Roof Slab Waterproofing in Sasolburg

Location: Sasolburg, Free State
Service: Roof Slab Maintenance & Waterproofing

A flat concrete roof slab had reached the end of its waterproofing life. Years of UV exposure and thermal movement had taken their toll, and the existing membrane was no longer keeping water out. An approved SealPro applicator was brought in to strip back the failed system and reinstate a durable, fully bonded waterproofing layer across the entire roof deck.

The problem

On inspection, the roof showed several classic signs of an ageing waterproofing system nearing failure. The existing membrane had delaminated and cracked in multiple areas, breaking the waterproof seal, while joints and laps were separating and creating open pathways for water ingress. Water was puddling in front of several outlets — a sign that drainage falls had degraded and water was no longer running off as designed. The coating had also lost its UV protection, leaving the substrate underneath exposed and vulnerable, and flashing details at the parapet walls and upstands were deteriorating, with cracked cement fillets and lifting edges. Left unaddressed, this combination of failed joints, ponding water and UV-degraded coating would have led to water tracking into the slab itself, risking damage to the structure and the ceilings below.

The solution

The applicator specified a SealPro flat-slab waterproofing system built for exactly this kind of failed, aged concrete deck. The remedial process covered the full roof slab and followed these steps:

1. Strip and prepare the substrate — All loose, cracked and delaminated sections of the old membrane were removed, along with any debris and contamination, to expose a sound working surface.
2. Repair joints and details — Cracked joints, parapet upstands and outlet surrounds were repaired and detailed before any coating went down, closing off the points where water had been getting in.
3. Prime the substrate — A bonding primer was applied across the full roof area to promote adhesion and seal the porous concrete surface.
4. Apply the waterproofing system — The membrane was rolled on in overlapping bands to build an even, fully bonded, seamless waterproof layer across the whole slab, including any adjoining sections tied into the same roof structure.
5. Quality control and finish — Each section was checked for full coverage and consistent thickness before moving on, with drainage points, pipe boots and upstands finished off last to complete the waterproof seal at every detail.

The result

The roof now carries a continuous, UV-stable membrane with no open joints, no delaminated patches, and correctly sealed drainage points and flashing details. The ponding that had been forming in front of the outlets is gone, and the roof is protected against the sun and rain for years to come, backed by the standard manufacturer warranty on the system.

This is the kind of slab failure we see on older flat-roof properties throughout the region: a membrane that’s quietly cracked, delaminated or lost its UV protection long before a leak shows up on the ceiling below. SealAll Roof Contractors is an approved SealPro applicator serving Vereeniging, Sasolburg and the greater Vaal region, bringing the same strip, repair, prime and waterproof process to every slab roof job we take on.

Related SealAll Roof Contractors services: concrete slab waterproofing · roof waterproofing · torch-on alternative waterproofing across the Vaal Triangle.

Contact SealAll Roof Contractors for a free inspection and quote: 072 694 9243 · roofcontractors.co.za

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