A comprehensive ageing testing programme has been commissioned by DuPont Building Innovations from “SP Technical Research Institute of Sweden (Chemistry and Materials Technology – Polymer technology division)”
| The main factors impairing the effectiveness of underlays are temperature and UV radiation. Whether underlays are supplied as single layer or composite products, it is the functional layer which takes care of windproofing, waterproofing and vapour openness. Its thickness and quality are key to the durability and effectiveness of the underlay as a whole. |
Often on site, roofs or walls are not covered quickly or completely during the construction work and so an underlay remains exposed to the strong degrading action of direct UV. This can mean that the watertightness of the tested multi-layer is enormously reduced.
| Tyvek® underlays clearly demonstrate superior longterm performance. |
The results confirmed that the heat impact on the underlay’s degradation is less aggressive and immediate than the UV radiation impact, but the loss of watertightness is real, progressive and destructive.
| Tyvek® underlays clearly demonstrate superior long term performance. Even after 45 weeks, Tyvek® Supro was still functional and was not expected to fail soon. |
For more information on SP Technical Research Institute of Sweden 
