You can deal with door jambs by trimming the molding that conceals the.
Laminate under door trim.
Using a framing square measure the depth of your door jamb by sliding the square under the newly cut gap until the tool hits the door frame or stud.
The 1 2 inch gap is for the doorway only.
If there s a gap under your door casing and also a gap between two rooms under a door where two different installations of laminate flooring join you can install t molding to hide both gaps.
Measure on the inner jamb as well as both sides of the door where the trim is located.
Note that you will leave the standard 1 4 inch expansion gap on either side of the doors.
Install the last row of laminate flooring stopping 1 2 inch from the bottom edge of the patio doors.