You will have three gaps plus a door jamb.
How to build a french door jamb.
Make sure it s tight and opening in the right direction.
Trace around the hinge and.
Remove the door from the jamb.
Add those measurements to the size of both doors and add an additional 1 1 4 inch to obtain the final dimensions.
Jamb material typically is 3 4 to 1 1 4 inches thick.
Using the marks on the jamb position the hinge on the jamb as if it were already installed.
The door jamb is the vertical portion of the frame that runs along the sides of the door.
Framing for a french door is similar to framing for a single door except there are two doors and each door will be hung one on each side of the opening.
Make certain to weather proof the frame itself and the area surrounding it.
Installing a new door frame is not a difficult task and can be learned by understanding the simple steps involved.
Unless you are installing a prehung door you ll need to trace the outline of the hinges on the jamb and cut an indentation using a router or utility knife.
If you re not using premade jamb material or if your walls are a nonstandard thickness you can buy 5 or 6 inch wide lumber and rip cut it to the width of the wall using a table saw.
However french doors are usually worth the extra effort for once they are up and everything is in order they make a handsome addition to your living space whether they are interior or exterior.
With exterior french doors sealing and weather proofing the door frame to include the door jambs is a much bigger concern.
On exterior french doors the top portion of the frame between the two door jambs will often be larger and heavier than on interior french doors.
You need to allow room to place a vertical side plate and you need a 1 4 inch gap between both the doors and the jamb on each side.
When building a door jamb to fit a standard wall with a two by four frame and 1 2 inch drywall on each side the width of the jamb board typically is 4 9 16 inches.
The door jamb framing.
Place the door in the jamb and fasten it to the hinges.
The jamb frame surrounding the doors themselves consist of side jambs and a top or head jamb across the top.
If you have to replace or repair a door jamb it s most advisable to build an entire new door frame.
Remove one of the hinges from the door.