Is the height of smallpox from bottom to top or from top to bottom?

From bottom to top. Ceiling. Ceiling from bottom to top. Some top surfaces are uneven. After laying tiles from bottom to top, it has been leveled. The height between the ceiling is generally 10 ~ 20cm, mainly considering:

1. Layout of pipelines and lines.

2, the height of the floor itself, considering the space factor of the room.

3. Installation requirements of integrated appliances for integrated ceilings such as Yuba, ventilator and lighting.