Polymer-Modified Cementitious (JS) Waterproof Coating

Product Overview

Polymer-Modified Cementitious Waterproof Coating (commonly known as JS Waterproof Coating) is a liquid-powder type, water-based waterproofing system. It is formulated by blending high-quality polymer emulsions — such as acrylate, vinyl acetate-ethylene (VAE), and styrene-butadiene (SBR) — with Portland cement, graded fillers, and functional additives. Upon mixing and application, the coating cures via a dual mechanism: physical water evaporation followed by chemical cement hydration and polymer film formation.

The result is a continuous, flexible, seamless waterproofing membrane that combines the elasticity of polymers with the strength and durability of cement. This unique polymer-cement composite bridges hairline cracks, accommodates minor substrate movement, and provides excellent long-term protection for concrete, mortar, and masonry surfaces — without the need for organic solvents or open flames.

Designed for non-exposed and lightly-exposed applications, this environmentally friendly coating meets Type I performance requirements per JC/T 894 and GB/T 23445 standards. It has been rigorously tested for heat aging (80°C, 168 h), alkali resistance, acid resistance (2% H₂SO₄), and 1,000-hour artificial weathering — retaining ≥80% tensile strength and ≥450% elongation under all test conditions.

Key Features & Competitive Advantages

1. Polymer-Cement System
Liquid polymer emulsion plus powder cement — simple on-site mixing in a 1:1 ratio (or as specified). No weighing errors, no pot-life panic. This dual-component design ensures consistent film quality from batch to batch.

2. Water-Based — Low VOC, Environmentally Safe
Zero organic solvents. Compliant with green building standards and indoor air quality regulations. Safe for confined-space application in basements, bathrooms, and kitchens. No fire hazard during storage or construction.

3. Flexible, Seamless Membrane
Elongation ≥500% at break — the cured membrane bridges substrate hairline cracks up to 0.3 mm and accommodates minor structural movement without rupturing. Forms a continuous, joint-free waterproofing layer that eliminates the weak points of sheet membranes.
4. Dual-Curing Mechanism for Rapid Through-Dry
Surface-dry within 12 hours, hard-dry within 24 hours. Physical drying by water evaporation is followed by chemical cement hydration — delivering rapid film formation and early water resistance.
5. Superior Adhesion to Mineral Substrates
Bond strength ≥1.0 MPa to concrete, mortar, brick, and cement-based substrates. No separate primer required — the polymer content ensures a chemical-mechanical bond that resists delamination even in damp conditions.
6. Proven Durability Across Harsh Conditions
After 168 hours at 80°C, 80% tensile strength retained. After 168 hours in 2% H₂SO₄ or saturated Ca(OH)₂, 80% tensile strength retained with ≥450% elongation. After 1,000-hour artificial weathering, no cracks or deformation.
7. Excellent Low-Temperature Flexibility
No cracking at −35°C under bending test — suitable for cold-climate regions. After heat aging, maintains no-crack performance at −30°C — retaining flexibility even after prolonged thermal stress.

Technical Specifications (Type I)

Per JC/T 894 and GB/T 23445 — Polymer-Modified Cementitious Waterproof Coating Type I

Typical Applications

1. Non-Exposed Roof Waterproofing
Ideal for flat and sloped concrete roofs where the waterproofing layer is protected by tiles, screed, or thermal insulation. The flexible membrane accommodates thermal expansion and contraction without cracking.
2. Underground & Basement Works
Applied on basement retaining walls and floor slabs to prevent groundwater ingress. The alkaline environment of concrete enhances the cement hydration curing, producing a strong chemical bond.
3. Bathrooms, Kitchens & Wet Areas
Water-based, low-VOC formulation makes it safe for interior wet areas. Excellent adhesion to cement-based substrates ensures long-term performance behind tiles and under screeds.
4. Balconies & Terraces
Applied under tile finishes on exterior balconies and terraces. The ≥500% elongation absorbs structural movement, preventing tile debonding and water leakage.
5. Swimming Pools & Water Tanks
Suitable for non-immersion or light-immersion applications. The low water absorption (≤5.0%) ensures minimal swelling. Use with protective tile or render finish for full immersion conditions.
6.Complex-Structure Waterproofing
Brushes, rolls, or trowels easily around pipe penetrations, corners, coves, and irregular shapes where sheet membranes are impractical. The liquid-applied nature ensures 100% coverage of complex details.

Frequently Asked Questions

Q1: What is the minimum order quantity (MOQ)?
Our standard MOQ is 500 sets (liquid + powder combined). We support trial orders of 100 sets for new customers. Custom packaging options are available for orders above 3 tonnes.
Q2: Can I get a free sample?
Yes. We provide 1–2 kg samples free of charge. You only need to cover the express freight. Samples are dispatched within 3 working days after confirmation. Test reports are included with every sample shipment.
Q3: What is the shelf life and storage requirement?
Shelf life is 6 months for the liquid component and 12 months for the powder component when stored in original, unopened packaging at 5°C–35°C, away from direct sunlight and moisture. Do not freeze the liquid component.
Q4: Does this product have relevant certifications?
Yes. Our JS waterproof coating is tested per JC/T 894 and GB/T 23445 Type I standards. Third-party testing reports from accredited laboratories are available upon request. We can also support CE marking and other international certification requirements for volume orders.
Q5: Do you offer OEM / private-label services?
Absolutely. We offer full OEM and private-label services including custom packaging design, multilingual labeling, and technical data sheet (TDS) customization. Minimum order for private-label is 5 tonnes.