Two of the most common waterproof coatings used in construction are PU (polyurethane) and JS (polymer-cement). Both work. Both are proven. But they solve different problems, and choosing the wrong one for your application costs money and causes failures.
This guide breaks down the real differences so you can make the right choice for your project or your product line.
| Feature | PU Coating | JS Coating |
|---|---|---|
| Components | Single-component | Two-component (liquid + powder) |
| Elasticity | 300%+ elongation | 80-150% elongation |
| Heat Resistance | -20°C to +80°C | -10°C to +60°C |
| UV Resistance | Excellent | Moderate |
| Can Tile Over? | Needs bonding layer | Yes, directly |
| Best For | Roofs, exterior walls, foundations | Bathrooms, kitchens, balconies |
| VOC / Odor | Low (water-based) | Zero |
| Cost | Higher | Lower |
| Skill Level | Medium | Easy |
Use PU when the surface is exposed to weather. Roofs, exterior walls, terraces, foundations — anywhere that sees direct sun, rain, and temperature swings.
PU's 300%+ elongation is critical for exposed surfaces in the Middle East. A flat roof in Dubai can swing from 70°C in the afternoon to 25°C at night. That thermal cycling puts enormous stress on coatings. PU stretches and returns; JS cracks.
Use JS when you need to tile over the waterproof layer. JS coating bonds perfectly with tile adhesive — no additional bonding layer needed. This makes it the standard choice for interior wet areas.
JS is also cheaper per square meter and easier to apply — mix the two components, brush on, done. No special equipment or technique needed.
The most common mistake is using JS coating on exposed flat roofs because it's cheaper. This works fine in mild climates, but in the Middle East, JS on an exposed roof will crack within 1-2 summers. The thermal cycling exceeds its elongation capacity.
The reverse mistake — using PU under tiles in a bathroom — wastes money. PU costs more and doesn't bond as well with tile adhesive. JS is purpose-built for this application.
Rule of thumb: Exposed surface = PU. Under tiles = JS. Following this simple rule prevents 90% of application failures.
If you sell waterproof coatings in the Middle East, you need both in your product line:
Together, these three products cover 90% of waterproofing needs in residential and commercial construction.
JS coating is generally better for bathrooms because tiles can be applied directly over it without additional preparation. PU coating requires a separation layer before tiling. However, for bathrooms exposed to extreme temperature changes, PU offers better flexibility.
JS coating has a lower material cost per square meter, but PU coating lasts longer (8-10 years vs 5-8 years for JS in exposed conditions). For covered interior areas like bathrooms, JS offers the best value. For exposed roofs and terraces, PU provides better long-term cost efficiency.
Yes. A common professional approach is to use JS coating on interior wet areas (bathrooms, kitchens) and PU coating on exposed areas (roofs, terraces) within the same project. They serve different purposes and complement each other well.
Fansen manufactures both PU and JS coatings with formulas optimized for Middle East heat. One supplier, complete product line, simplified logistics.
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