The IKO Standard SBS Torch-On Underlay is a fully bonded, torch-applied roofing membrane. It is glass fibre-reinforced and manufactured from SBS-modified bitumen. The membrane features a sanded upper surface and a thermofusible film underside. The IKO SBS Standard Torch-On Underlay is intended for use as an underlay or intermediate layer within a bituminous built-up roofing system.