Trenchless Sewer Repair: Which Fix for Which Defect?

Chapters

Each chapter opens the video at that point on YouTube. Read the script under each chapter. From the subtitle track delivered with the video. Refer to the video and product documentation for technical details.

1. 010:00Trenchless sewer repair: which fix for which defect?

   Trenchless sewer repair can fix a leak from inside, with no trench. But only if the fix matches the defect. Under this road, a sewer joint has opened. The street stays closed to diggers. The repair goes in through the manhole.

2. 020:14Infiltration vs exfiltration: which way is the sewer leaking?

   First question: which way is the water moving? If the water table sits above the pipe, groundwater pushes in through the gap. That's infiltration. If the sewer runs full, sewage pushes out into the soil. That's exfiltration. It's hydrostatics: pressure equals density, times g, times head. Ten metres of water make about one bar. Three metres of groundwater press about zero point three bar. Water that gets in drags sand along, and leaves voids under the road. And the direction can flip with the seasons. Groundwater rises and pushes in from outside. Then a storm surcharges the sewer, and the push comes from inside. So a joint repair has to hold both ways.

3. 030:56Which trenchless sewer repair fits each defect?

   A leaking joint gets an internal pipe joint seal. A rubber sleeve spans the gap, and stainless steel bands press it onto both pipe ends. Published ratings: twenty-five bar from inside, and five bar from outside on request. A local crack with water running in is different. Running water washes out resin before it cures, so a mechanical sleeve goes in. The packer opens it; a toothed strip locks it open. The EPDM jacket seals at once. No cure time. A crack you can keep dry suits a sectional point repair: a CIPP patch, cured in place. A repair packer carries the resin and fiberglass in, and inflates it onto the wall. In summer the resin cures in about forty minutes. A bypass packer lets the flow pass meanwhile. The packer comes out. The patch stays. So read the camera survey, and match the fix to the defect. Leaking joint: an internal joint seal. Crack under running water: a mechanical sleeve. Dry crack: a sectional patch. Damage all along the run: that's a job for full-length lining.

4. 042:01How long should a sectional point repair be?

   A point repair is longer than the crack. It must land on sound pipe at both ends. The guide sets at least seventy-five millimetres each side, and one hundred where the groundwater head is over three metres. A four-hundred-millimetre crack needs a five-hundred-and-fifty-millimetre patch. And the packer must be at least one hundred millimetres longer: six hundred and fifty.

5. 052:24Sectional point repair or full CIPP relining?

   When does a patch stop making sense? When defects cover more than twenty percent of the reach, or the pipe is more than ten percent out of round. Then the whole run is lined, from one manhole to the next. That full-length lining system is not a Reliance product; the point-repair tools are. But with one or two isolated defects in a sound reach, the published guide puts a sectional repair at twenty to forty percent of the cost of relining it all. So the survey decides: patch the points, or reline the run. To match the equipment, send four things. The pipe material, and the internal diameter measured at the defect. The defect length, and its distance from the manhole on the CCTV log. The groundwater head above the pipe, and the manhole opening you work through. Send us your CCTV findings and pipe size, and we'll match the seal, sleeve or packer to the defect.