Insulating inside cement blocks

[matouse3]

Ok, so my footing, 3 rows of block, and radiant-ready slab are poured. I am waiting on the contractor to get to throwing the building up, so as I'm walking around my beautiful fresh slab I was thinking about spraying some foam into the open spaces in the cement blocks around the foundation.
Anyone done this? Is it worth while?

Any thoughts are appreciated.

 

[red]

Not sure as to your request. Would be cautious with a expanding capabilities of foam. Have seen foam peanuts and vermiculite use as insulation inside the cores.

 

[matouse3]

I think I found my answer here:

http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11570

Looks like they suggest spray foam in the cores (or vermiculite as you suggested) but it likely doesn't do much for your heat loss as the bulk of loss goes through the solid parts of the block. Foam board against the block is the way to go if possible.