Waterproof Concrete

Hydrostop expert Marek Mularczyk discusses waterproof concrete and its real-life application challenges.

Are you considering waterproofing but unsure which materials to choose?

Together with Hydrostop expert Marek Mularczyk, we have prepared a short series dedicated to waterproofing. Here, you’ll find answers to key questions:

• What is waterproofing?
• How is waterproofing applied?
• Is foundation waterproofing necessary?
• What is waterproof concrete?

What is Waterproof Concrete?

For many years, waterproof concrete has been a popular solution in construction. However, based on my experience working in a prefabricated concrete plant, I’ve learned that concrete is only waterproof under laboratory conditions.

As a young engineer, I was responsible for testing concrete samples—they were perfectly prepared, stored in ideal humidity conditions, and carefully maintained. Naturally, the results always came out excellent.

But construction sites are not laboratories. In real-life conditions, we have limited control over environmental factors, which significantly affect concrete performance. What happens to waterproof concrete in these conditions? Unfortunately, it stops being waterproof.

What Can Go Wrong in Waterproof Concrete Technology?

Production Errors at the Concrete Plant

• Incorrect mix design—wrong aggregate selection or incorrect cement-to-water ratio.
• Delivery mix-up—even a small error in batch preparation can cause failure.

Transportation Issues

• Concrete should be poured within 50 minutes of mixing.
• Traffic delays can result in over-aged concrete, which should be discarded.
• Adding water on-site (to improve workability) compromises the water-cement ratio, making the concrete non-waterproof.

Poor Installation on Site

• Incorrect waterproof joint tapes—improper selection, faulty installation, or weak welding can lead to leaks.
• Improper concrete placement—dropping concrete from too great a height causes segregation of the mix.
• Inadequate vibration—either too short, too long, or using an insufficiently deep vibrator, leading to honeycombing and weak spots.

Inadequate Concrete Curing

• Curing is as important as pouring. After placement, concrete must be maintained at the correct moisture and temperature levels.
• If too dry → it must be watered.
• If too wet → it must be protected from rainfall.
• If too cold → it must be heated to prevent freezing.

Each of these human errors can render waterproof concrete ineffective.

What’s the Solution?

Assume that concrete is NOT waterproof by itself.

To ensure a truly waterproof structure, additional mineral-based sealing materials should be used to close any cracks and micro-damage.

This brings us back to Hydrostop—a solution that effectively seals cracks in concrete, ensuring true waterproofing. The best approach is to anticipate potential execution errors and prepare in advance to eliminate them.

HYDROSTOP Technology