How do you introduce clean air into the house?
Nice thread on insulation types and issues. But once the house is air tight how do you get good clean air inside? I admit to being nervous about foam; if something really negative is found, removing the stuff might cost half the value of the house. All these materials are deemed to be “mold resistant” but what we do in our house creates water vapor and if not allowed to escape would provide the support for mold.
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You need a mechanical ventilation system. Our code requires one.
You raise at least two issues: one concerns ventilation, and the other concerns mold prevention.
For more on ventilation, you should read the article that Malcolm suggested, in addition to this one: Revisiting Ventilation.
When it comes to mold prevention, the trick is to make sure that the relative humidity (RH) of your interior air stays low enough to prevent mold growth. For more on that issue, see this article: Preventing Water Entry Into a Home.