Concrete Waterproofing: Everything You Should Know

Is Concrete Waterproof?

No, concrete is not a completely waterproof material. It consists of impervious and porous substances. These substances absorb water and other liquids over time. When the porous are saturated with water, concrete tends to seep water through the concrete layer. This can lead to damage to the concrete by cracking, erosion, and damage to the reinforcement.

Is Concrete Water Resistant?

Yes, concrete is a water-resistant material due to its dense microstructure, low permeability, and the formation of calcium silicate hydrate gel during hydration. This helps to block capillary pores and slows water penetration through concrete.

What is Concrete Waterproofing?

Concrete waterproofing is the process of making concrete structures prevent to water penetration by applying waterproof membranes, protective treatments, or additives that block moisture ingress. Concrete waterproofing helps to prevent water damage, extend the structure’s lifespan, reduce maintenance costs, and improve both the durability and appearance of concrete surfaces.

What Methods can be Used to Waterproof Concrete?

You can use cementitious waterproofing, admixture waterproofing, and sheet membrane waterproofing as concrete waterproofing membranes. Among them, cementitious and sheet waterproofing membranes are external waterproofing, while admixture waterproofing membranes are integral membranes.

Cementitious Waterproofing for Concrete

The cementitious waterproofing membrane is a type of waterproofing coating material that is made with cement compound to apply on concrete surfaces. It is applied on the surface as a liquid. After the cementitious membrane is applied on the surface, it builds a crystalline barrier that helps to prevent water from penetrating through the layer. The 3 main types of cementitious membranes are cementitious application, cementitious rigid application, and cementitious flexible application.

Cementious waterproof membranes are higher breathable, UV resistant, and flexible. Hence it can withstand more than 10 years as a successful waterproof membrane on the concrete.

Admixture for Concrete Waterproofing

Admixture concrete waterproofing is a type of integral waterproofing membrane to make the concrete waterproof itself. Waterproof admixtures are added to the concrete while it is batching. Waterproof admixture forms insoluble crystals that fill the pores and capillaries in the concrete, and it reduces the porosity, permeability, and capillary action of the concrete.

Does Waterproof Admixture Reduce the Concrete Workability?

Waterproof admixtures do not reduce the concrete workability because it forms a catalyst during the concrete hardening process.

Sheet Membranes for Concrete Waterproofing

Concrete can be waterproofed using sheet membranes on external surfaces. Sheet membrane waterproofing is applied on the concrete surface using a specific adhesive. It acts as a protective layer on the concrete surface. Once the layer is damaged, water can penetrate the concrete easily. The most commonly used sheet membrane waterproofings are PVC, HDPE, EPDM, and Hypolon.

What are the Waterproof Adhesives for Concrete?

Waterproof adhesives are external waterproofing materials that are used to apply to the concrete surface to prevent water ingress.

The most commonly used waterproof adhesives are waterproof sealant, paint, caulk, epoxy, glue, and plaster. These adhesives are used for different purposes in various construction applications. These are used as an optional waterproof membrane to the concrete when the above concrete waterproofing method is difficult to use.

Waterproof Sealant for Concrete

Waterproof sealant for concrete is a type of coating applied to the surface of the concrete to prevent lower rate water and moisture penetration into the concrete. Waterproof sealants are made with acrylic, polyurethane, and polyurea-based materials. These sealants are mainly water-based, acrylic-based, and hybrid bio-polyurethane. You can seal both older and newer concrete surfaces using these sealants.

The most used concrete sealants are BEHR Premium, Eagle Supreme Sealer, Foundation Armor, Eagle Gloss Gloss Coat, and RadonSeal concrete sealers.  Waterproof sealant creates a barrier against water on the concrete surface to prevent damage such as cracking, spalling, and efflorescence caused by water absorption. The advantages of waterproof sealants are more durability, resistance to mold and mildew, ease of maintenance and improved appearance.

Waterproof Paint for Concrete

Waterproof paint for concrete is a type of paint that can provide a waterproof barrier on concrete surfaces. These paints work by penetrating into the concrete and reacting chemically with it, while others create a surface coating that repels water. Waterproof paint can be used on both interior and exterior concrete surfaces, including basements, bathrooms, garages, patios, and many other construction purposes.

Concrete waterproof paints are easy to use, can protect against water and moisture, are easy to maintain, have an aesthetic appeal, and can be used for a wide range of applications. However, it is not suitable for higher water engagement areas.

Waterproof Caulk for Concrete

Waterproof caulk for concrete is a type of concrete sealant that is used to fill cracks, gaps, or joints in concrete to prevent water and air infiltration. It can be used in various applications such as between concrete slabs, filling cracks in walls or floors, and sealing around windows or doors in concrete structures. The advantages of concrete caulk are easy to apply, more flexible, long-lasting, and more durable.

Waterproof Epoxy for Concrete

Epoxy is a watertight and air tight layer that can be used to fully seal the concrete surface. Epoxy coating is a hard, airtight, abrasion resistant coating.

Waterproof epoxy is durable, easy to maintain, resistant to chemicals, and a safer waterproofing material. Hence, it can be used in areas that are frequently exposed to moisture, such as basements, garages, and outdoor patios.

How Long Can a Waterproof Concrete Last?

A properly waterproofed concrete can last between 20-50 years. The durability of the waterproof concrete depends on the quality of the concrete mixture, the environment it is exposed to, the waterproofing method, and the maintenance of the waterproofing layer.

The admixture waterproof concrete will last longer than sheet membrane or cementitious waterproof concrete.

How to Damage Waterproof Concrete?

Waterproof concrete can be damaged due to environmental impacts and human activities. These are the nine most 9 damaged ways of waterproof concrete.

1. Expose the waterproof concrete to extreme weather conditions
2. Expose the waterproof concrete to the UV light
3. Expose the waterproof concrete to higher temperature fluctuations
4. Expose the waterproof concrete to harsh chemicals, acids, and alkaline
5. Physical impact or abrasions on the concrete surface
6. Poor waterproofing and construction practices
7. Fewer maintenance and repairs
8. Water erosion over time
9. Heavy loads and bearings on the surface

Is Waterproof Concrete Damaged by the Fire?

Yes, the waterproof concrete can be damaged by fire. The most damaged waterproofing method on concrete is sheet membrane waterproofing. Sheet membranes such as PVC, EPDM, and HDPE can be melted, and their joints can be loosened even in small fires. But cementitious waterproofing can withstand more than that.

Admixture-based waterproofing can last long until the concrete cracks or forms damage through the layer. Additionally, the heat can weaken the concrete’s structure, reducing its load-bearing capacity of the concrete.

Is Waterproof Concrete Sustainable?

Yes, waterproof concrete can be considered as sustainable due to these 3 main reasons such as more durability, and energy efficiency.

Waterproof concrete is durable: Waterproof concrete structures can last for many decades. It does not require frequent replacement or repair.

Waterproof concrete can save energy: Waterproof concrete provides good insulation to the building. It reduces the energy consumption for heating and cooling.

Is Waterproof Concrete Resistant to Chemicals?

Yes, waterproof concrete is resistant to some mild chemicals. But waterproof concrete can be damaged when it is open to harsh chemicals like acids, solvents, or specific types of salts over time. The resistance level of the waterproof concrete can depend on the specific type of waterproofing agent used in the concrete.

Among them, epoxy waterproofing is the most chemically resistant waterproof membrane, while cementitious waterproofing is the least chemically resistant waterproof membrane.

The sheet waterproofing membrane for concrete waterproofing has a higher level of chemical resistance. But those can be damaged when it is exposed directly over time.

Is Waterproof Concrete UV Resistant?

Yes, waterproof concrete is UV resistant because most waterproofing membranes are resistant to UV rays. Before waterproofing concrete for outdoor purposes, you should choose waterproofing membranes that are resistant to sunlight.

What are the 5 Concrete Defects for Water Leaking?

These are the 5 concrete defects that cause to leak of water from the concrete layer. These are cracks in the concrete, honeycombs, capillary pores in the concrete, poor joints and sealings, and construction defects such as improper slope, poor drainage systems, and use of low quality materials.

1. Cracks in the concrete: Concrete cracks can be caused by shrinkage, thermal changes, or structural stress. These cracks tend to leak water through the cracking paths.
2. Honeycomb in the concrete: Concrete honeycomb is caused by improper vibration or mix design during the pouring process. Water can flow through the honeycombs due to a lack of materials.
3. Capillary pores in the concrete: Capillary pores are tiny channels that can allow water to seep through if the concrete is not properly cured.
4. Poor joint sealing in the concrete: If the joints between concrete slabs or sections are not sealed correctly, water can leak through.
5. Construction defects in the concrete: These can include issues like improper slope, poor drainage design, or use of low-quality materials. These tend to leak water through the defective lines.

Is Cement Waterproof?

Regular cement (Portland cement) is not a waterproof material. It is a highly water resistant material. Cement is a highly permeable material that allows moisture and air through the solid layer even when it is mixed with aggregates to form concrete, plaster, and mortar.

Is Higher Strength Concrete Waterproof?

Higher strength concrete is recognized as a compressive strength greater than 42 MPa.

But higher strength concrete is not waterproof. Because the concrete is naturally porous and it can absorb the water regardless of its strength. But higher strength concrete is less permeable than lower-strength concrete; hence, it is less susceptible to water damage.

Is Waterproof Concrete Stronger than Regular Concrete?

There is no strength difference between waterproof concrete and regular concrete because the strength of concrete is determined by other factors, such as the type and amount of aggregate used, admixtures, the amount of cement in the mix, and the curing process.

Waterproof concrete is considered concrete that has been treated or mixed in a way that reduces its natural porosity. Hence, it is more resistant to water penetration. It helps to increase the durability and lifespan of the concrete, particularly in wet or humid environments.

Is there any Waterproof Cement?

Yes, waterproof cement is available. These waterproof cement types are manufactured by adding waterproofing agents and water repellent chemicals during the manufacturing process.