Terraria – “Valid housing” – does this work

terraria

OK just before I start, I do know what does and doesn't constitute valid housing in Terraria. I'm also playing v1.2.4.1

What I'd like to know is does the "must have a door" requirement also mean "must be accessible", or can I create a walled-off cube with internal doors to satisfy the housing rules? i.e. are any of the houses A, B, C or D in the following diagram valid?

House illustration

If I can, then I'm going to be making pressure-plate/activator automatic doors that don't get torn down in a blood moon.

Best Answer

Assuming that all of those have walls and a light source, those would count as valid housing. The requirement is that it has a door, not that the door go anywhere. Also notable is that wooden platforms count as doors for the housing rule, so you can actually just have a wooden platform separate the rooms from each other as well.

Here is an example of housing with internal doors:

Valid Housing with Internal Doors

If I can, then I'm going to be making pressure-plate/activator automatic doors that don't get torn down in a blood moon.

This is actually a very common strategy to defend from a blood moon. As noted in the Base Defense Guide on the Wiki:

By using actuators and Grey, Brown, Blue or Lihzahrd pressure plates, you can create a player only door that doesn't even require you to use your mouse. Setup the door as you would an active stone/actuator door and because Grey, Brown, Blue or Lihzahrd pressure plates can only be activated by the player no mobs are able to enter (nor escape).

You can also just place a torch or other item in front of the door so that it can only be opened when you are facing towards the outside. From the wiki:

Another way to prevent enemies breaking down your door is to place a non-solid object, such as a chest, wooden platform or other Furniture item, on the inside of the door. This will prevent enemies from opening it but will require the player to face away from the house to open the door.