When it comes to sustainability, cost-efficiency and occupier comfort – not to mention compliance with the latest regulations – recognition of the benefits of airtight construction is growing.
Achieving a high level of airtightness may sound complicated, even unattainable. But with the right products and proper guidance, extraordinary outcomes can be achieved.
A recent ‘passive house’ demonstration at BRE (Building Research Establishment) brought together key DuPont membranes, AVCLs, tapes, sealants and the correct installation methods, which yielded impressive results.
The products were fitted to a specially built structure, with great care taken to correctly seal at laps and penetrations, and in all corners, curves and awkward spaces. Tyvek® Supro was installed on the roof, Tyvek® HouseWrap (and in a later phase, the latest low emissivity Tyvek® membrane) on the exterior walls, and AirGuard® Control AVCL on the interior walls. Tyvek® tapes were used throughout, including the newly launched Tyvek® FlexWrap EZ tape, to seal around windows, doors, rafters and floors. In short, a complete system to ensure optimum results.
A blower door was fitted and the structure pressurised to the industry standard 50Pa. Results were recorded after each stage of application and the final figure came in at 0.12 m3/hr/m2 @50Pa (0.24 ACH). This is well below the exacting Passivhaus standard of 0.6 ACH, which is equivalent to around 0.3 m3/hr/m2 @ 50Pa.
Even the BRE was impressed, saying the testing showed the importance of maintaining an airtight barrier around the test building to prevent unintended air infiltration/exfiltration. The DuPont™ Tyvek® and AirGuard® membranes and tapes provided an almost complete air tight seal around the walls and roof of the test building, which significantly exceeded the air tightness requirements of the Passivhaus standard for low energy buildings.
A vital lesson, both from the BRE exercise and experience in the field, is that while airtightness can be straightforward to achieve using the right products and systems, there can be no weak link in the chain. A reduction of specification quality at any aspect of the envelope, a key step or process missed, or any careless or incorrect installation and the results will be as disappointing as the waste of time or money. There is simply no substitute for quality and expertise, and cutting corners – or failing to seal them properly – just doesn’t work. Furthermore, even with the best products and the best will in the world, those ‘hard to reach’ areas will also need special attention.
Meeting the increasing demand for airtightness in small or large scale projects is critical to a successful project as well as a contractor’s reputation. Complicated? It doesn’t need to be. There’s a simple solution: work with a proven system of fully tested products that are both innovative and proven over time – and the expert team behind them.
Tyvek® Supro, Tyvek® HouseWrap, AirGuard® Control (AVCL), and Tyvek® tapes including the newly launched Tyvek® FlexWrap tape are available from CCF branches.
For more information on DuPont™ Tyvek® please visit: www.construction.tyvek.co.uk