From IKO
IKO Perforated Sand Underlay is a perforated venting underlay which is sand finished on both surfaces. This product is loose laid to provide an economical, controlled partial bond to a substrate, when the subsequent layer is fully bonded in hot bitumen.Features and Benefits Formerly BS 747 Type 3H Roll Coverage: 20m2 British Standard glass-fibre based Economic roofing materials Sector of Application: Flat Product Type: Bituminous Membrane Type: Underlay Colour: Black Product Finish: Sand Installation Method: Loose Laid Project Type: Commercial Small, Domestic Large, Domestic Medium, Domestic Small