I live in a 1st floor condo and I have decided to add green glue and a layer of 5/8" drywall to 2 shared walls. One of the shared walls is only shared for 2/3 of the way down the wall and then I have a door that goes to the exterior. Obviously I'm only concerned about adding the extra layer on the 2/3 that is shared but I have to carry it all the way down around the door so it is even. If I do that,how is the door caseing going to work beacause I have just increased the thickness of the wall around the door. If I just reattach the caseing to the new layer the caseing will be sitting 5/8" off the jamb and will not look right. Thanks for any info guys.
You'll need to make or get enough 5/8" X 3/4" pine, or whatever your jamb is made of, and put it on the front of the jamb to fur out the jamb to make it even with the wall. Then replace the casing nailing it to the fur strips and back nailing it to the wall. Not a hard thing to do at all.