At SE Knotweed, a root-barrier membrane is a certified vertical or horizontal barrier installed to stop knotweed rhizome crossing a boundary or reaching a structure. It contains the plant rather than killing it, so it is usually paired with treatment on the affected side.
A root-barrier membrane costs from around £1,500 to £6,000 depending on the length and depth of the run, and we confirm the figure at survey.
At SE Knotweed, a root-barrier membrane is a certified geomembrane installed in the ground to block knotweed rhizome from crossing a line, used to protect a boundary, a building, a driveway or a drainage run.
It is a containment and screening method, not a kill, so it holds the plant on one side while the stand itself is treated. It is the method to reach for when knotweed is arriving from next door and you need to stop it advancing.
We install the barrier either vertically, in a trench along a boundary or structure to a depth below the rhizome, or horizontally beneath a capping layer where knotweed sits under a planned surface. The membrane is a knotweed-grade geomembrane, overlapped and welded or taped at every joint so there is no gap.
Depth and run length are set from the survey, because a rhizome can travel several metres, and the barrier must go deeper and wider than the stand it contains.
A barrier is used when the aim is to stop encroachment rather than clear a stand, for example where knotweed is spreading from a neighbour, or to protect a new extension from a stand that will be treated over time.
Where the knotweed is on your own ground and must be gone, excavation or a herbicide programme deals with the plant itself, and a barrier alone would only pen it in.
A root-barrier membrane costs from around £1,500 to £6,000, driven mainly by the length and depth of the run and how much excavation the trench needs. A short boundary screen sits at the lower end and a deep run along a long boundary at the higher end.
We measure the run at survey and give a fixed figure, so please treat the range as indicative.
A barrier contains but does not kill, so on its own it leaves living rhizome in the ground. For that reason we usually pair it with treatment on the affected side as a combination, and back the work with an insurance-backed guarantee where the situation allows.
Where a barrier is purely protecting your land from a neighbour's stand, the guarantee position depends on the case, which we explain at survey.
Tell us the address and what a surveyor flagged. We confirm the plant, record the RICS category and set out the figures.