Insulation Door bottom seals
What gap is needed between door, floor and frame : Insulation Door Bottom Seals
Quote from Article entitled What gap is needed between door, floor and frame:
Thus, in most cases, gaps of interior doors on top and on each side are equal to 3 mm, hinges at the bottom should not be less than 2 cm. If you follow these simple rules initially, in the future you will be able to avoid many of the problems and possible reinstalling of the doors.
The full version of the article can be found here.