In every tenancy contract there is an obligation by the landlord to repair and keep in repair the structure and exterior of the home and the installations for the provision of water, drainage and power. There is also an obligation by the landlord to keep in repair the sanitary installations in the bathroom, ie: the bath/shower, the lavatory and the bathroom sink.
These terms are automatically implied into most tenancy contracts/letting agreements by the law. There may also be other terms in your tenancy agreement which may mean the landlord has to do more even than what the law implies into the tenancy agreement.
In addition, even if not caused by disrepair, it might be possible to get your landlord to deal with condensation related damp and mould.