Replies

1. 
   Riversong | Dec 19, 2008 01:20am | #1

   Use a foam-compatible adhesive, and you'll eliminate the thermal bridging through the fasteners.

    

   Riversong HouseWright

   Design *  * Build *  * Renovate *  * Consult
   Solar & Super-Insulated Healthy Homes
1. 
   RhondaRay | Dec 19, 2008 03:22am | #2

   My initial solution but the building inspector wants us to apply a 6 mil vapor barrier between the block wall and the insulation.

1. 
   RobWes | Dec 19, 2008 04:17am | #3

   Then screw it.

2. 
   caseyr | Dec 19, 2008 07:26am | #5

   Most foam is a moisture retarder or even a moisture barrier. I don't understand where an additional vapor barrier would improve things, particularly if you used closed cell foam. You would need to seal everything up, of course. Can't you document that the foam can serve the same function as a vapor barrier?

2. 
   RhondaRay | Dec 19, 2008 04:49pm | #6

   Inspector was convinced that 2" Thermax with vapor barrier would suffice, could you recommend "a foam-compatible adhesive"thanks

1. 
   frammer52 | Dec 19, 2008 05:58pm | #7

   Great stuff foam in a can.  Buy it from HD.

2. 
   Riversong | Dec 20, 2008 12:33am | #8

   Inspector was convinced that 2" Thermax with vapor barrier would suffice, could you recommend "a foam-compatible adhesive"

   Depending on what R-value you're aiming for, 2" XPS (styrofoam) is also a vapor barrier.

   Any construction adhesive would work with foil-faced foam board. I use PL-300 for XPS. I believe Liquid Nails is also foam-compatible. 

   Riversong HouseWright

   Design *  * Build *  * Renovate *  * ConsultSolar & Super-Insulated Healthy Homes

1. 
   Snort | Dec 20, 2008 01:40am | #10

   PL makes a foam board adhesive. Soccer ball sized circles of it seem to have better gription. Sometimes you'll have to rig up deadmen with some weight or force until the glue cures. We do all the seams, too. Not sure where you are, but check to see if you need to leave off a few inches at the top of the foundation for a termite inspection.Hilti makes a gun that shoots fasteners with big plastic washer heads, but it's about $700 new. Now you see this one-eyed midget

   Shouting the word "NOW"

   And you say, "For what reason?"

   And he says, "How?"

   And you say, "What does this mean?"

   And he screams back, "You're a cow

   Give me some milk

   Or else go home"

3. 
   Scott | Dec 20, 2008 01:09am | #9

   >>>could you recommend "a foam-compatible adhesive"PL300Get the big tubes if you're using lots.Scott.

   Edited 12/19/2008 5:09 pm by Scott

2. 
   RedfordHenry | Dec 19, 2008 07:19am | #4

   Ramset makes a 3" nail, but I wouldn't even try doing what you are suggesting.  Besides just blowing through the foam, the flash might even ignite the foam!