-
I didn't mean to suggest you needed fire doors, just that they are available as blanks of a thickness more normal for internal doors.
24mm is only 6mm thicker than a lot of kitchen cupboard doors, when you try to use it as a door it can be prone to warping. Especially if you have differences in heat and humidity on either side.
My gran always had heavy curtains behind the doors which came down in the summer. Maybe we'll see a return to that this year, might consider it myself.
Sorry, should have said, don’t really need to be fire doors, they are more just to keep heat in one half of the two rooms.