I have Warm and Natural over insulation board, too. DSIL put 2 pieces together on a frame and I covered it. I have it hanging on a blank wall. Had W&N on for 15 years but we moved and it got real dirty so we put new W&N on and it is now hanging on my wall again. If the place your curtain is has tracks for a sliding door or if it had doors on hinges, maybe you could use the insulation as doors in place of the curtain.