Flexible for waterproofing. Part 1: Bituminous sheets for waterproofing of roofs. Determination of dimensional stability

This technical specification outlines the methodology for determining the dimensional stability of bitumen-based waterproofing sheets specifically designed for roof applications. It serves as a critical reference within the broader framework of flexible sheet materials used for waterproofing in construction. The document details the procedural steps required to assess how these sheets maintain their original dimensions under defined thermal conditions. By establishing a uniform test protocol, it ensures that manufacturers and testing laboratories can evaluate the performance of roofing products with consistency and reliability. The scope covers the preparation of test specimens, the environmental conditions necessary for the stability assessment, and the precise measurement techniques to quantify any deformation or shrinkage. This approach facilitates quality control and helps verify compliance with essential performance criteria for materials intended to protect building structures from water ingress.