Due to a slight mishap (dowels pulling out of drywall when relocating my shelf layout) I have to rebuild. I want to use something lighter than the heavy 3/4" wood panels that contributed to the mishap. In the past I have built a 2" thick lightweight box beam from 1/2" foam core poster board for part of the layout, which has proven to be sturdy and lightweight, but that stuff is quite expensive. I had good results building a beer keg cooling enclosure from foil-faced polyisocyanurate foam, so I am thinking of using a similar material. The foil facing on the 1" material buckles easily under bending pressure, so I found similar sheets with fiber glass reinforced facing that I hope will be sturdier: https://www.jm.com/en/building-insu...am-board---sheathing/r-panel-roof-insulation/ Does anybody have experience with this material? I special ordered a 2" thick sheet from Menards - apparently it is not popular enough for roofing applications in this area to be kept in stock. My plan is to support 8' wide 2' deep panels on a few (three?) wall support arms. The layout is L-shaped, consisting of two panels with 6" extensions for turnaround loops (N scale).