A 10mm gap under the bathroom door is very usefull it allows the fan to work easier as it can draw in air and because its from within the house it stops the bathroom.
Gap under bathroom door for ventilation.
This is less than desirable in bathrooms and bedrooms.
Using the link you have provided it has a picture of a french full lite door with a vent that has removed a significant part of the door s base.
There is an approximately 1 5 gap at the bottom of the doors.
The flow dropped from an unrestricted 150 160 cfm down to under 100 cfm in each room.
I think it is too big and think a 1 4 1 2 gap would accommodate any unevenness in our floors and allow us to use area rugs.
If more gap is required it is easier to trim a door than to lengthen it.
Client always resist 1 gap over the floor covering.
7 mistakes not to make in your bathroom remodel do let your.
There should be plenty of room under the bottom of the bathroom door to allow air to get into the room so the fan has a source from which to pull the air it needs.
The jumper makes sense in some cases.
My contractor just hung our fancy dancy un painted solid wood door slabs in my 100 year old house with solid hardwood floors throughout.
And for proper bathroom ventilation your exhaust fan needs to vent outside not into the attic or another area of the house.
My mom has a house with a central return and as you suggest her doors have about a 1 5 gap underneath to allow air to flow.
I have a problem with the door vents you are passively promoting.
Check your bathroom door.
However the size of that gap is very unlikely to be greater than 1 2 for any door.
I like the suggestions for wall ceiling jump ducts etc.