Appraisal number: 938 (2017)
Date issued: 20 Dec 2017
Watertight Roof Underlay
Watertight Roof Underlay is a synthetic building underlay for use under roof claddings. The product consists of a micro-porous water-resistant polypropylene film laminated between two layers of spun-bonded polypropylene and is coloured grey.
Techno Insulation Brochure Version No.1. Wall Underlay, November 2017
Always refer to the Appraisal in full and the technical literature.