I live in a large house shared with several roommates. We each have our own lease with the landlord. The landlord has been letting himself into the house frequently with no explanation. I was under the impression this was illegal, but am not sure considering the landlord only enters common areas such as hallways and the kitchen (though these are still within the confines of the house).

I found the information here saying

A landlord may enter:

• Any common areas that are shared with others like hallways, courtyards and laundry facilities – no notice is required

This seems to be talking more about apartment buildings with hallways anyone can walk through.

Without warning or reason, can the landlord knock on the door and be allowed in if whoever answers says it's okay?