As those who have followed the progress of Canada’s Greenest Home will know, we are taking the air tightness of this house very seriously. A great deal of thought has gone into ensuring construction details that make it easy to make an air tight enclosure, and just as much effort has gone into work on site to be sure we follow through on those details (much thanks to Graham Wise and our other diligent folders and tapers!).
As much as possible, we try to have the air tightness details addressed by building in a way that minimizes breaks in the air control layers and penetrations through these layers. However, there are places where joints and penetrations are impossible to prevent. To date, we’ve done our best to caulk and tape such areas with the best materials available to us.
That pallet of available materials just improved dramatically with our introduction to the line of tapes and membrane materials from Siga. These Swiss products are now imported into Canada by Herrmann’s Timber Frames in Curran, Ontario. As soon as we opened our first roll and began to apply it, we knew that air sealing for us was changed forever!
We are working largely with two products from Siga. The first is their exterior-grade tape, called Wigluv. This tape is outrageously sticky, and the tape material very flexible. We are using the Wigluv to tape our air control layer (a conventional Canadian housewrap) to our windows to provide a seal at this important junction.
The Wigluv takes some learning to apply cleanly, as it is so sticky that any errors in application result in tape stuck to fingers and any other surface that gets in the way! However, we quickly figured out how to fold the tape against the window to provide an excellent seal. Working from bottom to top of the window, we provide positive overlap at each tape seam. The flexibility of the tape means that the odd lump or bump in the application folds down completely, and if the corner is not perfectly ninety degrees, it will bend out of the way of the strapping we put on next. I feel like these will definitely be the most air tight windows we’ve ever installed.
The second product is similar, but meant for indoor applications, and is called Rissan. This tape is flexible enough to be very useful for sealing round holes in membranes, such as plumbing vent stacks and electrical conduits. Equally sticky as the Wigluv, the Rissan bonds to pipes, wires and conduits firmly and provide a great solution to these very hard-to-seal areas of the home. We will use the tape from both sides of the barrier wherever possible to further ensure a tight seal.
Whether or not these tapes have long-term lasting adhesion remains to be seen, but their test results are impressive and they far surpass anything that is widely available in the North American market.
For the time being, it’s too bad we have to import these tapes from Europe. Canada used to be a leader in the first wave of air tightness products for homes, but until somebody in North America starts making tapes of this quality, we’ll be using these Siga products to ensure our seams and joints are as air tight as possible.