What is the ruling on taking an interest-based loan from the bank to build a house, with no intention of repaying the loan and no intention of ever repaying it?

Borrowing with interest (riba) and then refusing to repay it is impermissible. You must repent to Allah with sincere repentance. You are only required to repay the principal amount of the loan, for Allah Almighty says: "But if you repent, you may have your principal – [thus] you do not wrong, nor are you wronged." If repaying the full amount is legally obligatory, then there is no blame upon you, Allah willing, provided your repentance is sincere.