I see this issue has come up before but all the threads I found are closed. I have a 1979 ranch home in Wisconsin. I purchased the home in 2012. One of the first things I did was have an insulator come over and analyze the amount of insulation in my attic. He determined I had a lot of infiltration around canned lights, chimney, bathroom fan exhaust, and at the tops of the framed walls. He sealed all of those points and then added more insulation. I now have the original blown in, batt insulation over that, and now more blown in on top of that. He also added expanding foam type insulation in all the sill boxes in the basement. Ever since this has been done, I am experiencing a popping and cracking noise coming from my ceiling drywall whenever my furnace is running. If my furnace is only calling for 1° temperature increase, it's not too bad. But the longer it runs, the more popping and cracking occurs. The worst is when the furnace is running, and an exterior door is opened suddenly. That results in a burst of popping. A second attempt does not produce that same burst. It's as if opening the exterior door temporarily equalizes the pressure between the exterior and the interior of the house. I have experimented with just running the blower, and do not have any popping or cracking at that time. I recently had an HVAC person over to investigate, and he suggested bringing outside air into the cold air return which would help increase the pressure inside my home. That did not help. I have read about something called "trust uplift" and thought that perhaps this was my problem. However, I have the old style rafters and not trusses. I am not sure if this same phenomenon occurs with rafters. The bottom chord of my rafters are however buried beneath a large amount of insulation and likely stay close to interior house temperature, whereas the rafter members of that form the roof are exposed to extreme cold. I have had little physical damage appear, so I am not certain if my rafters are actually bowing in the middle. I don't have any other reason to believe they are. My ceiling does not have any signs of sagging anywhere. However, if I stand on a ladder, and Press upward with a good amount of force on my ceiling, I can reproduce the popping and cracking sound. I am not sure if I am flexing the rafter? Or the drywall up to the rafter. There is really no noticeable movement when I push on it. It seems like sealing up all the infiltration points on canned lights and other penetrations has caused my ceiling to flex up or down with pressure differences, whereas in the past, there was enough leakage which helped to equalize that pressure. At this point I am at a loss. No one seems to know what my issue is. I have Googled the heck out of this and have found nothing quite the same.

Well, I'm posting via phone and see no way to attach a photo. Guess I'll have to transfer photos to computer to do this.