1. The rental contract was not signed by the owner. If the child is approved by the owner or entrusted in writing, it is valid to sign the contract on his behalf;

2. If the child does not have the consent of the owner of the house, the privately signed contract is invalid.

Whether the non-signed house purchase contract is valid or not depends on the situation, as follows:

1. If an agent signs a contract without the authorization of the parties, it is an unauthorized agent and the contract signed by the agent is invalid. No matter what happens, the agent will be responsible for the signed contract. However, if the other party has reason to believe that the person signing the contract has a power of attorney and signs the contract with him, the legal consequences of his behavior shall be borne by the principal.

2. A signature is valid if it is legally authorized or ratified afterwards.

Whether the contract signed by the intermediary is valid is as follows:

1. An intermediary company can sign a lease contract with the landlord if it has a lease power of attorney from the landlord. This form is actually that the intermediary first signs a lease agreement with the landlord, and then the intermediary sublets the house. The intermediary company is equivalent to the second landlord. If the intermediary company does not obtain the permission of the landlord, then the contract signed is invalid;

2. In addition, as long as both parties have corresponding capacity for civil conduct, the signed contract is valid on a voluntary basis without violating legal or social interests.

Whether the sales contract signed by the owner himself is valid is as follows:

1. The owner's signature is not required. If the person signing on behalf of the owner is entrusted by the owner or the performance of the person signing on behalf of the owner makes the other party have sufficient reason to believe that the client is authorized by the owner and has legal effect.

2. Before the owner knew that someone had signed the contract on behalf of the owner, he may not have indicated it, but in the other party's view, the owner knew that although he did not issue a power of attorney, he acquiesced in the legality of the act, and such a contract was legally binding.

To sum up, the rental contract was not signed by the owner. If the children are approved by the owner or entrusted in writing, the signing contract is valid.

Legal basis:

Article 153 of the Civil Code of People's Republic of China (PRC)

A civil juristic act that violates the mandatory provisions of laws and administrative regulations is invalid. However, unless mandatory provisions do not invalidate civil legal acts. A civil legal act that violates public order and good customs is invalid.

Article 154

A civil legal act in which the actor and the counterpart collude maliciously and harm the legitimate rights and interests of others is invalid.