PUF – Polyurethane Foam – Complete Technical Overview

What is PUF? 

PUF is a closed-cell, spray-applied foam produced by the reaction of polyol and isocyanate under controlled pressure and temperature. It’s primarily used for thermal insulation and lightweight waterproofing support.

Key Advantages 

1. High Thermal Resistance: Low thermal conductivity (0.020–0.028 W/m·K), excellent for insulation.

2. Closed-Cell Structure: Prevents water absorption and penetration.

3. Lightweight: Minimal load on structure (40–50 kg/m³ density typical for roofing). 

4. Seamless Application: No joints, reducing leakage risk. 5. Excellent Adhesion: Bonds to concrete, metal, tiles, wood, and more.

Application Process 

1. Surface Preparation 

• o Remove loose particles, grease, and dust. 
• o Surface should be dry and stable.

2. Spray Application 

• o PUF chemicals (Part A – isocyanate, Part B – polyol blend) are sprayed via high-pressure machine. 
• o Foam expands rapidly (30–40 times its liquid volume) and sets within seconds. 
• o Applied in layers to achieve required thickness (commonly 25–50 mm for roofs).

3. Protective Coating 

• o PUF is UV-sensitive and must be coated with polyurea or elastomeric coating for protection.

Common Applications 

• Roof insulation (industrial, commercial, residential)

 • Cold storage & refrigerated spaces 

• Pipeline and duct insulation

 • Building envelope thermal control 

• Under-deck insulation in factories