From Klober
Sepa Light is a three-layer non-breathable roof underlay for ventilated pitched roofs. The high-resistance membrane is a strong lightweight alternative to traditional 1F felt, with high tensile and nail tear strength. Area of application Suitable for use on ventilated pitched roofs. All wind zones with taped headlap. Wind zones 1-2 with batterned headlap. Key Features Strong lightweight alternative to traditional 1F felt. Absorbent inner layer as recommended in BS 5250. High tensile and nail tear strength.