Cementitious vs. EPOXY Waterproofing: What Are the Differences?

Written By Adam Paul - Waterproofing Expert

Cementitious waterproofing and EPOXY waterproofing are two types of most used waterproofing membranes, which are used to protect buildings from water and moisture penetration. In order to choose the right type of the waterproofing membrane, you should know the differences between them before you apply. 

So as waterproofing experts, Aqviz, we prepared a complete comparison guide by considering the cementitious vs EPOXY waterproofing.  We have included the main differences in material composition, water resistance, breathability, flexibility, chemical resistance, thermal stability, and UV resistance. As minor differences, we included adhesion, tear resistance, seam integrity, root penetration resistance, eco-friendliness, fire resistance, anti-slip resistance, toxicity and self-expanding capability. 

Material Properties Comparisons Between Cementitious and Epoxy Waterproofing

These are the material composition, performance, durability, and environmental resistance comparisons between cementitious and EPOXY waterproofing

1. Cementitious waterproofing is a cement-based coating while Epoxy waterproofing consists of epoxy resin and hardener.
2. Cementitious waterproofing has a higher waterproofing capability while epoxy waterproofing has a superior waterproofing capability.
3. Cementitious waterproofing is highly breathable while epoxy waterproofing is not breathable.
4. Cementitious and epoxy waterproofing are not flexible.
5. Cementitious waterproofing has a moderate chemical resistance and EPOXY waterproofing membranes are highly chemically resistant.
6. Cementitious waterproofing has a lower thermal stability than EPOXY waterproofing.
7. Cementitious waterproofing has a higher UV resistance than EPOXY waterproofing

Composition Difference Between Cementitious and Epoxy Waterproofing

Cementitious waterproofing is a cement-based coating while Epoxy waterproofing consists of epoxy resin and hardener.

Cementitious waterproofing is a cement-based coating that consists of mainly portland cement, kaolin, and minor additives such as marble dust or silica sand, lime,  ground salt, alum stone or calcium chloride. When it mixes with water, it forms a rigid and durable barrier against water. Hence, it can be applied on the concrete surface to stop water leaking and seeping. 

EPOXY waterproofing consists of epoxy resin and hardener. Once they mixed together to a recommended proportion, it forms a solid compound. When the epoxy compound cures, it forms a solid, non-porous layer that helps to prevent water leaking through the layer. Epoxy waterproofing is a highly water-resistant, less flexible, higher tensile strength, and highly effective for positive and negative water pressures. 

There are more than 10 types of waterproofing membranes available for building waterproofing. If you need to know about all of them, read our expert guide about 10 Types of Waterproofing Membranes: Properties, Applications, Pros, and Cons

Water Resistance Difference Between Cementitious and Epoxy Waterproofing

Cementitious waterproofing has a higher waterproofing capability while epoxy waterproofing has a superior waterproofing capability. 

Cementitious membranes provide excellent resistance against positive water pressure. Hence it can be used for water tanks, basements, bathrooms, and swimming pools. The cement-based composition allows it to bond permanently with concrete, ensuring long-term protection against water seepage.

Epoxy membranes offer superior water resistance due to their less flexibility and high tensile strength. Epoxy waterproofing effectively handles both positive and negative side water pressures.

Breathability Differences Between Cementitious and EPOXY Waterproofing

Cementitious waterproofing is highly breathable while epoxy waterproofing is not breathable.

Cementitious waterproofing is highly breathable due to its higher porosity nature. It allows moisture vapors to escape from the substrate. This makes it suitable for concrete walls and basements. This leads to mold growth and structural deterioration on the concrete surface over time.

But epoxy waterproofing membranes are not breathable due to their seamless, non-porous resin composition. Therefore, epoxy waterproofing is ideal for industrial areas and chemical storage areas. Due to the less breathability, moisture can be trapped on the surface. This causes to blistering of the layer and prolonged water-related problems over time. 

Flexibility Difference Between Cementitious and EPOXY Waterproofing

Cementitious and epoxy waterproofing are not flexible.

One of the major drawbacks of cementitious waterproofing is its rigidity. Once applied and cured, it forms a hard, inflexible layer on the concrete surface. If there is any small movement on the structure, it can be cracked easily.

Standard EPOXY waterproofing is not flexible. But some improved epoxy waterproofing can be flexible due to polymer resin compositions. We highly recommend you to use a limited flexible epoxy for the minor movable structure in order to protect the substrate properly.

Chemical Resistance Difference Between Cementitious and EPOXY Waterproofing

Cementitious waterproofing has a moderate chemical resistance and EPOXY waterproofing membranes are highly chemically resistant.

Cementitious waterproofing has moderate chemical resistance, making it suitable for water treatment plants, swimming pools, and sewage systems. It can withstand exposure to alkalinity, mild acids, and sulfates commonly found in concrete environments. However, it is vulnerable to strong acids and aggressive chemicals, which can break down the cementitious structure over time.

Epoxy waterproofing membranes, however, possess superior chemical resistance due to their robust, resin-based formulation. EPOXY waterproofing withstands exposure to harsh chemicals, solvents, and acids effectively. Therefore, epoxy waterproofing is highly recommended for industrial facilities, laboratories, garages, and chemical storage areas.

Temperature Stability Difference Between Cementitious and EPOXY Waterproofing

Cementitious waterproofing has a lower thermal stability than EPOXY waterproofing

Cementitious membranes maintain good temperature stability within typical residential ranges. But it can be cracked or deteriorated under extreme thermal fluctuations due to their rigid cement-based structure. 

Epoxy waterproofing membranes have an excellent temperature stability. It can withstand a wide range of temperature variations. Hence it is suitable for both high-temperature areas and outdoor applications exposed to severe climatic changes, such as rooftops and terraces.

UV Resistance Difference Between Cementitious and EPOXY Waterproofing

Cementitious waterproofing has a higher UV resistance than EPOXY waterproofing

Cementitious waterproofing provides higher UV resistance compared to epoxy waterproofing due to its inorganic, cement-based composition. It does not degrade under direct sunlight and maintains its waterproofing properties without requiring an additional protective layer. This makes it suitable for exposed concrete structures, terraces, and facades where UV stability is crucial.

Epoxy waterproofing membranes generally offer a lower UV resistance. Epoxy waterproofing layer can deteriorate under prolonged sun exposure, leading to discoloration, chalking, and reduced effectiveness due to UV rays. To enhance UV stability of the EPOXY waterproofing, the top coat should be applied. 

Read our similar expert guide related to cementitious waterproofing

• Cementitious vs Polyurethane waterproofing
• Cementitious vs Bituminous waterproofing
• Arcylic vs EPOXY waterproofing

Functional and Environmental Impact Comparisons Between Cementitious and EPOXY Waterproofing

These are the mechanical strength, safety, environmental impact, and usability comparisons between cementitious waterproofing and epoxy waterproofing.