I have a question as to what this white stuff is. It is dry and chalky. It only appears near the opening to the garage. The photo is looking up into the pulldown stair opening. It is an attic over the attached garage. In the garage are an electric water heater, washer and dryer (also electric) and an air handler.
I included a photo and a video but I am not sure if they have uploaded properly.
FYI-it really doesn’t taste like anything
Thanks guys. I hope Ryan is wrong cause this is my house! I have to say it seems overspray makes sense cause there is knock-down texture on the garage ceiling and I just went to look again and the same overspray is evident where the return duct penetrates the ceiling.