Tyvek® Reflex Provides Long Term Protection

Case Study
Case Study
Tyvek® Reflex provides long term protection

From an unfortunate situation, a further demonstration of superior resistance


In this period of uncertainty in the UK construction market, it is encouraging to know that some companies - manufacturers of building products and their distributors - place significant emphasis on the durability. DuPont Building Innovations, the division of DuPont responsible for the renowned DuPont™ Tyvek® range of products is one such manufacturer. Not only does the company’s innovative approach consistently develop new solutions and systems for the benefit of the market, but the resulting product range offers long term performance and peace of mind.

This has been proven on a number of occasions, but perhaps few more dramatically than on one construction site towards the end of 2010. The product in question is DuPont™ Tyvek® Reflex, the original low emissivity breather membrane for walls, which was installed in four timber frame houses in Burwell.

The membrane was supplied by SIL Bedford to Kingspan Potton (a long term user of DuPont™ Tyvek® Reflex) and factory fitted to the timber frame panels during manufacture in March 2008. Unfortunately the main contractor went into administration during the build, leaving the work incomplete and subsequently the membrane was left fully exposed to the elements and potential UV degradation for a period of 33 months.

As unfortunate as this situation was, it nevertheless offered an opportunity for DuPont to test the product under such extreme conditions. Samples of the exposed material were removed for examination by DuPont at its facility in Luxembourg provided the following results. 

Property Standard Unit

3480M at nominal view

North after 33 months UV

South after 33months UV

Watertightness Class
EN1928 with modifications EN13859-2




Water Column EN20811 m >2 2/2,2 1,6/1,8
Emissivity DuPont Luxembourg method N/5cm 0,15 0,18 0,18
Tensile MD
EN 12311-1 mod. EN13859-2
N/5cm 250 215 212
Tensile XD
EN 12311-1 mod. EN13859-2
  210 180




DuPont guarantees the functionality of DuPont™ Tyvek® Reflex on the basis that it is protected from UV exposure within 4 months of installation and tests have shown that the product will suffer no reduction in performance over this time. However, in this case, the recommended time period was clearly exceeded – and by over 800%!

These test results demonstrate that companies such as Kingspan Potton, when choosing a product with such proven reliability, can be confident in the long term performance of the membrane in terms of both energy efficiency and the protection of the structure, even when exposed to wind, rain and UV. The two most important criteria for a reflective breather membrane are

  • the emissivity value and hence the benefit to the structure’s u-value
  • protection against water ingression (304)


From the test results above, watertightness is unaffected, while the emissivity performance saw a drop of only 0.03. This is a significantly minimal reduction in performance, particularly when the considerable exposure time is taken into account and offers distributors, manufacturers, contractors and home owners the reassurance that when DuPont™ Tyvek® Reflex is installed to the manufacturer’s instructions the long term reliability of the product is guaranteed.

This example also illustrates how the product provides a structure with long term protection against all weather conditions. Over the preceding 33 months, the area of Burwell (and therefore the construction site in question) experienced the full range of UK climatic conditions without any damage being sustained by the membrane.