Guest User
9/3/2001
We recently purchased a 20 yr old log home in an area that is subject to extreme cold (50-60 degrees below zero). The current roof is two layers of polyurethane foam that is growing 3 foot willow trees in depressions created by squirrels. The surface is lumpy. We want a metal roof but worry that the foam would have to be completely removed. Could a purlin substructure over the polyurethane support a metal roof in arctic conditions?
Todd Miller
Classic Products, Inc.
9/3/2001
Hello! I have worked in the past with a couple of installations over sprayed polyurethane foam. However, I really feel uncomfortable trying to give you a definitive answer. My suggestion is that you contact a few of the metal roofing manufacturers and see if they can't direct you to experienced contractors in your area who could inspect the roof, confer back with the manufacturer, and bring you a solution. There are numerous issues here including what's underneath the foam, how thick the foam is, whether it can be fastened through, what the roof pitch is, how the structure is ventilated, whether the structure can handle the weight of a new roof and support system on top of the foam, etc., etc. To answer your basic question, yes, there are metal roofs that could be installed over purlins even in your cold conditions. However, again, I do not want to give you a definitive answer without knowing more about your exact application. Good luck.
Allan Reid
Dura-Loc Roofing Systems, Inc.
9/4/2001
It sounds as if you have a sprayed in place foam roof that was probably installed over an existing roof of some type. Although there are metal roof systems like ours that install on purlins one needs to be sure that the substructure is in good condition to attach the new roof. Additionally, it will be very difficult to level it up. If the roof is too steep and the foam too thick care must be taken that the fasteners do dot roll and allow the entire new roof syatem to shift or slide with the excessive weight of the snow. In summary one would need more details to best answer the questions and reccomment chosing a product type then manufacturer to discuss the details with.
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