Inheritance file placement

If I had a Building project...and a Building was made up of ADTs such as Rooms, Hallways, etc. Where would I put these different files? Would I just make a Building project and have all these different files in the same source and header folder? Or do people make new projects for each ADT? And if I had a Bathroom object that was a subclass of Room, do you just place Bathroom files in the same folder as Room files? I know everyone might have their own way of doing it but I figure there must be a general way of handling it when people create large projects. Or could someone refer to a website or anything that could help me out?

A good rule of thumb is to put each class in its own header and source file. All those files that belong to the same project would go in the same folder.

Since all your ADTs are related to Buildings, I think it makes sense to have one Building project and put all the header and source files in the same folder and add all the files to that project. It doesn't sound like your program is big enough for multiple projects or multiple folders yet.