Gypsum board ceiling installation corner must be seven-shaped
This is not necessarily, as long as the long-term construction found in such a way, can be formed with the keel joints dislocation, in order to reduce the probability of cracks on the board.
You should say is mineral wool gypsum board bar (specifications 600 × 600 or 600 × 1200), the corner must be used piece "L" type, or take the sub-bone and edge aluminum. Norms also have this requirement.
