No-dig pipe relining
across Chatswood

A new pipe formed inside the old one. A resin-saturated liner goes into the damaged section, is inflated so it presses against the existing pipe wall, and cures hard. You end up with a continuous jointless pipe inside the original, sealing the cracks and open joints that were letting roots or groundwater in. The old pipe stays where it is and becomes the mould. Nothing is excavated except, sometimes, one small access point.

Because of what is under the lawn. Chatswood sits on Hawkesbury Sandstone, and across much of the North Shore that rock is within a metre or two of the surface. It is hard stone, measured up to around 70 megapascals, the same material that was quarried by hand to build colonial Sydney. Digging a trench through it is not a shovel job, it is rock saws and breakers, and the cost and the noise scale accordingly. West of here the ground is clay and excavation is comparatively cheap, so the relining argument is much weaker. Here it is often the difference between a day's work and a fortnight of it.

Sandstone in this area is not a flat slab. The formation carries shale lenses, thin bands of laminite generally under a metre thick but tens or hundreds of metres across, so depth to rock changes over short distances. One property can be into sandstone at 400mm while the house next door digs two metres of soil. That is exactly why we do not quote excavation from an address, and why the camera and a locate come first.

Both are common candidates around here. The older Federation and interwar houses through Chatswood West and the surrounding streets often still run original cast iron stacks and earthenware below ground, and the failure mode is corrosion, open joints and root intrusion rather than the pipe being gone entirely. A liner bridges all of it in one pass. What cannot be lined is a pipe that has collapsed or lost so much wall that there is nothing to line against, and the camera tells us which you have before anyone quotes.

When the pipe has collapsed, when it has deformed too far for a liner to seat, when the real fault is fall rather than sealing, or when the damage sits in soft ground close to an existing access point. That last one is rarer here than it is out west, but it happens, and when it does we will tell you that digging is cheaper. We would rather lose the bigger job than sell you the wrong one.

It depends where the fault is, not where the symptom shows. The line inside your lot is generally yours. The shared stack and the common drainage below it are generally the owners corporation's. A blockage low in a shared stack surfaces in whichever apartment sits closest to it, which is why the flat with the problem is very often not the flat with the fault. Camera footage is what settles that conversation with a strata manager, and we hand it over as a matter of course.

Standard residential lining runs roughly $500 to $900 per metre once the length, the diameter and the access are known. The camera inspection first is $300 to $750 and it is not optional, because quoting this work without seeing the pipe is guessing. Junction reinstatement and any access pit are quoted separately. Compare it against a rock excavation quote before deciding, because on this ground the gap is usually wide.