Torch-On SBS Underlay – Heavy Duty – Residential & Commercial Roofing

Product Overview

This Heavy Duty Torch-On SBS Underlay is supplied in a 16m² roll, providing a durable waterproofing base layer for flat and low-pitched roofing systems. Reinforced with a strong polyester core and modified with SBS elastomeric bitumen, this underlay ensures flexibility, dimensional stability, and long-term resistance to cracking. It serves as the essential first layer in multi-layer torch-on systems, creating a robust waterproofing foundation beneath mineral-finished cap sheets.

Features & Benefits

• SBS-modified bitumen: Enhances flexibility, impact resistance, and cold weather performance.
• Polyester reinforcement: Provides dimensional stability and strength under load.
• Waterproofing base: Acts as the foundation layer beneath cap sheets.
• Torch-on application: Creates a secure bond and continuous watertight layer.
• Versatile use: Suitable for both new build roofing and overlay refurbishment.
• High coverage: 16m² roll maximizes efficiency for medium to large roof areas.

Applications

• Flat roofing systems: Base layer in multi-layer torch-on bituminous systems.
• New builds: Provides initial waterproofing foundation beneath mineral cap sheets.
• Overlay projects: Suitable for refurbishing existing bituminous roofs.
• Commercial and industrial: Applied in large flat roof developments.
• Residential roofing: Used in garages, extensions, and garden buildings.

Installation Guidance

• Preparation: Ensure roof deck or existing surface is sound, dry, and secure.
• Torch-on method: Apply heat to the underside bitumen, bonding to the substrate or separating layer.
• Laps: Maintain minimum 75mm side laps and 100mm end laps for integrity.
• Ventilation: Where overlaying existing roofs, ensure trapped moisture is avoided.
• Safety: Observe hot works safety standards when using propane torches.

FAQ

• Q: Can this underlay be used for overlay projects?
  A: Yes, it is suitable for refurbishing existing bituminous roofs.
• Q: What is the recommended lap size?
  A: Maintain a minimum of 75mm side laps and 100mm end laps.
• Q: Is special equipment needed for installation?
  A: Yes, use a propane torch for the torch-on application method.