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rob0781 04-18-2010 05:53 PM

basement insulation
When insulating a basement with styrofoam insulation should a plastic vapor barrier still be used between the styrofoam and drywall?

Cork-Guy 04-19-2010 10:32 AM

I would check with local building codes to get an accurate answer to this question.

rob0781 04-19-2010 07:17 PM

well is vapour barrier normally just used because its code? i was thinking it would keep any moisture from ruining my drywall, but if its not needed i wont bother wasting the money.

Cork-Guy 04-19-2010 09:56 PM

Well, it's not "just" used because of code, it does prevent moisture from ruining your drywall. However, you might "not" need it, but still might be required by building code in your county\city. That's why I said check your local building codes first, if it's required per code than it doesn't matter if you do or don't need it; you have to do it!

Now, don't think if I don't do it they'll never know! If something due to not having a vapor barrier occurs and you need to use your homeowners insurance and an inspector finds out you didn't follow code your policy WON'T cover it. Worst case scenario, but it's better to be safe rather than sorry.

Perry525 04-20-2010 11:47 AM

It is a matter of fact that water vapour always makes for a cold surface to condense.
The concrete in your cellar is always cold. If you are going to add insulation then the concrete will loose the benefit of the warmth it gets from the air at present and will become even colder.

If you are going to live in your cellar you will no doubt try to keep it warm.

And warm air holds a lot of water vapour from your breathing and sweating.

Therefore, you must have an almost water vapour plastic barrier between your warm air and the concrete.

It should be fitted underneath the drywall and you must take great care to ensure there are no holes, holes equal access for water vapour and in time mould and wood rot.

nealtw 12-14-2010 10:53 PM

The foam is a good barrier just tape the joints with tuck tape tuck tape is red.

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