Corotop Blue 1.5mtr x 50mtr Breathable Membrane 140gsm

High-performance three-layer breathable roofing membrane designed for use as an underlay on pitched roofs. Corotop 140gsm provides an effective water-resistant barrier beneath tiles or slates while allowing water vapour to escape, helping to protect insulation and maintain a healthy roof structure.

With a robust 140g/m² grammage, this membrane offers excellent mechanical strength and resistance to damage during installation and in service. Suitable for both fully supported and unsupported (open rafter) roof constructions, it delivers reliable performance in a wide range of pitched roof applications.

Key Benefits

• High vapour permeability – Allows the roof to breathe while remaining watertight (W1 rating).
• Strong 140gsm construction – Enhanced mechanical resistance for easier handling and greater durability on site.
• Protects insulation – Helps prevent moisture from reaching thermal insulation and reduces heat loss.
• UV and temperature resistant – Suitable for temporary exposure during the construction phase.
• Versatile application – Ideal for use under concrete tiles, clay tiles, metal roofing and other common coverings.
• Three-layer design – Combines strength, flexibility and long-term weather resistance.
• Certified performance – Meets relevant standards for pitched roof underlays.

Typical Specifications

• Weight: 140 g/m²
• Type: Three-layer polypropylene breather membrane
• Watertightness: W1
• Vapour permeability (Sd): Approx. 0.02 m
• Suitable for: Pitched roofs (supported or unsupported)

Ideal for roofers and builders seeking a reliable, high-quality breather membrane that balances strength, breathability and ease of installation. A trusted choice for both new builds and re-roofing projects.

Always install in accordance with the manufacturer’s guidelines, BS 5534 and current building regulations. Ensure correct overlaps, fixing and detailing for long-term performance.