Normally the landlord is responsible for keeping the building he is renting in good repair. However the answer to your question depends on what is in the lease agreement. If a fire damaged your possessions inside your house, that is your responsibility. You can obtain renters insurance to protect you from destruction of your personal property inside the house you are renting.
Every situation is different and you should consult your own attorney to go over all the particular facts in your case. The answer given is only intended to provide general guidance regarding rights and responsibilities.