Reflective Sheathing / Decking – Roof Installation

Ask The Expert – Q & ACategory: Reflective FoilReflective Sheathing / Decking – Roof Installation
RIMA Expert Staff asked 4 years ago

Believe it or not I cannot find an answer to this question on the internet. Reflective sheathing/decking for a roof – although manufacturer guidelines states to install shiny side in, why? What happens if it is installed outward then felt and shingles on top of it? I cannot find what difference it makes.

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Best Answer
RIMA Expert Staff answered 4 years ago

When aluminum foil faces an air space it will reflect 97% of the heat rays directed toward it, or conversely, it will not emit more than 3% of the head that is conducted to it from the other side. When aluminum foil is in direct contact with another surface, (like shingles), it will become a direct conductor of heat. Having the aluminum foil surface in direct contact with the roof shingles will provide no thermal benefit whatsoever.