Replies

1. 
   Gumshoe | May 03, 2005 01:06am | #1

   No problem I can see. I've done it just so the HO could put up special window shades requiring deeper window insets. In fact, as I recall, the elec. carefully ran all his wiring with a fishing line, patched carefully where he had to open the wall, then had a cow when we stripped the plaster to insulate the wall(HO afterthougtht), and had a triple cow when we framed the new wall inside the old one and asked him to move his boxes out!

2. 
   DanH | May 03, 2005 04:39am | #2

   In colder climates adding from the inside is probably the safest method, from a condensation standpoint. And the easiest way to do it is to fasten up foamboard, then drywall over that, but you can build another studwall and go with fiberglass if you wish. Be sure to seal as well as possible from the inside (plastic sheeting, if fiberglass), to keep the vapor barrier close to the inside surface of the wall.

   Of course, you have to deal with window and door openings, and redo floor coverings, etc in some cases, but you probably were well aware of that already. For windows, if you want to really "do it up right", you can add a second window inside of the first.

1. 
   JohnSprung | May 05, 2005 01:47am | #5

   > For windows, if you want to really "do it up right", you can add a second window inside of the first.

   This is well worth doing.  Heat loss thru windows is usually greater than heat loss thru walls, so this will often do more good for less effort than the wall thickening exercise.

    

   -- J.S.

    

3. 
   Tyr | May 03, 2005 07:54am | #3

   Pretty much the same as finishing a basement for which we usually use 2X3 studs and make sure everything is plumb. In a concrete basement the wall is rarely plumb or smooth. I would go with polyiso insulation boards about 2" thick cut to fit between the studs. You can get at least R25 that way. There is a polyiso board maker here that has factory seconds (visual defects) pretty cheap.

   I think others covered the rest. The new stud wall/s are supported on those 2X10's and not weight bearing right? Warming up to the South of you. And a sawyer makes dimensional lumber out of trees right? Tyr

1. 
   timberframer | May 03, 2005 02:48pm | #4

   yes, the wall will be supported by the joists 2x10 i believe and will not bear any weight other than its own....yes i cut fir and larch timbers and dimensional lumber :)

   Edited 5/3/2005 7:50 am ET by morticemike

4. 
   Mongo | May 05, 2005 02:09am | #6

   I'd do a "sorta-kinda" of what a few guys have already written...

   I wouldn't bother with adding studs. I'd do foamboard. Foil-faced polyiso (R6-7 per inch) would be my first choice. Other RFBI will do as well, but with less R- per inch and without the foil face.

   First find the studs and mark their locations on the walls.  You can pull the electrical boxes forward, or build them out later.

   Then fasten the 4' x 8' sheets of foam board to the wall using just a couple of nails with caps to hold each sheet in pplaxe. My first preference would be foil-faced polyisocyanate. Gap the sheets by 1/4" to 3/8ths inch or so.

   Carry the stud markings to the face of the polyiso.

   Then use canned foam to seal the gaps and foil tape (if you choose) to cover the foamed gaps.

   Then run furring strips horizontally across the polyiso, 16" on center. The strips don't have to break over a stud. Screw through the strip, the foam, and into the studs using the tick marks to find the studs.

   Drywall gets screwed to the furring strips.

   Weak points in the thermal envelope will be the rim joists and the windows.

   Just another option. Not sure if you already have an effective one, but with the tightness of the polyiso, in this case I wouldn't worry about having two vapor barriers.

   Just another idea.