Why is my terraria house on PS3 invalid?

Answer 1

Your house must be:

A size of 60 tiles in total at least (but no more than 750), so you could have it 6 tiles by 10, for example,

It must be fully enclosed, by blocks, platforms or doors, including at least one solid block on the floor,

It must also contain at least one light source, one 'flat surface' item such as a table or dresser, and one 'comfort' item such as a chair or bed.

Lastly it must also have a player-placed back wall. Naturally occuring dirt walls do not count, but player-placed ones do. Some other natural walls will count, such as Planked Walls or Boreal Wood Walls, which you sometimes see in underground houses.