Drainage capacity in Wandsworth: the usual causes
Wandsworth is classic late-Victorian terraced London, with long rows of family houses between the commons and a growing number of side-return and loft extensions. Those extensions frequently build over the original drain run, which changes how a blockage has to be reached.
Building over or near an existing drain brings its own requirements, and getting that wrong is expensive to correct once the structure is up.
The River Wandle and the Thames both influence surface water here, and gardens are often paved or decked over former soakaways. The typical fault is a partly collapsed or root-affected clay lateral at the rear, showing up as a slow gully and a smell after rain.
How we deal with drainage capacity in Wandsworth
The sequence is survey, design, fixed quote, installation, then a camera check before we backfill.
- Survey the existing drainage and establish where a new run can connect
- Design the layout with the falls, diameters and access points it needs
- Confirm a fixed price against that design before any work starts
- Excavate, lay and bed the pipework, and build the chambers
- Camera the finished run and test it before backfilling and reinstating
Rear gardens are usually reached through the house, so we protect floors on the way through. Where an extension covers the drain run, a camera survey is the quickest way to find the fault without lifting slabs.
Signs it needs attention now
- An extension or loft conversion adding bathrooms to the property
- A garden that floods or stays waterlogged after rain
- A paved or decked area with nowhere for surface water to go
- Drainage that was never adapted after a previous alteration
- A property being converted into flats with new kitchens and bathrooms
What we see most often in Wandsworth
- Root ingress at clay joints in rear gardens with mature planting
- Drain runs built over by side-return extensions, with no remaining access
- Rear gullies flooding where the garden has been paved or decked
Wandsworth is mostly family houses, and a large share of our work here follows an extension or a loft conversion. We also survey drains for buyers before exchange, which in this housing stock is money well spent.
Equipment and what happens afterwards
Installation work uses pipe, fittings, chambers and bedding material specified for the job rather than whatever is on the van. Falls are set with a level rather than by eye, and chambers are positioned where they will still be reachable in ten years, not where they are easiest to build today.
Before anything is backfilled we camera the new run and test it, so any issue is found while the trench is still open. You get that footage, a description of what was installed and where the access points are. Reinstatement is agreed in advance and included in the fixed price rather than treated as an extra.
What drainage installation cost in Wandsworth
Installation work typically runs from £600 to £2,500 depending on the scope, and the fixed price is confirmed after a site visit. There is no call-out charge in Wandsworth, at any hour, and the price you are given on the call is the price you pay.
Areas we cover around Wandsworth
Our Wandsworth work covers SW18, SW11, SW12 and SW17 and the rest of Wandsworth. Engineers are usually 60 to 90 minutes away, and because we also cover Battersea, Clapham, Balham and Putney, a job that crosses a boundary does not need a second contractor.