The Problem
A 300mm concrete stormwater drain servicing a Sydney CBD hotel and commercial office block was leaking.
Eight metres of it had failed. On paper that’s a small section of pipe — but it sat underneath a building that couldn’t stop trading, on a street that couldn’t be closed, connected to drainage and cooling systems that a working hotel depends on hour to hour.
The pipe itself was never going to be the hard part. Getting to it without shutting down a hotel was.
What we found
We inspected and quoted the drain on site before any work was scheduled.
The failure was confined to an 8-metre run of the 300mm concrete line, with the pipe still holding its shape. That made it a candidate for relining rather than replacement — and on a site like this the distinction is worth far more than the cost of the pipe. Replacing 8 metres of stormwater drain under a CBD hotel means excavation, traffic management, and a building operating around a work site for weeks.
Relining meant one day.
How we fixed it
The whole pipe relining was completed in a single Saturday.
1. Site assessment and quote. We assessed the drain on site and worked through the access, shutdown and staging requirements with the client’s facilities team before quoting. On a live commercial site, the plan matters as much as the price.
2. Access and pipe preparation. An access point was cut into the 300mm concrete line to launch the liner from. The section was then cleaned back and prepared so the liner had a sound surface to bond to.
3. Liner preparation. The liner was measured to the run and impregnated with UV resin — measured and prepared on site, because a liner cut short or over-saturated is a liner that fails.
4. Installation. The 300mm liner was inserted and positioned across the full 8-metre failed section, covering every leak point.
5. UV curing. A 300mm UV light train was run through the liner to cure the resin in place, bonding it to the interior of the old concrete pipe and forming a new jointless pipe inside it.
6. Post-installation inspection. A CCTV run to confirm the liner had cured evenly and flow was clear end to end.
The challenges
Eight metres of pipe. A day’s work. And a hotel, an office block, a CBD street and a cooling system to work around.
The building couldn’t stop trading. Work was scheduled for a Saturday so the office block was empty and hotel operations were at their least affected. That gave a single fixed window with no option to run over into Monday.
Cooling towers and drainage had to be taken offline. Both had to be paused for the duration of the works and brought back up the same day — coordinated with the client’s facilities team rather than assumed.
Stormwater had to keep flowing. With the line open, stormwater was redirected for the duration so nothing backed up into the building.
The street had to keep moving. Working in the CBD meant traffic coordination and a secured work zone, on a footpath with public moving through it.
None of that is pipework. All of it is why the job was quoted at one day and delivered in one day.
The result
Eight metres of stormwater drain sealed and back to full flow, in a single Saturday, with the hotel trading and the office block open on Monday.
- Leak sealed across the full failed section.
- No excavation of the site. No open trench, no weeks of disruption, no reinstatement bill.
- Cooling towers and drainage back online the same day.
- Verified on camera with post-installation CCTV footage handed to the client.
- Corrosion and root resistant. The relined section is jointless, which removes the two things that most commonly kill concrete stormwater lines.
What it means if you have the same problem
Most facilities managers assume a failing stormwater line means an excavation and a fortnight of disruption, and quote it to their board that way.
For a pipe that’s cracked but still holding its shape, it usually doesn’t. This job was 8 metres under a working hotel and it took one Saturday — and the reason it took one Saturday is that the shutdowns, the stormwater diversion and the traffic management were planned before anyone turned up, not worked out on the day.
If you’ve got a stormwater line failing under a building that can’t close, get it camera-inspected and get a plan before you accept an excavation quote. We inspect and quote free, and the footage is yours.
