Closed cell here.
I would also look at adding some striations or a rib roll profile if you are worried about it.
Most oil canning issues stem from decking issues.
I have read Todd Miller's comments about using foam backer rods in the center of a metal roof panel to help with oil canning. I would like to try 3/8 inch foam rods, but I am not sure which ones I should buy. Local masonry supplier sells both SOF (soft) Rods and harder closed foam rods. Which rods are people referring to in the forms?
Also, I am in Texas and metal roofs get very hot. Will the foam rods melt?
Thanks
