Confirming it is actually a collapse
Several faults produce similar symptoms. A heavy root mass, a hard fat plug and a badly displaced joint can all stop a camera and all cause repeat blockages, and none of them require excavation. Before anyone digs, the run should be jetted and inspected so the collapse is seen rather than inferred from the camera stopping.
The visible signs above ground are worth noting too: a sunken patch of lawn, a dip in a slabbed area, a driveway settling in one spot, or a damp smell in the same place after rain. Where those coincide with the point the camera stopped, the diagnosis is straightforward.
Locating it precisely
The camera head carries a sonde and the position is traced from the surface, giving both plan position and depth. That measurement is what keeps the excavation small. A well located collapse at one point two metres deep might need an excavation of a couple of square metres, whereas an unlocated one turns into a trench.
Depth also determines cost more than most people expect. Shallow work in a garden is quick, whereas the same repair at two and a half metres needs shoring, more spoil handling and more reinstatement.
Excavation or lining
If the pipe is fully collapsed there is no host structure to line against, so the section is dug out and replaced. If it is severely deformed but still broadly intact, some cases can be reformed and lined. If the collapse is short and the rest of the run is sound, we replace the damaged length and leave the rest alone.
Where the collapse is under a structure, a garage, a conservatory or the highway, a different approach may be needed, including a diverted run or a lined replacement fed from either side. Those cases need a plan before work starts and sometimes need consent, and we will say so up front rather than discover it on the day.
The sequence of work on site
- Jet and survey to confirm the defect and its extent.
- Trace and mark the position and depth from the surface.
- Excavate carefully by hand at depth, with shoring where required.
- Cut out the failed section and replace with new pipe and couplings, laid to the correct fall.
- Surround with pea gravel or concrete as the depth and loading require.
- Backfill in layers, compact, and reinstate the surface.
- Final CCTV inspection of the repaired run, recorded and supplied to you.
Timescales and what disruption looks like
A straightforward garden collapse at moderate depth is usually a one day job. A deeper repair, a driveway repair needing block or tarmac reinstatement, or a collapse under a structure runs to two or three days. Drainage is normally kept usable overnight, and where it cannot be we will tell you before we start so you can plan.
Reinstatement is the part quotes differ on most. Ask specifically whether the price includes replacing the surface, since relaying block paving or matching tarmac is a real cost and leaving it out makes a quote look cheaper than it is.
Cost, insurance and getting it right once
Cost is driven by depth, access, surface type and length rather than by the word collapse. A shallow two metre replacement in a lawn is a modest job. The same length under a driveway at two metres deep is several times that.
Where the cause is sudden damage rather than age, the repair may be an insurance matter, and the footage and report you get from the survey is what supports that claim. It is worth notifying the insurer before committing to full excavation, while still carrying out any emergency clearance needed to stop sewage entering the property.
Comparing quotes properly
Collapse quotes vary widely and the reason is usually scope rather than price per metre. Check whether the quote includes the survey and trace, the depth assumed, the length of pipe being replaced, whether concrete surround is included, and above all what reinstatement is covered.
Also check whether a post works CCTV inspection is included. A repair you cannot see is a repair you are taking on trust, and the footage is what proves the new section is laid to fall and running clear. We include it as standard and the recording is yours to keep.
Questions we get asked
How do I know if my drain has collapsed?
Repeat blockages in the same spot, sinking ground above the line and a camera that cannot pass a point are the usual combination.
Can a collapsed drain be lined?
Only if enough of the original pipe shape remains. A full collapse has no host pipe to line against and must be dug out.
Will you put my driveway back?
Yes, reinstatement is included in our quotes and we say clearly what finish is being restored before work starts.
Does a collapse always need urgent work?
If it is causing backing up or ground movement, yes. A partial collapse with good flow can sometimes be planned rather than done that week.