TS EN 13970/A1

TS EN 13970/A1 is the A1 amendment to EN 13970 for flexible sheets used in waterproofing, focusing on bitumen water vapour control layers. It is tied to the terminology and characteristic framework used to define these products and describe the properties by which bitumen-based vapour control layers are identified and compared.

In general technical terms, vapour control layers are used in the building envelope to limit the amount of moisture migrating from the interior into the construction build-up. Bituminous flexible sheets function as membrane products that can provide continuity across a surface and work as part of a system at laps, joints, and interfaces. In this type of product family, the distinction between definition and characteristics matters because the intended function, material behaviour, and compatibility with surrounding layers all depend on those concepts.

Core concepts for bitumen vapour control layers

Within this standard family, “bitumen” indicates a bitumen-based binder phase, while “flexible sheet” refers to a roll or sheet membrane that can conform to the substrate during installation. Vapour control layers are commonly used in roofs and wall assemblies to help manage condensation risk. Their practical performance is associated with general technical properties such as resistance to vapour diffusion, mechanical strength, thickness, surface structure, and the installation system.

• The A1 document is an amendment to the EN 13970:2004 base standard, updating an existing framework rather than introducing a separate subject area.
• It addresses the definitions and characteristics of bitumen water vapour control layers.
• Standards of this kind support common terminology and technical comparison across product families.
• In practice, the subject is closely connected with building physics, moisture control, and layered roof or wall design.