I have quite a few cracks in my drywall. They run along the drywall seams. They don't seem to affect every drywall seam, just some of them. Some seams that don't have cracks have bubbling of the drywall tape (underneath the paint, etc).

There are cracks in the walls in almost every single room in my house (3-bedroom split level townhouse). The house is 30 years old, so it's not a case of a new house settling. I had a home inspector in and he said the cause was poor mudding initially (when the house was built) combined with a very dry house (Canadian winters..VERY low humidity in the winter). I installed a humidifier into the furnace a few months back, but I still have new cracks forming in the drywall.

Any thoughts what could be causing them?

Or, any idea what the best way is to fix them?

enter image description here

  • Did this begin to happen soon after you bought the house? Can you elaborate on the time span or history? Bubbles under the tape is surely a poor mud job. If the inspector is right I'm not sure you can stop that process by installing a humidifier. If it's cracking it's basically had the moisture sucked out of it and exposing even more surface area to the air. Commented Jan 14, 2015 at 5:14
  • I bought the house this past April (2014). The previous homeowners said that the majority of the cracks had developed within the past year or two (so between 2012-2014). Unfortunately I can't verify how accurate that timeline is, so I have to believe they're being truthful. Since April 2014, there are a few areas/seams that were initially bubbled tape, and have now fully cracked. The new cracks seem to have appeared over the past 2-3 months, so if it really is caused by dry/low-humidity conditions, the timeline would make sense (since it's now mid-winter).
    – shipley
    Commented Jan 14, 2015 at 12:44
  • It seems unusual that these kind of cracks would form in such a short period of time. Check the level of your walls and floors. They should all be pretty level in a newer home. If you are seeing that these areas are out of level, then I would suspect that there is a structural problem. Did the previous homeowners make any renovations? Commented Jan 14, 2015 at 15:11
  • 2
    That size crack looks surprising large to me as well. First guess is structural as Jason says. Second guess is moisture damage.
    – BMitch
    Commented Jan 14, 2015 at 15:20
  • The house itself is 30 years old (built around 1980). The previous homeowners did not do any major renovation - in fact, I think they avoided it. That crack in the photo is one of the bigger cracks, and it's right in the corner. There are also some cracks that are about 1" away from the corners, some vertical above doorways or windows, and 1 that is vertical in the middle of a wall (which is why the inspector thought it was just a drywall tape issue). Worth mentioning: this is a townhouse (I haven't spoken yet with the neighbours to see if they have similar problems)
    – shipley
    Commented Jan 14, 2015 at 15:37

1 Answer 1


It looks to me like the cracks are appearing on the board joins.

Some possible causes there are:

  • Something went wrong with the drywall tape, or there was no tape used at all? You may want to scratch around and try to find some of the tape? I think i can actually see a bubble seam on the wall, indicating that your tape is pushing out. I would say they didn't pre-fill the join seams when applying tape -- basically a poor taping and preparation job.

enter image description here

Other - Less likely Faults:

  • The boards may not be secure enough (ie, enough lateral supports, and my be vibrating too much (wind or knocks)
  • Structural Fault - do they all follow some sort of pattern? the house may be settling and structurally changing
  • Excess Moisture: easy to check (if the area around the crack is damp)
  • This sounds promising - I will check later to see if there is any tape. It doesn't follow any sort of pattern, and it has never felt damp (even through the summer), so it leads me to believe it could just be a terrible tape job. In terms of fixing it, what would you recommend? Tearing out the tape (or sanding down the bubbles) and re-mudding? Or patching with spackle?
    – shipley
    Commented Jan 15, 2015 at 14:34

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