Supported structures are affected by gravity and can easily be brought down. These will fall into their destruction if tiles or other supporting structures beneath them are gone.
Solid supported structure
These usually take form of a roof or a thin floor. Upon falling, they are harmful to the enemies but not the player. They also knock villagers unconscious.
Non-solid supported structure
Non-solid supported structures usually take a form of pillars and can be walked through. They remove solid tiles (like dirt) above them when destroyed. Non-solid supported structures can hold things such as Falling Hazards when left intact just like their solid counterparts.
There are two types of these:
1. Structures which can be easily destroyed by projectiles passing through them or and by splash damage.
2. Structures which can't be destroyed by attacking them directly but crumble when a solid block underneath it is destroyed.