How to restore a folder to its original

I got a problem restoring the file permission of the folder of one of the users. Last thing I could remember is that I change the permission of the folder from “full control” to “add & read” using the administrator account. After what I did the usernotice that everytime she open a file from that folder it’s now read only. So I change back the permission from “read & add” to “full control” but still the same problem the files are now read only. When I check the property of the file, it says theowner is Administrator. My problem now is how to restore the folder to its original permission.