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.

 

Where are your heat registers? In the ceiling or in the walls?

 

Welcome to the forums.

Yes.... old threads are closed as they should be. We here at DIY keep them in a searchable archive where they can always be read.

Each problem is somewhat unique and shouldn't be posted to an old thread. If you want to bring attention to that thread in this thread..... copy that page link and post it here in your text.

 

Heat registers are at floor level. Some come directly up through the floor with grilles, and others are at the baseboards.

 

Crack a window open an inch in a room where the noise is bad or in every room and see if that changes the noises. Operate the system that way as long as you can stand it, to observe any changes. That would tell you it's something to do with the air pressure being created by the unit.

 

Just tried it. Cracked the window a significant amount while the furnace was running. Still experienced ceiling popping.

 

You could string line the ceiling (masons line pulled as tight as humanly possible, but kept 1" down or so, so that you can spot any dip in the ceiling.) and see if it's sagging. Since you can recreate the noise by pushing on the ceiling, it's got to be a framing issue... maybe undersized ceiling joists for the span and dead load on them.

 

I was thinking about that possibility. It may be related to the weight of the additional insulation. Also, the popping is coming only from the rooms with the longer joist spans. I was considering crawling up into the attic (when it gets warmer!) and running an vertical stud from the bottom chord up toward the peak in the areas of long spans where there is no wall supporting. I'd just need to venture up there with a number of pre-cut boards, a drill and a box of construction screws. If I did that, would there be any problem just attaching the top of that vertical piece to one side of the peak? Or perhaps stagger which side of the peak I attach to?

 

That seems likely.

Rather than connecting to the ridge (actually to the rafters right next to the ridge), it might be more practical to first install a horizontal collar tie across the rafters, to connect the rafters on each side of your ridge. This forms a smaller, stronger triangle in the upper 1/3 of the roof. Then from the point where the collar tie and the rafter meet, you could then brace your ceiling joists (which you would have raised up to straight with a temporary wall from below). Many small triangles are the strongest shape for building roof trusses, so rather than just bracing vertically, you would create a triangle from the point where your collar tie and rafter meet by running 2 boards diagonally down to 2 places on your ceiling joist. If your framing members are flush with one another. you would make a gusset plate out of plywood, glue and nails/screws to reinforce your joints. You could also use Simpson mending plates or simpson tie plates. You can also nail alongside the joists, but you can figure out which method is best.

How much room to do you have in your attic? (i.e. distance from the ceiling joist to the ridge.)

 

I just google the simpson plates. So just like on pre-fab truss construction. Sounds a little more involved than I thought, but not out of the question for me to crawl up there and do it myself. Thanks for your advice!

 

Right. You would be creating something similar to the common truss or attic truss, pictured in the link below. I'm just assuming you have a central load bearing wall in this ranch? You would want to figure out the best way to brace the ceiling joist at its midspan... wherever that may be.

http://www.srbebuildingsupplies.co.u.../rooftruss.gif

PS, watch out for the blizzard heading your way. Its nasty here today!

 

I am sorry to resurrect an old thread but I am experiencing almost identical issue in my 2 year old home in Chicago. I have annoying popping noise (almost like someone tapping on drywall) when the heater or AC is running (I have 2 stage and worst when the 2nd stage is running). I can make the same noise when I press up on the ceiling.

When I walk on the attic joist over the room, I can hear some creaking which could be causing the noise. I've tried everything including adding more screws throughout the noise area but to no avail. I have 5/8" drywall and they appeared to be screwed but not glued.

Both supply and return vents are in the ceiling where noise is most prevalent and seemed to occur again when the blower is running high. I can also simulate by opening or closing the door in this room.

I am planning to call HVAC to see if they can check things out - too much air pressure? I am attaching picture of the attic above so you can see the rafters and joists.