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Here is something that I have always wondered about intensely for years but never had the forum to ask: Since asphalt-based and asphalt impregnated products (read:roofing materials)are such effective heat sinks, why don’t we prevent the structures that they are installed upon from transferring that heat into the attic-and inevitably, through conduction, into living spaces- by installing a layer of foil-faced rigid insulation first?
I have always wondered what was stopping me from doing this on a smaller project just to find out. But it seemed that the conventions are so standard; 15 pound felt on the deck, maybe some buttons rather than those staples, then a standard 25 year three-tab or a dimensional shingle. You will get tight roof sure enough, but suffice it to say that you are guaranteed to get a hot attic. But if one were to install, say, a 3/4 inch layer of double-sided foil-faced styrofoam, would that be enough of a thermal break? Or would there be concerns of the roof not “bonding to the structure?” I would love to hear some thoughts on this.
Regards,
L. Hunter.
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I have replaced roofs that were nailed onto insulation like this. They failed prematurely, and provided an open invitation for birds, animals and insects to nest, and nails to pull.
Maybe that's one reason?
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Here is something that I have always wondered about intensely for years but never had the forum to ask: Since asphalt-based and asphalt impregnated products (read:roofing materials)are such effective heat sinks, why don't we prevent the structures that they are installed upon from transferring that heat into the attic-and inevitably, through conduction, into living spaces- by installing a layer of foil-faced rigid insulation first?
I have always wondered what was stopping me from doing this on a smaller project just to find out. But it seemed that the conventions are so standard; 15 pound felt on the deck, maybe some buttons rather than those staples, then a standard 25 year three-tab or a dimensional shingle. You will get tight roof sure enough, but suffice it to say that you are guaranteed to get a hot attic. But if one were to install, say, a 3/4 inch layer of double-sided foil-faced styrofoam, would that be enough of a thermal break? Or would there be concerns of the roof not "bonding to the structure?" I would love to hear some thoughts on this.
Regards,
L. Hunter.