Cause for cracks around window on only inside?

[psychedomination]

I did an inspection of a house a few days ago, where the owner wanted to check some cracks around their window amongst other things.

I am a bit stumped one this, as there are distinct cracks around the window on the inside (yellow walls) but there aren't signs of stress cracks on the wall when looking from the outside (white walls).

I am trying to brainstorm some potential reasons for the cracking to determine whether it is a cause for concern or not.

1. First thought is that the window width itself is larger than the window clear opening. The contractor may have cut a cavity into the wall for the window to extend into and not sealed it. Lateral loads from normal operation and wind could have caused the wall to crack.

2. I'm not sure if this interior portion is just plaster? But same as above, lateral forces could have caused it to crack.

3. The lintel above the door may be inadequate or not exist causing the window frame to bow out and crack the wall.

I'm not sure if anyone has come across this but any help would be appreciated on a cause and fix.

 

[dhengr]

Psychedomination:
That 135° corner is not framed correctly. The exterior stucco is just a little stiffer and more resilient than the interior finish, so the exterior isn’t showing cracks yet. There has also probably been a little water intrusion around the windows and into the framing, see the paint chipping and flaking. Each of the window framing planes is acting as its own very flexible diaphragm, and deflecting/parallelogram w.r.t. the adjacent framing planes, and they are not properly tied together at those corners, over their height, so there is vert. and lateral movement btwn. the two planes at each corner.

Maybe they should paint the int. walls white and the problem will go away. Or you could investigate further and at least know what the makeup of the various parts is, and how they are actually put together. It will take some destructive inspection to open up a few of those corners up to see what’s actually there and how it is framed, before you can determine a fix.

 

[psychedomination]

Thanks for the comments so far dhengr.

I really appreciate your guidance.

The house is made of hollow CMU block. I note your point about the incorrect corner construction. I’m looking for some examples of a suitable CMU wall 135 degree corner detail that has a running bond arrangement for shear transfer but I am struggling to find much information on this detail for a standard CMU block (not bespoke).

It appears as though the existing 135 degree corner may need to be replaced with a 135 degree reinforced concrete wall (unless there are potentially cheaper alternatives to tie the existing?). I should note though that there is a tie beam/bond beam at the ceiling level, going around all the exterior walls (although you are correct that at the window level the corners don’t appear to be connected).

That is a good point about the water intrusion, which has also perhaps assisted with the facilitation of crack propagation.

I guess if they really didn’t want to pay any money on further destructive investigations, the owners could just replaster (seeing as it appears to be a finishing issue rather than a structural failure) the wall and repaint but the issue will most likely come back in the future.

Or even easier like you said, just paint it white and problem solved (right? )