IKO ULTRA H-A Underlay is polyester-reinforced bitumen membrane used within a built-up roofing system.
The membrane is coated on both sides with self-adhesive bitumen, SBS elastomeric coating. A fine mineral upper surface with a 75mm release film selvedge facilitates rapid installation of lap joints.
The underside has a self-adhesive bitumen coating that provides a 40% partial bond, allowing vapour dispersion between the membrane and substrate. The self-adhesive coating is protected by a release film.
The IKO ULTRA H-A Underlay is used as a partially bonded underlay within a built-up roofing specification system. It is to be used only for main flat roof areas and roof pitches up to 5° if reliant on adhesion alone.
For roof pitches over 5°, this underlay should also be mechanically fastened in accordance with BS8217 Table 5 or the IKO specification documents.
The unique self-adhesive profile of the IKO ULTRA H-A Underlay allows for a partial bond to be achieved to the substrate, therefore, reducing the risk of blistering from any trapped vapour.
The IKO ULTRA H-A Underlay has a 75mm selvedge lap with protective release film to the upper surface, and a 75mm wide selvedge lap to the corresponding underside to facilitate rapid sealing of the side laps.
