The job
Infinity Apartments is a residential building on Harbour Road at Hamilton in Brisbane, looking over the river towards the city. NCR, a remedial builder, was re-waterproofing the roof, and the old membrane had to come off first. The roof is a working plant deck, covered in air conditioning condensers, pipe runs, cable trays and hot water units, and all of it had to stay where it was.
NCR brought in Perfect Concrete Care to remove the membrane and prepare the slab. Our Queensland crew was on the roof from the start of July to early August 2026.
What the work involved
- Breaking the old black waterproof membrane off the roof slab with electric breakers and lifting it in sheets
- Bagging the removed membrane into bulk bags on the roof for removal
- Hand grinding the adhesive left under the membrane back to bare concrete, with every grinder on a vacuum
- Working under and around the condensers, pipe runs, supports, platforms and drains without moving or damaging any of them
- Wall cutting with chasers in the last weeks of the job
- Surface preparation across the whole roof so the waterproofer had a clean, sound slab to work on
What made it hard
Almost none of the roof was open slab. The membrane ran under rows of condensers, around pipe supports and beneath platforms and pipe racks. A floor grinder was no use in most of it, so nearly all the grinding was done by hand, in strips, around each piece of plant.
The plant stayed live the whole time. Pipework and cables had to be protected while breakers and grinders worked right next to them.
Everything came up to the roof and everything went back down. The membrane and grinding waste were bagged as the work went, and the deck was worked in sections so there was always somewhere clear to stand and stack bags.
How it was done
Each section of roof was done in the same order. Breakers got under the membrane and lifted it off, the membrane went straight into bulk bags, then the crew hand ground the adhesive off with 130 and 150 mm grinders on shrouds and vacuums until only bare concrete was left.
Around the plant the crew worked in tight strips and by hand, under the pipe racks and along the base of each wall and platform. The roof was worked area by area, from the open sections through to the enclosed plant areas, until the whole deck was done.
Outcome
The whole rooftop was handed over as bare, clean concrete in early August 2026, with the condensers, pipe runs and hot water plant left where they were and working.
Lessons learned on this job
Every job teaches the crew something. These are the ones we took from Infinity Apartments.
What worked
- Breaking the membrane off first and bagging it straight away, so the grinders were only ever working on adhesive and the deck stayed clear
- Hand grinders on vacuums for almost everything, because the plant left no room for a floor machine
- Working the roof section by section, so the waterproofer could see progress and the crew always had a clear area to work from
What was difficult
- A roof packed with live plant, pipe runs and platforms, with the membrane running under all of it
- Adhesive stuck hard to the slab under the membrane, which took far more grinding than the membrane itself
- Getting every bag of waste off a rooftop plant deck
If you have something similar
Remedial builders, strata managers and waterproofers re-doing a roof with the plant still on it need the old membrane off without touching the services. Have a look at our coating and membrane removal, surface preparation and concrete grinding pages, see a similar rooftop job at Magnoli Apartments, Palm Beach, or get in touch and tell us what is on your roof.
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Perfect Concrete Care acknowledges the Aboriginal and Torres Strait Islander people as Traditional Custodians of the country on which we live and work. We pay our respects to the Traditional Custodians and Elders past, present and future, and honour their connection to the land and ongoing contribution to society.