Repairing a drain beneath a working trailer park

10 November 2026

The worst place for a drain to fail is the ground you cannot do without. On a freight yard that tends to be the concrete where the trailers park overnight, or the apron in front of the loading doors. Dig that up and you lose parking, shuffle vehicle movements around a hole for days, and then wait for new concrete to be ready to carry weight again.

Repair the defect, not the panic

Repeated blockages, a sunken patch, a smell that will not shift or a survey showing a cracked pipe do not automatically mean the whole run has to come out. The repair depends on the condition of the pipe, and that comes from a camera survey, not a guess. Broadly the choices are these:

• A patch repair, where a short liner is set over a local defect such as a cracked joint.
• A longer liner, where a resin-impregnated lining is installed along a damaged length and cured in place, forming a new pipe inside the old one.
• Excavation, where the pipe has collapsed, lost too much of its shape, or sits at the wrong level to work properly.

The appeal of relining in a yard is plain enough: much of the work happens through existing chambers, so the surface can often stay in use. That is not always possible, and an honest contractor will tell you when a pipe is past lining.

Plan the work around the traffic

Treat it as you would a vehicle off the road for repair: book it, arrange cover, and know when it comes back. The crew needs access to the relevant chambers and room for vehicles and equipment. Depending on the method and the pipe being repaired, flow may need to be stopped while the liner cures. That can affect a wash bay or welfare block served by the run. Agree those windows with the traffic office before the day, not on it.

Drain Relining covers surveys, relining, patch repairs and excavation, with the method chosen from the condition of the pipe and the limits of the repair set out before work begins. That last part matters when the drain sits under concrete you need back.

Close the job out properly

Ask for the before and after survey footage and a note of what was lined, where, and along what length. File it with the site plan. When you next sell, sublet or extend, that record shows the drain was dealt with, and it saves the next surveyor puzzling over why there is a pipe within a pipe under the trailer park.

It is worth asking, too, why the pipe failed. A rocking chamber cover is worth recording separately, as are any visible cracks in the yard surface. Lining addresses the damaged pipe; it does not repair the concrete above it or settle how trailers should be parked during the next job.