Blocked drains cleared
across Prospect

The clay. Dolerite weathers to a heavy clay soil, and heavy clay shrinks in dry weather and swells when it is wet. That movement is small each time and relentless over decades, and it works old pipe joints apart a fraction at a time. Once a joint has opened, roots find it and soil washes in, and the line starts blocking on a cycle. It is not something anybody in the house did, and clearing it treats the symptom rather than the opening.

It might be, but not at a price given by the metre, and that is the thing worth knowing here. Prospect sits on Sydney's largest body of igneous rock. Most of Sydney is sedimentary sandstone, which splits along its bedding and can be worked. Dolerite is what gets crushed into road base precisely because it is hard, which is why the quarry is here. So a trench can be straightforward at 400mm and a genuinely different job at 800mm. The variable is depth to rock, not length, and any quote that does not account for it is a guess.

Test holes, or simply asking the question and pricing it honestly with a stated assumption and a stated rate if rock is met earlier. Neither is complicated and both are far better than discovering it with your yard already open and very little leverage left. If a quote does not mention rock at all, it is worth asking what happens if it is hit, before agreeing to anything.

Frequently, and the reason here is unusually strong. Relining goes in through existing access points and never touches the ground, so it does not care what is underneath. On most blocks that is a convenience argument. Here it sidesteps the single biggest source of cost and uncertainty in the whole job. We will still tell you when digging is the right call, because sometimes it is.

Yes, and on a line with joints already opened by ground movement they are worse than usual. They clear the bowl and then fail to break down, and they catch on the first irregularity they meet. On a sound line that takes a while. On one with open joints and soil intrusion it is quick, which is why a house can go from coping to blocking monthly.

Rarely, and on aged pipework they do damage. They sit against the blockage rather than passing through it, they generate heat, and in old earthenware and cast iron they attack the pipe about as readily as the obstruction. If someone has poured one down, please tell us when you ring rather than after we open the line.

A standard clear through an existing access point is $150 to $400. A camera inspection with the footage handed over is $250 to $450. Jetting a root-filled line is $400 to $700. Where excavation is genuinely the answer we price it with the rock question addressed rather than left as a surprise.