Cementitious vs. Bituminous Waterproofing: What Are the Differences?

Written By Adam Paul - Waterproofing Expert

Cementitious waterproofing and bituminous waterproofing are two of the most used waterproofing membranes, and they 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 bituminous waterproofing.  We have included main differences in material composition, water resistance, breathability, flexibility, chemical resistance, 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 Bituminous Waterproofing

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

1. Cementitious waterproofing is a cement-based coating while bituminous waterproofing is derived from petroleum based bitumen.
2. Both methods offer strong water resistance, but the level of protection varies.
3. Cementitious waterproofing is highly breathable while bituminous waterproofing has a lower breathability.
4. Cementitious waterproofing is not flexible while bituminous waterproofing is highly flexible.
5. Cementitious waterproofing has a moderate chemical resistance, while bituminous waterproofing has a superior chemical resistance
6. Cementitious waterproofing has a higher UV resistance while bituminous waterproofing has a poor UV resistance.

Composition Difference Between Cementitious and Bituminous Waterproofing

Cementitious waterproofing is a cement-based coating while bituminous waterproofing is derived from petroleum based bitumen.

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. 

Bituminous waterproofing is a petroleum-based, asphalt-derived membrane. It consists of bitumen mixed with polymers and reinforced with fabrics or fiberglass to create a flexible and durable waterproof membrane. The petroleum-based nature of bituminous coatings gives them a highly effective waterproofing quality, making them a popular choice for roofs and underground structures.

Water Resistance Difference Between Cementitious and Bituminous Waterproofing

Cementitious and bituminous waterproofing have a strong water resistance, but the level of protection varies. 

Cementitious waterproofing is highly resistant to hydrostatic pressure. Hence it can be used for water tanks, basements, and swimming pools. The cement-based composition allows it to bond permanently with concrete, ensuring long-term protection against water seepage.

On the other hand, bituminous waterproofing provides superior water repellency due to its non-porous, petroleum-based nature. It is excellent for flat roofs, foundations, and underground structures, where continuous exposure to moisture is expected. The key reason for its superior resistance is its hydrophobic (water-repelling) nature, which prevents water absorption and penetration.

Breathability Differences Between Cementitious and Bituminous Waterproofing

Cementitious waterproofing is highly breathable while bituminous waterproofing has a lower breathability.

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.. 

Bituminous waterproofing has a lower breathability. It forms a completely sealed, non-permeable layer, preventing both water and vapor from passing through. This characteristic makes it effective for roofing and underground applications, but in enclosed spaces like basements, improper application can trap moisture, leading to condensation issues.

Flexibility Difference Between Cementitious and Bituminous Waterproofing

Cementitious waterproofing is not flexible while bituminous waterproofing is highly 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.

Bituminous waterproofing is more flexible compared to cementitious waterproofing. Bituminous waterproofing can withstand structural movements and temperature changes without cracking it due to its flexibility. The bituminous membrane flexibility depends on the polymer content in it. It allows to stretch and contract without losing adhesion. It helps to use bituminous waterproofing on roofs, bridges, and areas with thermal expansion.

Chemical Resistance Difference Between Cementitious and Bituminous Waterproofing

Cementitious waterproofing has a moderate chemical resistance while bituminous waterproofing has a superior chemical resistance.

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.

Bituminous waterproofing offers superior chemical resistance. Especially against salts, acids, and industrial pollutants. The hydrocarbon-based composition of bitumen makes it highly resistant to chemical corrosion, making it an excellent choice for industrial facilities, underground structures, and chemical storage areas. 

UV Resistance Difference Between Cementitious and Bituminous Waterproofing

Cementitious waterproofing has a higher UV resistance while bituminous waterproofing has a poor UV resistance.

Cementitious waterproofing is highly resistant to UV radiation due to its mineral-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.

Bituminous waterproofing has a poor UV resistance. When it is exposed to sunlight, it causes oxidation, brittleness, and surface cracking, reducing its lifespan over time. In order to improve UV protection, a protective layer like aluminum foil, gravel, or a UV-resistant coating is often applied over bituminous membranes. Without this protection, bituminous coatings deteriorate faster, leading to potential waterproofing failure.

Read our similar expert guide related to cementitious waterproofing

• Cementitious vs Polyurethane waterproofing
• Cementitious vs Epoxy waterproofing
• Bituminous vs Polyurethane waterproofing

Functional and Environmental Impact Comparisons Between Cementitious and Bituminous Waterproofing

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

What is Cementitious Waterproofing?

Cementitious waterproofing is a rigid, cement-based waterproofing system used to protect concrete structures from water penetration. It is composed of cement, sand, special additives such as marble dust or silica sand, lime,  ground salt, alum stone or calcium chloride. Polymer modifiers are also added to cementitious waterproofing to improve adhesion and flexibility to the substrate. Cementitious waterproofing can be applied as a liquid slurry or mortar to the substrate that bonds permanently with concrete surfaces.

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

What are the Advantages of Cementitious Waterproofing?

1. Easy to apply: Cementitious waterproofing does not require specialized equipment.
2. Excellent adhesion: Cementitious waterproofing bonds permanently with concrete, preventing water seepage.
3. Cementitious waterproofing is highly resistant to hydrostatic pressure
4. Cementitious waterproofing is non-toxic and safe for potable water
5. Cementitious waterproofing is UV resistant 

What are the Disadvantages of Cementitious Waterproofing?

1. Rigid and brittle: Cementitious waterproofing prone to crack even in small movement
2. Cementitious waterproofing has a limited flexibility
3. Cementitious waterproofing is not effective for dynamic surfaces
4. Cementitious waterproofing has a Moderate chemical resistance
5. Cementitious waterproofing requires multiple coats for higher protection

What is Bituminous Waterproofing?

Bituminous waterproofing membranes are water-dissolved, sticky, higher temperature sensitive, and have a higher viscosity and higher deformed at room temperature, black-colored, liquid, or semi-solid forms of asphalt that are derived from petroleum, used to prevent water leaking from basements, foundations, bathrooms, balconies, rooftops, slabs, and construction surfaces. 

What are the Advantages of Bituminous Waterproofing?

1. Bituminous waterproofing membranes are highly flexible
2. Bituminous waterproofing is an excellent water resistance
3. Bituminous waterproofing has strong chemical resistance
4. Bituminous waterproofing is adhered to the substrate tightly 
5. Bituminous waterproofing is resistant to root penetrations

What are the Disadvantages of Bituminous Waterproofing?

1. Poor UV resistant:  Bituminous waterproofing requires protective layers like aluminum coating or gravel.
2. Flammable: Some bituminous waterproofing requires heat protection due to fire risk
3. Environmental concerns: Bituminous waterproofing is less eco-friendly
4. Can soften under high temperatures: Bituminous waterproofing requires polymer modification for better stability
5. Seam issues in sheet membranes: Improper bituminous sheet membrane installation can lead to leaks at seams and overlaps.