Roof Slab Waterproofing: A SealPro ArmTec Case Study
Concrete roof slab waterproofing (SealPro ArmTec system) — installed as a complete SealPro system by BloemGuard.
A leaking roof slab rarely announces itself on the slab. It shows up on the walls and ceilings below as blistering paint, damp patches and crumbling plaster. That is exactly the pattern in this case study: a large flat concrete terrace slab that had lost its waterproofing, letting moisture track down through the structure into the rooms underneath. The failed system had to be stripped back completely and rebuilt with a proper waterproofing layer across the full deck.
The problem
The slab had been sitting without an effective waterproofing membrane, and the surrounding walls told the story. Paint had lifted and blistered off the render in large flakes, the plaster behind it had gone soft, and moisture was clearly moving through the deck. Standing water and poor drainage detailing around the outlets had accelerated the failure. Left untreated, this kind of slab keeps feeding water into the concrete and the rooms below, and the damage only spreads.
The solution
Working to the SealPro ArmTec specification for horizontal concrete decks that take standing water and foot traffic, the slab was rebuilt in four stages:
- Prep and prime. The slab was cleaned back to a sound, contaminant-free surface, failed areas were cut out, and the substrate was primed to lock down the concrete and guarantee adhesion.
- Detail the weak points. Perimeter upstands, outlets and joints were reinforced with a flexible waterproof coating bedded over stretch-bandage tape, sealing every crack and edge where water finds a way in.
- Reinforced membrane. A high-build waterproof membrane was laid over the deck with reinforcing mesh embedded through it, building a tough, fully reinforced layer that bridges movement instead of tearing over it.
- Waterproof topcoat. The system was sealed with a UV-stable waterproof coating and finished with a tile-ready topcoat, leaving a durable, even surface ready for the client's chosen final finish.
The result
The slab became a continuous, seamless waterproof deck with the outlets properly sealed and the detailing tidied up. The finish is uniform and hard-wearing, the standing-water problem is resolved, and the moisture path into the walls and rooms below has been cut off at the source. The client was left with a terrace that is protected, functional and ready for years of use.
This is the standard we bring to every roof slab we waterproof. BloemGuard is an approved SealPro applicator serving Langenhoven Park and the greater Bloemfontein area, and we follow this same system on every slab we treat — from prep and priming through to the final waterproof topcoat.
Contact BloemGuard for a free inspection and quote: 072 933 0162 · bloemguard.co.za
The work, step by step
