Acrylic vs Polyurethane Waterproofing: What You Should Know?

Material Properties Comparison Between Acrylic and Polyurethane Waterproofing

These are the material composition, performance, durability, and environmental resistance comparisons between acrylic and polyurethane Waterproofing.

1. Acrylic waterproofing is a water-based polymer modified coating , while polyurethane is composed of synthetic polymers derived from a reaction between polyols and isocyanates.
2. Acrylic waterproofing has a lower water resistance than polyurethane waterproofing
3. Acrylic waterproofing is more breathable than polyurethane waterproofing
4. Acrylic waterproofing has a moderate flexibility, while polyurethane has a superior flexibility.
5. Acrylic waterproofing has a moderate chemical resistance , while polyurethane has a higher chemical resistance
6. Acrylic waterproofing has a moderate thermal stability , while polyurethane has an extremely high thermal stability
7. Acrylic waterproofing has better UV resistance than polyurethane waterproofing

Composition Differences between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing is a water-based polymer-modified coating , while polyurethane is composed of synthetic polymers derived from a reaction between polyols and isocyanates .

Acrylic waterproofing is a water-based, polymer-modified coating that is made from acrylic resins. Acrylic waterproofing consists of compounds such as acrylic polymer, water, fillers, pigments, additives, and preservatives.  Acrylic forms a highly water-resistant, UV-resistant, flexible protection layer on the substrate after it is applied. This is an environmentally friendly coating with low VOC.

Polyurethane waterproofing is composed of synthetic polymers derived from a reaction between polyols and isocyanates. It forms a seamless, super elongated elastomeric membrane when it is applied to the substrate.

Water Resistance Differences between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing has a lower water resistance than polyurethane waterproofing

Acrylic waterproofing has a moderate water resistance. Acrylic waterproofing membrane creates a protective barrier on the substrates that repels moisture but remains slightly permeable. The water resistance of this membrane depends on the number of coats applied and environmental conditions. Due to the moderate water resistance of the acrylic waterproofing membranes, it is highly recommended for the light to moderate water exposure areas.

Polyurethane waterproofing provides superior water resistance over time without any cracks or damage due to its elastic nature. It can withstand various weather conditions and even small structural movements.

These are the most commonly used 10 types of waterproofing membranes, which are used for building waterproofing. You should read all of the 10 Types of Waterproofing Membranes before you start your waterproofing project.

Breathability Differences between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing is more breathable than polyurethane waterproofing

Acrylic waterproofing is highly breathable. Acrylic waterproofing allows trapped moisture to escape the trapped moisture from the substrate. Higher breathability of the acrylic waterproofing reduces the risk of blistering and peeling the waterproofing membrane and making it suitable for areas prone to dampness.

Polyurethane waterproofing is less breathable than acrylic waterproofing due to its dense molecular structure. Polyurethane waterproofing forms an airtight seal that locks out moisture completely, which is beneficial for areas requiring total water exclusion. However, poor ventilation beneath the membrane can lead to trapped moisture issues, such as mold and mildew growth and blistering. To prevent these problems, the substrate should be prepared properly

Flexibility Differences between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing has a moderate flexibility, while polyurethane has a superior flexibility.

Acrylic waterproofing provides moderate flexibility. It helps to accommodate minor surface movements without cracking the waterproofing layer. Acrylic waterproofing’s elasticity depends on the thickness and reinforcement used for the mixture. Hence, acrylic waterproofing has a limited stretch range and should not be used in high-movement areas.

Polyurethane waterproofing offers superior flexibility due to its elastomeric nature. It can stretch and recover without losing its adhesion. Hence, polyurethane waterproofing is ideal for surfaces that is subjected to expansion and contraction over time. The high flexibility of the PU prevents cracks and failures in dynamic structures.

Chemical Resistance Difference between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing has a moderate chemical resistance , while polyurethane has a higher chemical resistance

Acrylic waterproofing has moderate chemical resistance. Hence, it is suitable for general outdoor and residential applications. Acrylic waterproofing can withstand mild acids, alkalis, and UV exposure, but prolonged exposure to harsh chemicals or industrial pollutants can degrade its performance over time.

While polyurethane waterproofing exhibits excellent chemical resistance, it also protects surfaces from oils, solvents, and aggressive chemicals. Its dense composition makes it suitable for industrial settings, chemical plants, and areas exposed to contaminants, ensuring long-term durability in harsh environments.

Temperature Stability Differences Between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing has a moderate thermal stability , while polyurethane has an extremely high thermal stability

Acrylic waterproofing has a moderate temperature stability range, but it can soften under extreme heat or become brittle in freezing conditions. Hence, acrylic waterproofing is suitable for temperate climates but may require additional protection in areas with severe temperature fluctuations to protect the layer from extreme temperatures.

While polyurethane waterproofing has exceptional temperature stability, it maintains flexibility and adhesion across a wide range of conditions. It resists thermal expansion and contraction, making it ideal for both hot and cold climates, ensuring long-lasting performance without cracking or degradation.

UV Resistance Differences Between Acrylic and Polyurethane Waterproofing

Acrylic waterproofing has better UV resistance than polyurethane waterproofing

Acrylic waterproofing has excellent UV resistance due to its water-based acrylic resins, which naturally reflect sunlight and prevent degradation. It resists yellowing, chalking, and surface breakdown. Hence acrylic waterproofing is ideal for exposed areas like terraces, roofs, and facades. Its UV stability helps maintain its durability and appearance over time.

While polyurethane waterproofing has lower UV resistance than acrylic waterproofing membrane. When the PU is exposed to sunlight, it can yellow, harden, or degrade due to UV light. As well as PU coating can be cracked or lose flexibility when it is exposed to UV light for a prolonged. In order to prevent this, PU is formulated with UV stabilizers.

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Functional and Environmental Comparisons Between Acrylic and Polyurethane Waterproofing

These are the mechanical strength, safety, environmental impact, and usability comparisons between acrylic and polyurethane Waterproofing