I'm posting here because you may be experiencing this and can help me. In our home we have found many of the interior joints of drywall where the angle is greater than 90 degrees (in other words a wide angle found in many of our octagonal or similarly shaped rooms)the drywall corner joints are cracking. Whatever they placed in the corners of these joints is separating and cracking into hairline cracks. Obviously something is not right, and our painter mentioned the builder must have used cheap, or plastic, corner joints instead of metal. I can tap on them and determined they are plastic. Someone tried to plaster over the cracking but it continued on. These are hairline cracks, not major structural defects, but they are unsightly. We'd like to fix this the *right* way but haven't figured out if we should screw the plastic into the wall more securely, or rip these out and replace them. There are many of them, so the thought of replacing is daunting. We don't want to do this more than once. My interior paiting is on hold until this issue is resolved. Help!