Types of Waterproofing Material

When people call me about leaks or damp walls, one of the first things they ask is, “What’s the best waterproof material to use?” It’s a fair question — with so many options out there, it can be confusing to know which one will actually last. After 30+ years in waterproofing around Johannesburg, I’ve worked with every material you can imagine, and I’ve seen firsthand how much of a difference the right choice makes for each surface.

In this post, I’ll break down the main types of waterproof materials we use, where they work best, and what I recommend for long-term protection in our local climate.

Bitumen-Based Waterproofing Materials

Bitumen is one of the oldest and most trusted waterproof materials — and for good reason. It’s strong, flexible, and can handle Johannesburg’s temperature swings.

You’ll find it in torch-on membranes, which we often use on flat concrete roofs, balconies, and parking decks. When properly applied with heat, the membrane forms a thick, seamless layer that keeps out water for years.

Last month, for example, I helped a client in Randburg whose old flat roof was leaking badly. The previous contractor had used cheap acrylic paint instead of a membrane. We removed everything, installed a 4mm bitumen torch-on system, and sealed it with aluminium UV paint. The difference was night and day — no more leaks, even after heavy rain.

Best for: Flat roofs, balconies, parapet walls, and large concrete surfaces.

Learn more about Torch-On Waterproofing Membranes in Johannesburg and how they protect flat roofs for the long term.

Cementitious Waterproofing

Cementitious coatings are easy to apply and great for internal waterproofing. We often use them in basements, water tanks, bathrooms, and retaining walls where there’s constant moisture pressure.

They bond well to concrete and brick, forming a hard, durable layer that blocks water but still lets the wall “breathe.” I’ve seen many homes in Roodepoort with damp patches caused by poor or missing cementitious coating behind tiles or plaster. Once properly sealed, those walls stay dry for years.

Best for: Basements, retaining walls, bathrooms, and wet rooms.

See how Basement Waterproofing in Johannesburg and Bathroom Waterproofing in Johannesburg help prevent rising damp and interior leaks.

Liquid Rubber Waterproofing

Liquid rubber systems are one of my favourites for metal roofs, gutters, skylights, and other tricky surfaces. They’re applied as a thick liquid that dries into a flexible, seamless membrane — almost like a giant rubber sheet that stretches with your roof as it expands and contracts.

The key advantage is flexibility. Metal roofs move a lot with heat, and rigid materials often crack over time. Liquid rubber handles that movement beautifully.

Best for: Metal roofs, skylights, gutters, and detailed roof areas.

We use Liquid Rubber Waterproofing Systems to seal metal roofs and stop leaks from rust or expansion.

Acrylic and Elastomeric Coatings

Acrylic waterproof paints are ideal for walls that need extra weatherproofing. These coatings reflect sunlight, resist UV damage, and keep out rain. However, they shouldn’t be confused with proper waterproof membranes — they’re best for maintenance and protection, not for fixing active leaks.

I often use elastomeric coatings as a final layer over a repaired roof or parapet wall to extend its lifespan. Think of it as sunscreen for your home — not the main barrier, but an added layer of defence.

Best for: Exterior walls, parapets, and roof maintenance.

Learn more about our Protective Coatings Services and how they help prevent future leaks.

Polyurethane and Epoxy Systems

These are high-performance waterproofing systems usually reserved for industrial or high-traffic areas like balconies, parking decks, or exposed concrete slabs. They’re more expensive but extremely durable, with excellent chemical and UV resistance.

When we install polyurethane coatings, they create a tough, flexible layer that resists cracking and peeling — perfect for surfaces that get foot traffic or water pooling.

Best for: Balconies, parking decks, and industrial areas.

If your balcony is leaking or has cracked coatings, see our Balcony Waterproofing Services for durable solutions.

Choosing the Right Waterproof Material

There’s no one-size-fits-all solution. The right material depends on the surface type, exposure, and problem you’re trying to solve. A bitumen membrane might be perfect for a flat roof, but completely wrong for a damp interior wall.

That’s why I always inspect the site first — even small cracks or trapped moisture can change what’s needed. Using the wrong product can lead to wasted money and recurring leaks.

If you’re unsure where to start, take a look at our Waterproofing Services Overview to understand which system best fits your home.

Final Thoughts

If you’re not sure which waterproofing material to use, don’t guess. Each type has its place, and applying the wrong one can make the problem worse. I offer free call-outs across most of Johannesburg, and I’ll help you choose the right system for your home.

If you’re dealing with leaks, damp walls, or roof problems, send me a message — I’ll take a look and give you honest advice on the best long-term fix.

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