The head casing should cover the gap created up top although you might have to touch up the paint on the gyprock.
Large gap between door and floor.
This is a simple solution to your problem.
When we remodel manufactured home we almost always replace the interior doors with new and better ones.
Foam backer rod is a flexible rope that compresses to fill.
Because smaller gaps will transfer the air as efficiently as larger gaps there is no real reason the gaps need to be 3 inches.
Pop the door and frame cut the jambs down by a half inch and re install with the jambs hard down.
First of all you have to decide on the size of the garage door bottom seal you require.
This is what i particularly suggest for the front door to keep our.
My contractor just hung our fancy dancy un painted solid wood door slabs in my 100 year old house with solid hardwood floors throughout.
If you have a large gap beneath the door use a wrap around door sweep.
This number is regardless of flooring.
It is about a little less than a 1 4 of an inch.
If you have a large gap at the bottom of your door that may be helping the door to stay plumb.
As we are focusing on uneven floors mostly you need to measure the size of multiple gaps your garage door has from the floor.
There is an approximately 1 5 gap at the bottom of the doors.
The foam should be the same diameter as the width of the gap.
If each room has individual air returns the numbers can be smaller for personal taste.
Press a closed cell foam backer rod into the gap starting at the corner.
Reset the door so that it is level and plumb.
This is the alternative to using a door sweep.
Under all the door casings there is a gap between the casing and the hardwood floor.
Here the gap is the distance between the floor and the bottom of the door.
Check that the stud walls on either side are plumb before you get into bigger issues.
This allows for proper air exchange between rooms.
The larger the gap the more sound that seems to transfer between rooms.
The contractors tried to seal it using caulk but it doesn t look so great in my opinion.
They have long adjustable sides that can be moved.
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.
Shim it and nail it and hang the trim.
It should be measured from the floor surface to the bottom of the door.