So, today the Demolitionist appeared, and night has now fallen, but instead of going to the cosy NPC friendly house I had ready for him, he seems to constantly wander between my house and the guide's house (which actually has an empty floor that he could move into anyways).
See this picture for detail:
As you can see, the demolitionist seems torn between my humble abode (circled in red), and the house of the guide, who has a free floor anyway (circled in blue). He won't settle anywhere, not in the empty floor in the guides house, or the lovely house I had build in anticipation of his arrival thats off screen to the right.
The noise of him constantly shutting and opening the doors is driving me insane, and the dark thoughts of going on a quest to find lava and commit demolistionisticide are growing even stronger with every second.
Best Answer
If your demolitionist has claimed a room offscreen, you may need to go far enough away that he teleports 'home'. He's not going anywhere because he can't reach his house in the first place.