It is designed for use as a type of underlay on roofs with tiles,slates or steel tiles.This underlay can be also used to provide extra security under tiles when sub-roof sheets are used.The edges have been reinforced in order to boost its tear resistance,improve the nail holds and enable the product to withstand rough treatment. It has a glass fiber core that has been impregnated with bitumen.The core is coated on both sides with stabilised bitumen and the surface is coated with fine slate granules.The edge of this underlay has been reinforced with polypropylene felt to provide excellent tear resistance and good purchase for nails.  Specification:  1/,Weight/m2:550g,750gr,1200g,1500g.  2/,Roll size:1x20m,1x30m.  3/,Special size can be produced as requirement.