I’ve read about the idea of attaching a radiant barrier to the underside of the rafters. I have vaulted ceilings that will have a 1″ ventilation space just below the roof sheathing followed by foam.
Can I install the radiant barrier below the foam? Can anyone suggest a product to use?
Thanks!
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I've read about the idea of attaching a radiant barrier to the underside of the rafters. I have vaulted ceilings that will have a 1" ventilation space just below the roof sheathing followed by foam.
Can I install the radiant barrier below the foam? Can anyone suggest a product to use?
Thanks!
Are you talking about a radiant barrier between the roof and the foam? If the foam is already in place, it's too late because there's no way to put the barrier in the right place in your vaulted ceiling's rafter bays. The radiant barrier needs to be the layer facing the "hot" side, with an air gap between it and the source of radiation. Putting it on the underside of the foam would be pointless unless you're trying to keep heat in your space, in which case you'd need to fur out between the radiant barrier "mirror" layer and the finished ceiling material.
In my case the foam's not in yet and I need to have the code-required 2.5" of vent space, which eats a lot of my rafter bay that I'd rather fill with Icynene. But fighting the code here is pointless. I'm planning to use 1/2" or 1" insulating sheathing with a foil facing as my Icynene dam/radiant barrier layer, then fur out my rafters to give extra depth for icynene. This type of insulating sheathing product is not used in my area commonly so I'm having a bit of a hard time finding a suitable product. If anyone could recommend a brand name I'd be grateful.