I watched a video from https://www.stonecoatcountertops.com/shower-epoxy-page and they used foam board, and put an epoxy on top to mimic a marble slab for the shower wall. It looked really good but my question is, is foam board a good alternative for walls? My fear is it might me too brittle if something were to hit it and crush it easily. Has anyone seen or used this method? I was thinking maybe using the same method but using plywood instead. Any help would be greatly appreciated.