, in Shepherd's Bush, Hammersmith, Fulham, Kensington, Chiswick and White City, and in south west London, in Putney, Wandsworth and Wimbledon. We also work in south east London, in Greenwich, Blackheath and Lewisham.
If your property is outside these areas, call us anyway. We travel across London and will tell you honestly if a job is too far to price properly.