Construction method:
1, determine the highest point of the arch mouth;
2. If the highest point exceeds the top of the existing indoor doorway, the exceeding part will be crushed;
3. After the doorway is smashed, it is necessary to add a lintel to the upper part, and it is recommended to add a steel beam;
4. Then, use light steel keel to make the door opening into an arched hole;
5. Fix the gypsum board on the light keel;
6. Stick an anti-crack bandage at the joint of gypsum board plates for anti-crack treatment;
7. Then scrape gypsum putty on the gypsum board, grind it flat, brush the interface agent, and then paint it.