Answer:
Maison is House ( note similarity to Mansion) I think the usage is about the same. Certain words in English have house in them but are more accurately Rooms - the Wheelhouse of a ship, for example. Sometimes House applies to an institution ( Nut House) which of necessity has more than one building or buildings but is still singular- then the usage of Royal Houses- like Windsor. also in french we have batiment ( building, which is generic).