Soakaway failure repair across London

A soakaway is a buried void that disperses surface water from your downpipes and patio drains into the surrounding subsoil. When it fails, the symptoms are obvious: standing water around the downpipe base after rainfall, gulleys that surcharge through the grating, waterlogged lawns above the soakaway footprint, and damp patches creeping up the lower courses of brickwork. In a wet London winter a failed soakaway can saturate the ground within metres of your foundations, and over time that hydrostatic loading is exactly what drives basement damp, cracked render, and movement of shallow Victorian footings. Soakaway failure rarely fixes itself, and percolation through compacted clay subsoils in north and east London is often the underlying reason the original design was never going to last.

We diagnose, dig out, and rebuild failed soakaways across all 33 London boroughs, working to BS 8000 part 14 for site practice and BRE Digest 365 for soakaway sizing and percolation testing. Most repairs we attend involve replacing legacy rubble-filled pits with modern geotextile-wrapped soakaway crates (typical capacity 200 to 600 litres per crate) sized against a fresh percolation test on the actual ground conditions. We coordinate the works around your downpipe runs, gulleys, and any rainwater harvesting tanks already on site, and where the local water table or clay content makes a soakaway uneconomic we will say so up front and price the alternative permitted connection instead.

How we deliver

No surprises, no upselling. The exact path every job follows.

1. 1
   Site survey and downpipe trace
   We map every downpipe feeding the suspected soakaway, dye-test the run, and confirm the failure is the soakaway and not a collapsed lateral or blocked gulley upstream.
2. 2
   BRE Digest 365 percolation test
   Trial pit dug to design depth, soaked overnight, then timed three-pass drop test to derive the soil infiltration rate. Without this number any soakaway is guesswork.
3. 3
   Sizing calculation
   Effective storage volume calculated against contributing roof area and the measured infiltration rate, all to BS 8000 part 14 with the 10-year return-period rainfall figures for your borough.
4. 4
   Excavation and removal
   Failed pit fully excavated, legacy rubble or broken concrete rings carted off site, and the void inspected for groundwater ingress before backfill design is finalised.
5. 5
   Soakaway crate installation
   Modular soakaway crates stacked to required volume, fully wrapped in non-woven geotextile membrane, inlet pipework dressed in at the correct invert and protected from silt loading.
6. 6
   Backfill, compaction, and reinstatement
   Pea shingle surround, free-draining backfill to subgrade, and topsoil, slabs, or block paving reinstated to match the existing surface.
7. 7
   Commissioning flood test
   Bowser-fed flood test through the downpipes, drawdown timed and recorded, photo and video evidence retained for Building Control or your insurer.
8. 8
   Written report and warranty
   PDF report with percolation results, crate schedule, photographs, and a workmanship warranty you can hand to a conveyancer or loss adjuster.