Roof Slab Waterproofing: A SealPro Case Study
Concrete roof slab maintenance and waterproofing (ArmTec System) — installed as a complete SealPro system by BloemGuard.
When the waterproofing on a flat concrete roof slab reaches the end of its life, the warning signs are hard to miss: membrane that lifts and peels, joints that crack open, and a substrate that turns brittle and starts to shed. This case study covers exactly that kind of failure on a flat concrete roof, where the owner brought in a SealPro-trained team to strip the failure back, repair the slab, and install a fresh, fully bonded waterproofing system built to last.
The problem
The existing waterproofing on the slab had delaminated and cracked. Old membrane was separating from the concrete in sheets, lifting along the joints and pulling away from the parapet walls. Underneath, the slab had gone brittle and the surface was breaking up. Water was no longer draining correctly, which only accelerated the breakdown. Left untreated, this kind of failure leads straight to interior leaks and structural damage to the deck below.
The solution
As an approved SealPro applicator, the team worked through a full remedial and re-waterproofing sequence:
- Prep and prime the substrate. The team cleared the failed membrane, opened the outlet to correct the waterflow, and prepared the concrete so the new system could key in properly.
- Bind the brittle slab. A penetrating primer was applied to consolidate and strengthen the weakened, brittle concrete surface.
- Reinforce the weak points. Cracks and delaminated joints were bridged and strengthened with a stretch-grade reinforcing membrane, and cement flashing was installed along the parapet walls to seal the critical wall-to-slab junctions.
- Install the ArmTec system. The full ArmTec build was laid down, embedding the reinforcing mesh into the coating so the slab is protected as one continuous, monolithic waterproof skin.
- Seal with a UV-stable topcoat. A tough, flexible topcoat finished the system, delivering a seamless, UV-stable membrane across the entire roof area.
The result
The slab is now finished in a clean, uniform grey membrane with no open joints, no lifting, and water directed correctly to the outlets. A large area of failing roof was renewed into a single, watertight surface backed by a proper workmanship guarantee. The parapet walls are sealed, the drainage works, and the owner has a roof that will keep the weather out for years to come.
If your own flat roof slab is showing the same signs — cracked joints, lifting membrane, ponding water — it's worth having it inspected before the damage reaches the structure below. BloemGuard is an approved SealPro applicator serving Universitas and the greater Bloemfontein area.
Contact BloemGuard for a free inspection and quote: 072 933 0162 · bloemguard.co.za
The work, step by step
