This photo is from my attic, looking straight down in-between the walls behind the faucet/showerhead-side of my bathroom. This bathroom is always cold & we've recently heard "noises" during the night from the attic emanating from this wall. I believe critters have made their way from below the house up this pipe into our attic to nest/poo. Being unfamiliar with this kind of interior work, should this gap in the wall be insulated? Should I put boards/chicken wire on both top/bottom of the gap to desway critters? Is this open spacing normal, due to this plumbing vent?
Help me Home-Improvers. You're my only hope!