The position of the header and back jambs are very important.
How to install a 9 by 7 garage door.
Make sure that the size of the opening matches the size of the door.
If your opening differs from this you may have to order a specialty door.
Measure the various areas where the door will be installed.
A standard double garage door is 7 ft.
A door of 9 x 7 2743 x 2134 mm needs an opening of 9 2 743 mm wide by 7 2 134 mm high.
High by 8 or 9 ft.
High by 16 ft.
The header must be flush on the same plane with back jambs.
Standard single doors are 7 ft.
Because the doors are so large few home centers and only some garage door stores keep many doors in stock so expect to order one instead of buying it off the shelf.