Roof Slab Waterproofing in Craighall Park

Location: Craighall Park, Johannesburg
Service: Roof Slab Maintenance & Waterproofing (ArmTec HyperFlex System)

Flat concrete roof slabs have a shelf life, and once the waterproofing membrane starts to go, the clock is running. This case study looks at a typical flat-slab renewal carried out by a SealPro-approved applicator team, and what the same process would look like for a Johannesburg North property showing the same warning signs.

The problem

The slab in this case study had reached the end of its waterproofing lifespan. Years of UV exposure had left the old membrane brittle, cracked, and lifting at the joints. On inspection, the waterproofing showed several stages of failure: fine cracks running the full width of a bay, delamination at the joints and laps where the membrane had curled up and separated entirely, and a coating that had lost its UV protection and gone chalky, dry, and brittle.

The solution

For a slab in this condition, the brief was a full system renewal rather than a patch job. The applicator team worked through it in stages:

  1. Strip and inspect. The failed, delaminated sections of the old membrane were removed to expose sound substrate.
  2. Prep and prime. The substrate was cleaned and primed across the full slab area with Penetrar.
  3. Reinforce the weak points. Cracks and delaminated joints were strengthened first with a StretchSeal membrane, bridging the movement points.
  4. Install the ArmTec system. A full ArmTec waterproofing system was applied over the slab, sealing the surface and rebuilding the UV-resistant top layer.
  5. Return visits and topcoat finishing. The team returned to complete the HydroSeal HF topcoat and check the cured system, making sure every join and upstand was fully sealed.

The result

The slab was left with a continuous, fully bonded waterproofing membrane with no weak joints or exposed cracks. The reinforced StretchSeal detailing means the new ArmTec system is far less likely to crack again, and the fresh UV-stable topcoat gives the roof a working lifespan measured in years, not seasons.

Prime Seal Spray is an approved SealPro applicator serving Craighall Park 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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