The outstanding loan does not affect the ownership of the house, so the house sales contract is legal and valid. Contract Law: Article 8 A legally established contract is legally binding on the parties. The parties shall perform their obligations as agreed, and shall not alter or terminate the contract without authorization. Contracts established according to law are protected by law. Article 52 A contract is null and void under any of the following circumstances: (1) One party concludes a contract by fraud or coercion, which harms the interests of the state; (2) Malicious collusion that harms the interests of the state, the collective or a third party; (3) Covering up illegal purposes in a legal form; (4) damaging the public interest; (5) Violating the mandatory provisions of laws and administrative regulations.