Jomama-- that's an embarrassingly good point. When I first read this, I envisioned the rock walls, and the extent of the renovations, and I guess I assumed it was a below-grade structure that was being upgraded, where rock walls are more common. That's definitely not necessarily true. It might be because I was just coming out of a forum question where I was talking about wet basements-- maybe it was on my mind? My bad. :-/
Jlk -- That may be true, and it may even be true more often than not, but it's not something I would bet my reputation on. At the very least, I would install a plastic vapor barrier on the walls beforehand, even if
it was my house. But hey, if it works? :-)
It's hard to say " Do it this way" without knowing details like what your location is? Is it a higher humidity environment inside or out? How much money do you want to throw at this? As they say the devil is in the details.
So here's something that will work in most installations.
Try 1" of Polyisocyanurate hard insulation board directly against the concrete walls, covering the entire wall. You can use construction adhesive to hold the insulation board up. Just don't go crazy with the adhesive. Make sure it's the grooved type insulated board and use PL adhesive in the grooves to joint all the board together. That should give you a R-7 surface that is considered an excellent vapor retarder and close to what is often misnamed a vapor barrier. Then frame the hard insulation in with 2x2s or 2x4s, filling the space in between with either R11 - R19 insulation (non-kraft backed). Finally put up your drywall or sheet rock. Your final overall R value should be somewhere between 19-28. Make sure you gasket your electrical outlets.
BTW the 1" Polyisocyanurate at home depot and lowes are aluminum faced to you are also adding a radiant barrier to your walls which should also help if any of your walls are facing the southern-western sky.
Last edited by mackintire; 12-09-2010 at 12:09 PM.