"This is not valid housing" appearing but the housing in question looks completely valid

[Jelenir]

Both of the houses have a chair, a table, a background wall, a light source, and are large enough, but the message "This is not valid housing" still shows up. What's going on?

 

[Green_Metaknight]

It needs to have blocks in the floor. If the entire floor is platforms, it won't work.

 

[Kitnight]

It needs to have blocks in the floor. If the entire floor is platforms, it won't work.

Yep, there needs to be at least 3 solid blocks to count.

 

[Jet-Powered Rope God🌳]

Yep, there needs to be at least 3 solid blocks to count.

Im pretty sure it's only 2.

 

[Kitnight]

Im pretty sure it's only 2.

Very well could be, I was only going off of memory, and my memory isn't the greatest.

 

[Dapling]

Im pretty sure it's only 2.

It’s 1, but the block can’t be up against a vertical wall