On Nov 16, 5:43 pm, "
wrote:
I am looking to remodel my condo unit, which was originally built as
cheap apartments for factory workers and college students. You can
imagine the shortcuts the builders took... the unit was built in 1970.
Anyway, I am planning on replacing windows, doors, and the HVAC
system. All (or most) of the walls will be completely opened up
anyway, and I may end up rewiring and replumbing, too. (I've got
friends who are licensed in these areas!)
The exterior walls (not the party walls shared with adjoining units)
are usually cold in winter and very warm in summer (upstate NY).
There is insulation, but the unit only has 2x4 walls. I was
wondering... is there a relatively painless way to increase the wall
thickness? Is it worth it? What are the issues with doing this?

Depends on your definition of pain... You would basically be framing
an exact duplicate of the outside wall inside the room. 2x4s are the
smallest pieces of lumber you can get these days relatively straight,
so you'll end up with a 7" thick wall cavity and R25 insulation on the
exterior walls. That's more than the normal 5-1/2" wall cavity with
R19 insulation that's typical in upstate NY. Of course you can rip all
the 2x4s down to 2", but then they'll probably twist and warp, and
you'll have lots of slightly undersize 2x2s to throw away.

If you're going to rewire anyway, it's not so bad. Moving the existing
wiring to the new inner stud wall might be very painful.

For ultimate in noise and insulating properties, leave 1/2" in between
the two stud walls.

All the windows and doors will need special extension jambs for the
extra-thick exterior walls. They'll need to be custom made, most
likely.