hoping someone can help.Our lath and plaster walls have many cracks and some bulges.We need to rewire house and are thinking of taking down the lath.Our concerned is -will we need to reframe in order to insulate and put up drywall?Thanks
Here's one consideration to start with.
In any house old enough to have lath and plaster, you are likely to find multiple generations of "2x4" studs that were used in successive renovations over the decades. Their "4 inch" width can be inconsistent, and possibly not the same as a standard 2x4 you can buy today.
So, any reframing work that you do (adding or removing doors or windows, repairing cracked framing, and so on) needs careful planning by someone familiar with this challenge so that you can ensure that each wall has flush studs. Your carpenter might use some combination of saving and re-using studs from demolition, offsetting studs or customizing 2x4s from 2x6s.
It's not difficult and doesn't add much expense but someone who is only used to new construction will be challenged by it.
Re-frame - not unless you fnd the current framing to be badly damaged behind the plaster & lath.
Shimming or furring to make the wall straight and plumb (if you care about that) - quite likely, but a far cry from reframing.
Depending on your climate you might want to take shimming to a point where it resembles reframing, by putting up a non-bearing wall a few inches inside the old wall (with studs offset from the original studs or stud-equivalents, and at some nice modern spacing like 24" given it's non-bearing) so that you can add far more insulation - but it's still the original frame holding the building up. You lose a few inches of space in the room, and get reduced heating and cooling bills.