They are 16 gauge, affixed using stainless flat head screws to 3/4 exterior grade plywood battens spaced about 16" apart. The joints between panels are an 1/4" gap, coupled with gaps at the top and bottom, allowing for air flow behind the metal. The weather barrier is suitable for high temperature.

--also, the edges aren't hemmed. The corner is a lightweight 3x3 steel angle.

wow! thank you so much!!!!