If the property is partially damaged, you should get a rent reduction for the parts of the property that you can’t use. This isn’t automatic though – you shouldn’t stop paying before you and your landlord agree.
If whole rooms aren’t usable, you should get a rent reduction for those rooms. For example, if half of the house is unusable, your rent should be reduced by half.
If some facilities aren’t usable, you should get a rent reduction for the cost of the inconvenience caused. For example, if your shower isn’t working, your rent should be reduced to reflect the cost of showering somewhere else.
If you don’t want to stay in the property while it is being fixed, you and should try to come to an agreement with the landlord about staying elsewhere (and not paying rent) while the repairs are done, or ending the tenancy. If you can’t agree, you or your landlord can apply to the Tenancy Tribunal to help make and order a decision.