Doorjambs are designed to fit standard width walls made out of 2 by 4 or 2 by 6 lumber plus a layer of 1 2 inch drywall on each side of the wall.
Drywall extends past door jamb.
A buddy of mine does trim work for a living.
It s important to know what to do in less than ideal situations.
Window jambs extend beyond drywall.
The ripped out the plaster and put in drywall and now all of the jambs protrude past the drywall.
The door casing is nailed to the jamb and to the wall and covers the space between the doorjamb and the wall.
As an amazon associate i make.
The first thing you need to do is to determine how long the door jamb extension needs to be.
In the place we re modeled he did much of our trim work and like the op we had many jams that were not parallel nor flush with the walls.
These jambs span from one side of the wall to the other.
Step 2 create the extended door jamb.
Use a measuring tape to record the distance from the drywall to the door edge to determine the length.
Not everything is perfect.
It is an old house 1920 s 2 story that had 2 layers of lathe and plaster on it.
Determine the length of the side jambs and the horizontal jambs.
Mark the outline of the door jamb using a pencil.
Watch a simple way to build and install your own wood trim that also solves a common problem with drywall that extends too far past door and window jambs.