Icopal Anderson VBL Venting Base Layer

The Icopal Anderson VBL Venting Base Layer is a perforated bituminous membrane designed to act as a base sheet within high-performance built-up roofing systems. Manufactured on a reinforced glass fibre carrier, the sheet is precision-perforated with 25 mm holes staggered at 75 mm intervals, allowing partial bonding to the substrate and effective venting of trapped moisture.

This layer is installed loose-laid and spot-bonded by torch application, forming a stable platform for subsequent waterproofing layers while reducing the risk of blistering or trapped vapour within the roof build-up.

Key Features

• Dual-sided bitumen coating for reliable performance
• Fine silica sand finish to improve handling and application
• Perforated reinforcement for controlled partial bonding and moisture release
• Compatible with most building materials (not recommended for use with solvent-based hydrocarbons)
• Supplied in 20 m x 1 m rolls
• Thickness: 4.0 mm | Roll weight: approx. 30 kg

Certifications & Standards

• Complies with BS 8747:2007 for reinforced bituminous membranes
• Manufactured under ISO 9001 quality management systems
• Produced to ISO 14001 environmental standards
• Supplied on pallets and heat-shrink wrapped for protection in transit

Application Guidance

• Substrate must be clean, dry, and free from dust or debris
• Membrane is loose-laid, then lightly bonded to the substrate by torch-on technique
• Overlaid with a compatible underlay or waterproofing membrane, which is torch-bonded into place

Storage & Handling

• Store rolls upright in a cool, dry, and shaded environment
• Protect from direct sunlight and contact with solvents
• Delivered shrink-wrapped on wooden pallets for secure handling and storage

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