Inclination and the underlay membrane
Under bitumen shingles, an underlay membrane (Kerabit 700 UB, Kerabit 2200 UB or 2500 UB) is required. Shingles and strips dedicated for a specific purpose are available for eaves, ridges and other special applications.
Bitumen shingles can be laid directly on top of the underlay membrane, without allowing for any gap for ventilation. The minimum roof inclination is 1:5. Generally, the underlay membrane must meet the requirements set for the product category AKK2 (Kerabit 700 UB, Kerabit 2200 UB and 2500 UB). If the roof inclination is 1:4–1:5, or if the roof has a large number of valleys or other details, the use of underlay membranes corresponding to the product category AKK1 is recommended.
Instructions for use
Bitumen shingles are lightweight and easy to work with. The roofing can be laid on a substrate of tightly joined tongue-and-groove boards or building boards suitable for the purpose. The old roofing may be left in place, providing a substrate over which the underlay membrane can be laid. During storage, shingles must be protected from rain and exposure to sunlight.
Bitumen shingles are constructed of strong non-woven glass fibre reinforcement coated with modified bitumen. Slate or mineral granules on the top of shingles protect them from exposure to weather. On the underside of shingles, a layer of self-adhesive modified bitumen ensures a firm bondage between the shingles. Kerabit S+ bitumen shingles have a wavy shape.