Is a foil-faced OSB roof deck worth it?
bsandersga
| Posted in Energy Efficiency and Durability on
My framer suggested we use foil-faced OSB for the roof deck, which we did. But, knowing that a reflective surface is effective mostly when there is an air space next to it, I was wondering if foil-faced OSB is worth it. When used for roof decking the foil facing would be to the inside of the attic and it would seem that it would be ineffective in reflecting heat away from the house.
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Replies
Robert,
Shiny foil is a low-e surface. That means that it doesn't emit as much radiant heat as a dull, black surface. If the foil is facing an air space, then the sheathing will emit less radiant heat than ordinary sheathing that isn't shiny. In other words, it works.
Foil-faced roof sheathing makes sense for new construction in hot climates, especially if your home has HVAC equipment or ductwork in the attic. If you don't have any ductwork or HVAC equipment in the attic, and if you have done a good job of air-sealing your ceiling, and if you have thick insulation on your attic floor, then it doesn't really matter very much whether you use ordinary roof sheathing or foil-faced sheathing.
Thanks, I live in Athens, Georgia and it looks like builders in this area are going with foil-faced OSB for roofing.