The Terror-Cotta Nightmare Waiting Under a Premium Sydney Suburb
If you’re in Drummoyne or East Ryde there’s a good chance that your home is still connected to the original terracotta drainage pipes. Drummoyne was subdivided from 1881, and its Federation era homes are well over a century old, but the same clay pipework was used in homes right through to the early 1980, when PVC took over as the standard. So, if your home was built before then, it’s a fairly safe bet that your pipes haven’t held up as well as your home.
Terracotta, also called vitrified clay, was the standard material for sewer and stormwater pipes for most of the twentieth century because it was cheap and easy to lay, not because it held up well over time. Not only are pipe sections brittle, they’re joined every metre or so rather than run as one continuous line, and each of those joints is a potential weak point that can shift or crack as the ground moves. It’s also porous, which isn’t an issue under normal conditions, but far from ideal during dry spells when the soil around your pipes dries out.
Why Dry Ground and Tree Roots Can Spell Disaster for Your Pipes
During dry conditions tree roots pull moisture from the soil around them which creates a pressure imbalance in the ground known as matric suction, where drier soil pulls moisture towards it from any nearby source. A terracotta pipe with even a hairline gap becomes the most reliable water source for a thirsty root system, and the root will grow towards it, force it way into the joint and keep expanding once inside. Over time that widens the gap it entered through, which is how a small leak under your lawn turns into a cracked pipe and can eventually lead to a full blockage or collapse.
Homes in other Sydney suburbs aren’t immune either, tree roots are responsible for most major drain blockages across the city generally. Between 2010 and 2019, researchers studying Sydney’s sewer network found almost 3,000 root related blockages across 103 suburbs. It’s simply that older, leafy suburbs like Drummoyne and East Ryde are more at risk than newer areas due to the ageing clay pipes and more mature root systems in the ground.
And if you want more proof that your terracotta pipes may be in need of replacement, repair or relining, an industry trial testing clay, concrete and PVC pipes over 32 months found clay pipes came off worst, with roots breaking into 7 out of 8 clay joints in that time.
What To Do About It
If your home was built prior to the 1980s, its worth getting ahead of the problem rather than waiting for blocked drains. A plumber who specifically works with older clay systems can run a camera through the line and tell you whether it needs to be relined or replaced before it turns into a bigger issue. Local plumbers in Drummoyne or plumbers in East Ryde deal with this exact problem regularly, so getting one to check your line sooner rather than later can save you a lot of time, money and mess down the track.
