As a vapor barrier - no
If the Closed Cell Foam is applied properly though you should have no issues with a moisture sandwich
I have always wondered, if one is dependingI am NOT an expert on this so that's why I ask the manufacturers. This is a reply I got from one of the closed cell foam manufacturers:
"Closed Cell foam is a Code Approved Vapour Barrier with a permeability rating of under 45 ng, as well as a Code Approved Air Barrier and Thermal Insulation. Closed Cell foam is spray applied as a liquid to create an air-tight seal as it expands as a foam to stop air leakage. But unlike Open Cell foam, Closed Cell foam stops both convection through and within the wall cavity"
From the materials/replies I received, it was my opinion that I'd rather not play with closed cell foam insulation because even if it is not a 100% vapor barrier, it would still retard the dehumidification process enough for me to not use it.
Mind you, I'm talking about an exterior wall to shower enclosure in my climate. For me, the Kerdi is enough to keep moisture in the shower and the cellulose is enough insulation to keep the cold out, yet still breath.
I'm all ears if you have some different info!
Got it now. I've had one helluva day..........:sad:Angus I am a little confused on your comments, or maybe I just didn't state mine fully
CC Foam can be used as a vapor barrier - but everything would have to be covered including the studs to make it a true barrier required for use in a CT shower
Why do you need the wall to breathe while using Kerdi? The vapor can't get past it, & you do not have the thermal transfer that creates the condensation issues
Is that clearer or did I just make it worse?