ATC-0150 · Attenuation
150m³ geocellular attenuation tank
A 150m³ geocellular attenuation tank installed on a live North London development — wrapped, welded and connected in a deep, tightly-shored excavation with a full crew on site.
- Location
- Enfield
- Region
- Greater London
- Sector
- Commercial
- Completed
- 2026
Attenuation · Enfield
150m³
- Ref
- ATC-0150
- Region
- Greater London
- Sector
- Commercial
- Year
- 2026
What we did
We supplied and installed the full crate system into a deep excavation: protective fleece, an impermeable membrane heat-welded panel to panel, the geocellular block built to the designed 150m³, and the inlet, outlet and inspection connections tied into the drainage design.
The tricky bits
Depth and access. Working a large tank into a deep, shored dig on a busy site means sequencing the crew and materials carefully and keeping the membrane clean and undamaged as it goes in. A test weld was carried out and recorded before backfill.
What we delivered
A watertight, fully tested 150m³ tank at the designed capacity, handed over with the QA pack — one of the larger single tanks we install.
The excavation
The groundworks team dug and shored the excavation; we checked the formation before anything went in. On a tank this deep, every roll of fleece and membrane has to be lowered into the dig and then cut and dressed to the tank geometry.
Testing and handover
Every joint in the membrane was heat-welded. None were taped. Before the tank was covered, a test weld was carried out and recorded, and the system was inspected.
The handover pack holds the weld test record, as-built details and a QA sign-off: the papers building control, the adopting authority and the warranty provider expect to see.
- Volume
- 150 m³
- System
- Geocellular crates
- Membrane
- Welded, test weld recorded
- Scope
- Supply & install
On site · Enfield
On site
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