Do I need a vapor barrier in my basement?
I’ve been looking in varios places trying to figure out if I need a vapor barrier in my basement if I use ridgid foam panels.
My plan is to glue foam panels to the (poured) foundation, frame the walls with 2×4, insluate with fibreglass and close it all up with drywall.
Now, some posts say that I don’t need a vapor barrier between the 2×4+fibregalss and dryawall to avoid a double vapor barrier situation that will trap moisture and I agree with that but I want to check with you to make sure I’m not making a mistake. So do I need one or not?
Also, some posts say that fibreglass insualtion should not be used in a basemet, is that true? Currently I have the pink insulation with poly going down the wall about half way (that’s how the builder left the basement).
If I can’t use fibreglass insulation then what else can I use that is not going to cost me an arm and a leg?
If I don’t use the foam panels then is this correct: tar paper, 2×4, poly and drywall?
Thanks
D.
Replies
This might be a product for you to look at:
got to
http://www.warehousebay.com/
and look up "InSoFast Insulated Self-Framing Panels"
This site used to have a bunch of useful info, but it looks different than the last time I was there:
http://www.buildingscience.com/resources/vapor_barrier_code_changes
This site used to have a bunch of useful info, but it looks different than the last time I was there:
http://www.buildingscience.com/resources/vapor_barrier_code_changes
It won't hurt to install a vapor barrier against the concrete. Won't necessarily help, isn't necessarily needed. But (assuming this isn't the dry desert) you want to avoid any sort of vapor barrier on the room side of the wall.
You should have something -- at least tar paper, preferably rubber membrane, plastic spacers, foam sill seal, etc -- between the concrete and any wood. And of course at least the bottom plates should be treated.
Nothing wrong with using FG insulation (though foam is better in many ways), but if the FG has a kraft face you should slash that.