Roof Slab Waterproofing in Rosebank

Location: Rosebank, Johannesburg
Service: Roof slab maintenance and waterproofing (ArmTec HyperFlex System)

Flat concrete roof slabs are one of the most common leak points on homes across Johannesburg North, and once the waterproofing membrane starts to fail, the damage rarely stays on the roof. This case study looks at a typical slab renewal job: an aging membrane that had reached the end of its lifespan and needed a full strip-back and rebuild.

The problem

The existing waterproofing membrane had delaminated and cracked across the slab, lifting away from the surface it was meant to protect. The worst damage showed up at the joints. On top of that, the drainage outlets sat too high and were poorly positioned, so rainwater puddled in front of them instead of running off.

The solution

As an approved SealPro applicator, the team installed the full ArmTec waterproofing system:

1. Correct the drainage. The outlets were opened up to restore proper waterflow.
2. Prep and prime the substrate. The whole slab was cleaned back to a sound surface and primed with Penetrar.
3. Reinforce the weak points. Cracks and delaminated joints were bridged with a Flex and StretchSeal membrane.
4. Build the waterproof layer. HyperFlex was applied and embedded with ArmTec reinforcing mesh across the slab.
5. Seal and finish. The system was topped with HydroSeal HF.

The result

The slab now carries a seamless grey ArmTec membrane from parapet to parapet, with the outlets corrected so water runs off the way it should. No more separating joints, no more puddling.

Prime Seal Spray is an approved SealPro applicator serving Rosebank and the greater Johannesburg North area.

Related Prime Seal Spray services: roof waterproofing · waterproofing & painting across Johannesburg North · waterproofing & painting in Randburg.

Contact Prime Seal Spray for a free inspection and quote: 064 879 3553 · primesealspray.co.za

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