Internal Airtightness

Effective Internal Airtightness and Thermal Insulation

Under the new European Energy Performance of Buildings directive, buildings need to be more energy-efficient than ever. The aim is to create airtight, condensation-free structures that combine thermal efficiency with comfort.

Why Is Airtightness So Important?

Although convective heat loss is not usually highlighted in standard U-value calculations, it is still a significant cause of energy loss and carbon emissions. So by limiting the leakage of heated/conditioned air from buildings, you can reduce energy consumption and costs noticeably.

Uncontrolled air leakage occurs through gaps between and around insulation layers and through hairline cracks in plasterboard linings. These invariably occur during the building drying-out process, but are also caused by settlement and thermal movement over the life of the building. Any layer in the building envelope where total continuity is not achieved is a potential weak point.

Vapour control layers suitable for roofs, walls and floors help to reduce convective heat losses but also provide highly engineered vapour control for breathing systems. When installed continuously with all laps and penetrations sealed, a vapour control layer will provide effective condensation control and airtightness for all building types.

AirGuard® air and vapour control layers (AVCLs) & Tyvek® Accessories

DuPont™ AirGuard® air and vapour control layers (AVCLs) can play a key role in improving thermal insulation effectiveness, to help you to achieve these goals sustainably. When installed correctly with all laps and penetrations sealed, AirGuard® AVCLs improve internal airtightness in all building types by helping to combat convective heat loss – i.e., the uncontrolled leakage of air from inside the structure to the outside. They also provide effective condensation control to keep insulation and walls reliably and durably dry.

DuPont™ AirGuard® air and vapour control layers (AVCLs) and adhesive tapes can help you to seal these gaps and improve the internal airtightness of your building. They are fully compatible with our Tyvek® breather membranes, and engineered for long-term performance and durability.  

Tyvek® AirGuard® Smart is a recent development that goes a step further by adapting its vapour permeability automatically when humidity levels change. It was specifically developed for all types of new build, but is highly recommended for renovation projects that involve above-rafter insulation, too.