Building Valid Houses

An NPC house needs walls, a light source, a flat surface (table) and a comfort item (chair), plus a door and enclosing background walls.

1. 1Lay a solid floor and build walls at least 6 wide × 4 tall.
2. 2Fill the inside with background walls (not platforms) using Wood Walls.
3. 3Place a table, a chair and a Torch.
4. 4Add a door so the NPC can enter.
5. 5Check the house with the ? housing menu — it must say 'This housing is valid'.