The job
Magnoli Apartments is a two tower apartment building on the Gold Coast Highway at Palm Beach, a few hundred metres from the surf. Remcon Group, a Gold Coast remedial contractor, was engaged to re-waterproof the roofs, plant decks and plant rooms. Before a new membrane could go down, the old one had to come off and the concrete underneath had to be sound, clean and open.
Remcon brought in Perfect Concrete Care for the removal and surface preparation. Our Queensland crew was on the roofs for 83 shifts between October 2024 and April 2025, working tower by tower and area by area as the waterproofer followed behind.
What the work involved
- Grinding the old waterproof membrane off the main roof slabs of both towers, back to bare concrete
- Grinding the parapet hobs, upstands, plant enclosure hobs and box gutters, flat and vertical faces, so the new membrane could turn up and bond
- Stripping the plant deck slabs under the air conditioning condensers and the plant room floors around the hot water plant, with the equipment left in place and running
- Working around lift overruns, vents, drains, fixings and penetrations by hand grinder
- Breaking out and removing a section of roof topping where the remedial scope called for it
- Surface preparation to a clean, sound profile, with the grinding dust captured, bagged and taken off the roof
What made it hard
Everything was on a roof, on the beachfront, in a building people were living in. Dust control was not optional: the membrane came off under HEPA vacuum extraction and the waste was bagged on the roof and carried down. Weather set the pace more than once, with shifts rained off or held while the slab dried out, because you cannot grind a wet roof clean.
The plant areas were the awkward ones. Condensers, hot water units, pipework and cable trays were all live and bolted to the slab. The membrane under and around them had to come off without moving the plant or damaging a pipe, which meant hand grinding in tight strips and around every plinth.
Hobs and upstands take longer than flat slab. Each face has to be ground separately, the corners are done by hand, and there were a lot of metres of hob across two roofs, the plant enclosures and the perimeter gutters.
How it was done
The main roof slabs were ground with a planetary floor grinder on a HEPA vacuum, working in passes across the slab until the membrane was gone and the concrete was open. Hand grinders on dust shrouds did the hobs, upstands, gutters, plinths and everything within reach of a penetration or a piece of plant.
The roofs were worked in sections agreed with Remcon so the waterproofer could start on a finished area while we moved to the next one, and the crew shifted from one tower to the other as areas were released. Grinding waste was bagged on the roof each day and the work area left clean.
Outcome
Both roofs, the hobs, the plant decks and the plant room floors handed to the waterproofer as bare, clean concrete, area by area, from October 2024 through to the last visit in April 2025. Remcon has since brought us back on further remedial jobs along the Gold Coast.
If you have something similar
Remedial contractors, body corporate managers and builders re-waterproofing an occupied building need the old membrane off cleanly, with the dust controlled and the plant left working. Have a look at our waterproofing and membrane removal Gold Coast, concrete grinding Gold Coast and coating and membrane removal pages, or get in touch and tell us what is on the 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.