Jon Davies
February 15, 2016
Europe
Compatibility
and
Adhesion
of
Wet
Seals
and
Sill
Tapes
To help deal with the issue of sealants not bonding to substrates, pro clima will be offering a foil tape for window and door openings.
We from pro clima have been working with Sika, Tremco, and Bostik on this matter and have conducted several tests. While dealing with all three companies, it became apparent that there is a wider issue in the industry that no one has addressed until now. Seemingly, there have been significant issues regarding the plasticiser migration with bitumen-based tapes (compatibility issue) and sealants not bonding to substrates (adhesion issue).
While there is no compatibility issue with pro clima’s sill tape as it is free of bitumen, there is an adhesion issue with the very top layer — a thin polyethylene foil that acts like a bond breaker, and therefore there was no sign-off from any sealant supplier in the New Zealand market. To overcome this issue we engaged with current suppliers of foil backed tape, but they will not guarantee the adhesion of their foil tape to any substrates. As a result, there was no system in the New Zealand market that provided any guarantees.
International best practice is not to use wet sealants but to tape the window/door frames to the openings. Our pro clima CONTEGA® IQ is one option. With this option, you would normally not need any sill tape; however, this will not comply with the current requirements of the New Zealand Building Code. You might have seen the new Smartfit Window system from FWDS. This concept is one step towards eliminating sill tapes.
Coming back to the current issue, the sealant suppliers have also told us that they have issues bonding to standard wall underlays due to the water-repellent coatings. As an intermediate solution (before we see the industry change to taping the windows and doors into the openings), we will offer a pro clima foil tape, which will be available within the next few weeks.
We from pro clima will be able to sign off on the adhesion of the new pro clima foil tape to any substrate within the window and door opening. The sealant providers will then sign off on the adhesion of their wet sealants to the surface of our foil tape. This will provide a system with guarantees for the window and door installers.
From our end, we will try to reduce the costs of the tape as much as possible in the market to ensure this does not add significant expense.
The main advantage of this new pro clima foil tape is that it can be applied around the entire window and door opening on any substrate and provides a surface for adequate adhesion of wet sealants.
Attached you will find sign off from all three companies on the new foil tape, Tescon® Adhiso WS:
Inadequate Airtightness
A thermally insulated, airtight building envelope plays a major role in determining how comfortable and pleasant an indoor environment is for us and how well we can work, learn or relax there. The air temperature has the strongest effect on our perception of comfort level: a temperature range of between 20 °C and 23 °C in homes is regarded as comfortable in winter, while temperatures of up to 26 °C are perceived as pleasant in summer. In this context, airtightness has a crucial influence on the effectiveness of thermal protection in both winter and summer.
