Is Concrete Waterproof?

Posted By:Dynamic Concrete Pumping , Date: Oct 23, 2020

While you might see rain pooling on top of your concrete driveway, that doesn’t mean it’s waterproof. Concrete allows water through it because it’s a porous and permeable material. However, modern technology has given rise to methods of making concrete more moisture-resistant. Waterproofing concrete creates a strengthened structure that lets in minimal moisture and deteriorates slower than conventional concrete.

Below, we answer the most frequently asked questions about water’s impact on concrete’s structure and strength.

Is Concrete Porous to Water?

A porous material has pores, or holes, through which water or gas can pass through. Traditional concrete is a porous material with little holes that can draw in water. These holes are formed during curing when the mixture of cement, water and aggregates hardens and the excess moisture escapes, leaving behind a network of capillaries. The openings to these tunnels appear on the surface as pores.

As it cures, concrete also forms voids and microcracks invisible to the naked eye but larger than water molecules and sufficient for water vapor to seep through. Concrete’s porosity varies depending on the mixture, but its cured form is still porous. It won’t block out liquids, but there are a few ways to make concrete waterproof or water-resistant.

Is Concrete Water Permeable?

Permeability refers to how well liquids or gases can pass through a material. Concrete is permeable because water can flow through the pores and microcracks. However, it’s only permeable by small water particles and not large pools of water. Its permeability allows water to flow through it from below the ground or from the concrete’s surface.

Does Concrete Absorb Water?

Concrete can absorb moisture from the surrounding environment, depending on the relative humidity. Absorption happens when the relative humidity is high. Water vapor evaporates from the concrete into the environment when relative humidity is low. The moisture is pulled into the air pockets of the concrete through a process known as capillary action.

How Does Water Damage Concrete?

Water can benefit concrete by creating more durable and robust surfaces. However, excessive or uncontrolled moisture on or below the concrete surface may result in significant damage. As water flows through the capillary system, it can wear away at the tunnels, eventually creating larger and larger pockets to move through and causing more erosion.

Repeated or constant exposure to moisture or water also creates stains on the surface. The staining manifests as lighter or darker variations of the concrete’s original color. When combined with copper salts, the discoloration blackens. Additionally, moisture in concrete creates a prime breeding ground for mold and mildew growth, which stains concrete and damages its integrity.

Freeze-thaw is another form of water damage that affects concrete. It’s the process by which erosion and ice work together to create large, damaging cracks in concrete. Freeze-thaw occurs during cold weather when water moves into the pores of the concrete and freezes. Freezing expands the water and adds pressure to the capillary system and the concrete or rock. This process repeats as temperatures rise and fall and can quickly lead to deterioration.

How Do You Make Concrete Waterproof or Water-Resistant?

Waterproofing concrete has numerous advantages, including enhancing its performance and longevity. It slows down deterioration from water damage, ensuring it maintains a fresh look for longer. Waterproofing also helps prevent the growth of mold and mildew spores.

Here are some effective ways to make concrete waterproof or water-resistant:

Use less water in the mixture: Reducing the water in a concrete mixture results in fewer air pockets being trapped in the capillary pores. Of course, you’ll still have to meet the minimum requirements to maintain the concrete’s structure.
Mix products into the concrete: Additives are mixed with concrete to improve water resistance. Waterproof cement is one example that provides concrete with superior moisture resistance and additional structural strength.
Add a waterproof or water-resistant coating: Certain types of surface coatings for concrete finishing can make the concrete more resistant to water. As a bonus, some can also offer ultraviolet protection.
Scheduling concrete installation for the right time: Pouring concrete during periods of high rainfall or humidity may affect its ability to absorb or permeate water. Heavy rain exposure during the curing process affects the structural integrity of set concrete.
Applying crystalline solutions: These are chemical coatings applied to the concrete, just like paint. The solution reacts with the concrete to create crystals that block the capillaries.
Polishing the concrete: This is the process of grinding and buffing the concrete to create a smooth and water-resistant surface. Polished concrete surfaces are stronger, easier to maintain and eliminate the need for chemical-based sealants.

Request Full-Service Concrete Placing and Finishing Services

Waterproofed concrete is possible when you work with experts in concrete pumping, pouring and placing. Dynamic Concrete Pumping is the leading source of concrete grinding services in Calgary with over 40 years of experience. We use innovative tools such as diamond abrasives, hardeners, protective sealants and stain guards to prevent water resistance and ensure your floors withstand heavy use and traffic.