How CNS 8644 Helps Consumers Ensure the Quality of Waterproofing Materials
Choosing high-quality waterproofing materials is crucial to the long-term durability of buildings. Taiwan’s
CNS 8644 standard, developed with reference to international regulations and insights from industry experts, provides consumers and government agencies with a reliable benchmark for selecting waterproofing materials. This standard ensures that waterproofing systems can withstand environmental conditions over time, thereby improving overall building protection.
CNS 8644 Classification of Liquid-Applied Waterproofing Materials
CNS 8644 categorizes waterproofing materials based on their application—
roofing or
exterior walls—and further by material type:
- High-elongation polyurethane (PU)
- High-strength polyurethane (including polyurea)
- Acrylic (including elastomeric cement)
- Neoprene
- Bitumen
- Silicone-based coatings
Each material type must meet key performance indicators to ensure long-term reliability.
Key Performance Criteria for High-Quality Waterproofing Materials
- Tensile Strength
- Prevents cracking due to structural shifts (e.g., during earthquakes)
- Indicates the material’s ability to resist physical forces
- Elongation
- Allows flexibility with temperature changes and structural movement
- Reduces the risk of cracking and leakage over time
- Tear Strength
- Protects against damage during application or regular use
- Higher tear resistance reduces the risk of mechanical failure
- Heat Expansion/Contraction
- Ensures dimensional stability under high temperatures
- Ideal for rooftops and buildings in hot climates
- Weathering (Aging) Resistance
- Simulates long-term exposure to UV, acid rain, and moisture
- High durability reduces the need for frequent maintenance
- Aging Under Tension
- Tests stability under mechanical stress
- Suitable for high-stress applications (e.g., basements, bridges, high-rise buildings)
Comparison of Common Waterproofing Materials
The most commonly used waterproofing materials include
PU (polyurethane),
polyurea,
acrylic,
neoprene, and
bitumen—especially in rooftop and balcony applications.
Material Selection Guide
Polyurea
- Excellent tensile, tear, and weather resistance
- Best for high-stress, long-term protection
- Newer aliphatic polyurea (3rd generation) offers better UV resistance and weathering performance
- Typical high-performance system: primer + polyurethane/polyurea base + aliphatic polyurea topcoat
- Higher cost and more complex to install
Polyurethane (PU)
- Flexible and weather-resistant
- Easier to apply; suitable for rooftops and exterior walls
- Can be blended with polyurea for added strength
- Ideal for high-durability applications with a mid-to-high budget
Acrylic
- Affordable and easy to use
- Suitable for general waterproofing and DIY applications
- Less durable than other materials
Installation & Maintenance Considerations
- PU and polyurea systems can be exposed or topped with synthetic turf or stone, as they are not suitable for direct tile adhesion.
- Exposed waterproof layers are easier to maintain, allowing localized repairs without removing tiles or generating waste.
- For tile installation, proper interface treatment is recommended:
- Apply primer or bonding coat
- While still tacky, broadcast quartz sand to improve roughness and adhesion
- Allow to dry completely before tiling
Why CNS 8644 Matters
CNS 8644 provides a comprehensive benchmark for selecting waterproofing materials that offer
long-term protection and performance. By understanding the characteristics of each material, you can choose the best solution based on
budget, ease of installation, and durability.
To explore full testing methods and detailed specifications, visit
CNS Online for the complete version of the CNS 8644 standard.
Recommended Reading Topics (Click to explore)
- How to Choose High-Quality Waterproofing Materials
- How CNS 8644 Helps Regulate Waterproofing Material Standards
- Detailed Requirements of CNS 8644 — Roofing & Balcony Applications
- TPUCO’s CNS 8644-Compliant Waterproof Coatings
- Professional Contractors vs. DIY — Which Should You Choose?
- Why You Need Primer, Base Coat, and Top Coat in Waterproofing
- Real-World Waterproofing Case Studies and Success Stories
This article is based on international research, internal lab testing, and practical field experience. Variations due to proprietary formulas or methods by specific manufacturers are not covered here.
Have questions or need high-performance waterproofing solutions? We’re here to help.
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Link to TPUCO products:
Fast drying polyurethane coating:
https://www.taiwanpu.com/en/product/Fast-drying-polyurethane-coating