Waterproof concrete | How does concrete become waterproof?

Waterproof concrete is a necessary requirement in many situations.

Therefore, knowing that traditional concrete is not waterproof, in this article we will answer a series of questions that will help to know more about this subject.

Is concrete waterproof?

Concrete is not 100 percent waterproof in the classic mix. The most popular concrete strength classes C 16/20 as well as C 20/25, retain some amounts of water in addition to the corresponding pressure.

They can also absorb moisture to a certain depth if they are exposed to it permanently or under high pressure. The water resistance of the concrete also depends on how well it has already dried and hardened.

Fresh, wet concrete is more susceptible to repeated irrigation than completely “finished” concrete, which can be worked on house, garden, bridge, office building and factory hall.

Waterproof cement, an alternative?

Explaining first that it is the cement, we can say that this, cement is a binder used in the mixing and tempering of concrete. Is part of the mixture that contains the concrete.

Sand, gravel, crushed stone or chippings are used as aggregates. Additional admixtures and additives are added to this basic mixture depending on the construction or DIY project.

If you want to make the concrete waterproof, you can buy various admixtures and types of cement on the market to keep the moisture away from the finished building material as much as possible.

These additional ingredients for the composite material have one advantage: they ensure water resistance at every point of the component. This means that the concrete is still waterproofed even if the upper layers have flaked off.

However, the products sold under names such as Zementmix, Cement Mix, Water-free Concrete and the like have one disadvantage: they do not harden or seal the concrete.

This means that the surface of the concrete component remains porous.

It may not allow moisture or moisture to penetrate, but the water and dirt can continue to accumulate in the superficial pores and microorganisms can multiply.

Thus, bacteria have the possibility to attack the component and as a result mosses, lichens, algae and other harmful organisms will grow. This happens the more the unsealed and hardened surface is damaged.

Ergo: Using waterproof cement to mix concrete is one solution, but by no means the optimal one. The best option will always be the polishing and sealing of the concrete.

Concrete sealing for smooth, water-resistant surfaces

If you decide to use conventional concrete for your new building or if you have a concrete surface that already exists and needs to be made water-resistant, then silicification and sealing are the best means of choice.

New and existing concrete floors as well as walls and roofs made of the composite building material have a microscopic roughness on the surface. In addition, mineral salts leave the core of the concrete.

Every day the concrete therefore wears off, causes dust and the pores of the surface provide space for dirt, moisture, microorganisms and other harmful influences.

Concrete sealing with BECOSAN® ensures that the concrete surface becomes smooth and free of dust formation.

In addition, silicification and sealing with microFORMULA technology results in a deep-acting finish of the building material. The agents used penetrate centimetre deep and harden the structure to such an extent that the concrete is made waterproof and resistant to oils and other liquids.

Wear and tear and spalling are less likely, mosses, lichens and algae cannot settle down and, last but not least, cleaning is considerably simplified.

The BECOSAN® treatments are ideal for concrete floors in these places and facilities:

• Industrial hall
• Garage
• Workshop
• Parking space
• Exhibition hall
• Car dealership
• Storeroom
• Underground car park
• Hobby room
• And many more

Waterproofing concrete, how does is work?

Waterproofing of concrete is possible through various polishing techniques. Waterproof cement itself is not the best option to provide a waterproofing solution. It would be sufficient to use techniques to improve conventional concrete.

Although the additives used in “waterproof cement” have a harder structure and a certain resistance to humidity, the surface of the concrete is still porous and susceptible to erosion and green growth.

Therefore, it is recommended improve the water repellency of by applying a professional sealer.

This is not just something that happens on floors, but also on concrete walls, concrete tiles and other building materials. In addition to water resistance, BECOSAN®️ combines breathability and with dirt repellency.

Concrete tightness classes

The density of the concrete, as well as the compressive strength of the concrete, can be divided into classes. In general, a distinction is made between these four concrete density classes for the construction and use of buildings:

• Class 1: Completely dry (living and working rooms, archives, server rooms, etc.)
• Class 2: Dry or slightly moist (storage for moisture-sensitive goods, cellars, boiler rooms)
• Class 3: Humid (buildings and rooms with less important or short-term use, e.g. underground car parks)
• Class 4: Damp or wet (halls or structures used for simple shelter)

Weak points for waterproofness

The waterproofness of concrete can and should be achieved by sealing the surface.

However, before and especially after construction measures, weak points may develop.

For example, the boreholes used to attach shelves, machines or other wall elements, as well as the holes in the floor caused by the fixation of machines and components, serve as inlets for moisture and wetness.

Therefore, these holes, but also joints between concrete components and similar openings or gaps, must always be sealed watertight.

Depending on the type of weak point and location (inside or outside), simple silicone can be used as a closure.

What is horizontal waterproofing against humidity?

Horizontal waterproofing against humidity consists of a seal applied to the wall, usually in the form of a liquid that reacts with the building material once applied.

This internal water barrier ensures that moisture cannot penetrate from a lower level (basement, underground car park) or from the ground to the wall, also know as rising damp.

Therefore, moisture problems are not only a problem for concrete floors, but also for walls in homes and industrial buildings, roofs, etc.

PROPERLA offers a large vairiety of water-repellents for this purpose.

Please feel free to contact us if you are interested.