Note: the below image is distorted (curved lines) because of the panoramic picture)
I had old tiles in the remote corner showed in this picture. Those came off the wall taking the drywall with them. As I was trying to put the drywall back I noticed that there was a 1/4" gap between the wall and the drywall at the bottom of the drywall that was still attached to the wall and I realized it will be very difficult to match that exact gap, keep the wall plumb (it was not plumb anyway) and install tiles there.
After a closer look to the wall I realized there was a long and narrow piece of drywall installed horizontally and that was tilted in a strange way so I wanted to check what was there and I removed that and the result is what is in the picture below
The drywall is covering two sections of the same cinder block wall (this is an interior wall in the basement, load bearing, rooms on both side The room I am working in is an old bathroom that went through 2-3 renos over 60Y and each round added more patch work and more corners were cut.
In this case the bottom right section of the wall was completely unfinished so they installed 1/4" plywood strips to bring it to the same level as the left side but that did not work quite well and not sure why they ended up doing wet shimming but on the left side; I suspect that they screwed the right side of the sheet and since the furring strips were not level with the left side that pushed the drywall toward the center of the roomat the left side of the panel when they screwed the right side (it pivoted a little). So what they did to fix that was to add wet mud behind the drywall board on the left side that was 1/4" away of the wall
I am now paying the price and I am trying to fix this bad work. My plan is to bring the furring strips level with the left side (the finished side of the cinder block wall) and then to put the drywall back. They attached the drywall directly to the wall by pre drilling holes and stuffing them with copper wire and then they used drywall screws to attach the drywall. Is there a better way to do this ? Tapcon screws??