Replies

1. 
   BobKovacs | Oct 28, 2004 11:46pm | #1

   I'd be more concerned about how you're going to avoid destroying the wall when you spray the foam in.  As I'm sure you know, the foam expands rapidly to many times it's original volume, and if it's got nowhere to go, it'll rip the wall right apart. 

   Bob

1. 
   leftisright | Oct 29, 2004 12:26am | #2

   and how is the wall going to drain?

1. 
   BobKovacs | Oct 29, 2004 01:51am | #3

   An excellent question- kinda eliminates the "cavity" in "cavity wall system", huh?

2. 
   Bryant | Oct 29, 2004 05:30am | #5

   These walls do not normally have free water in this air space but does it change things a little more subtly around the breathing and humidity of the house for instance? 

2. 
   Bryant | Oct 29, 2004 05:27am | #4

   I have seen it done.  It has a different formula that allows it to run and then expand slowly without blowing out the walls.  But what about my original question?

2. 
   nikkiwood | Oct 29, 2004 07:50am | #6

   That's the kind of construction used in my house, except that I have 3 courses of brick.

   I consulted with a number of experts, and was advised that the gain (of insulating ) would be marginal at best.

   However, whenever I demoed a room, I did install sheets of styrofoam between the furring strips (that held the lath), and then reapplied strips of lath to the furring strips, with 1/2" sheetrock replacing the plaster.

   I always used a vapor barrier paint as a primer (on the exterior wall). some of these walls have been in place now for 20 years, and there haven't been any problems.

   I did stud wall/insulate the basement walls, and went all the way to R 70 in the attic. These measures made a huge difference in the heating bills (along with installing a high efficiency boiler).