Concrete Roof Waterproofing in South Africa protects concrete roof slabs from water that soaks through cracks, joints and porous concrete. Send one request and independent local waterproofing contractors reply with prices.
Say how big the slab is and where cracks or leaks show, and get quotes.
Get Waterproofing QuotesConcrete Slab Problems
- Shrinkage cracks. Fine cracks across the slab that let water through.
- Structural cracks. Wider or moving cracks that need an engineer's opinion.
- Cold joints. Joints between concrete pours that open over time.
- Wet slab. Water trapped in the slab causes blisters under new systems.
- Spalling. Concrete breaking off over rusting reinforcing steel.
Signs on the Inside
- Damp patches. Ceiling stains below the slab after rain.
- White deposits. Salt deposits on the underside of the slab.
- Rust stains. Brown streaks near cracks.
- Peeling paint. Ceiling paint that flakes or bubbles.
Methods and When They Fit
- Torch on membrane. Common on concrete roofs and suits slabs with minor movement.
- Polyurethane liquid. Bonds well to prepared concrete and handles complex details.
- Cementitious coating. Suits slabs that will be covered, such as under screeds or tiles.
- Acrylic system. Suits sound, well-draining sloped concrete roofs.
The system depends on the slab's condition, falls and use. Preparation decides how long any system lasts.
Concrete Roof Waterproofing Prices
Ballpark prices so you can sanity-check a quotation.
| Item | Ballpark price |
|---|---|
| Crack repair and preparation | R30 - R60 per m² |
| Screed to falls | R60 - R150 per m² |
| Torch on membrane, 4mm | R250 - R450 per m² |
| Polyurethane liquid membrane | R350 - R500 per m² |
| Cementitious waterproofing | R140 - R300 per m² |
| Acrylic system | R120 - R280 per m² |
Prices JUST UPDATED. Indicative ballpark figures in rand, rounded, including labour unless stated. They are not our prices or quotations, and no contractor is bound by them. Confirm VAT, access costs, the product system and what each quotation includes.
Get prices for your property rather than a range. Send one request and see who replies.
Get Waterproofing QuotesWhat Affects the Quote
- Slab condition. Many cracks or spalling concrete add repair time.
- Moisture. A wet slab may need time to dry or a system that tolerates damp.
- Old layers. Failed coatings and membranes must come off first.
- Size and access. Bigger slabs cost less per m², while access adds cost.
Substrate Preparation
Good preparation matters more than the product.
- Clean. Remove dirt, moss and loose material.
- Remove. Strip failed membranes and coatings.
- Repair. Open, fill and reinforce cracks, and repair spalled concrete.
- Level. Screed low areas so water drains.
- Dry and prime. Let the slab dry and apply the correct primer.
- Apply. Install the chosen system with details done first.
Access and Disruption
- Weather. Expect delays in wet weather while the slab dries.
- Noise. Grinding and crack chasing can be noisy and dusty.
- Inside. The home stays usable while work happens above.
Maintenance and Questions to Ask
- Watch cracks. Mark wide cracks and see whether they grow.
- Inspect. Check the roof yearly and after big storms.
- Ask. How will cracks be treated, how dry must the slab be, and is a screed needed?
Concrete Roof Waterproofing FAQs
Why does my concrete roof leak if the slab looks fine?
Fine cracks, cold joints and porous concrete let water through even when the surface looks sound.
Do all cracks need an engineer?
No. Fine shrinkage cracks are common. Wide, growing or stepped cracks should be checked by an engineer before waterproofing.
Can a wet slab be waterproofed?
Some cementitious systems tolerate damp concrete, but most membranes need a dry slab to avoid blistering.
How is this different from flat roof waterproofing?
Flat roof work focuses on drainage and details. Concrete roof work focuses on the slab itself, its cracks and its preparation.
Related Services
Get concrete roof quotes through Waterproofing South Africa and compare the crack repairs and preparation each contractor includes.
Waterproofing South Africa is a quote and referral service. We do not carry out waterproofing work and we do not employ contractors. Work is quoted and carried out by independent local contractors, and your agreement is with the one you choose. The right system depends on an inspection and the cause of the water ingress. Ask for a written quotation, the product system and the guarantee terms before you pay a deposit.
Concrete Roof Waterproofing. Describe what you need once and get the best quote, fast.
Get Waterproofing QuotesGet the Best Quote, Fast
Keep it brief. Say what is leaking or damp, the type of surface and your suburb. Your enquiry is passed only to contractors suited to the job, and you decide whether to go ahead.
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