You have addressed series of questions regarding the use of expanding foam insulation in houses. My interest is particularly attic space. The advice given cited two particularly alarming incidents you had become aware of: moisture buildup causing roof decking to rot and mold growth having to be remediated. Correcting either of those would involve greater cost than that of the foam insulation itself, not to mention the health issues. Can you tell me whether the type foam referenced was “open cell” or “closed cell” and approximately how old the installation was at the time the problems were discovered?
David
Tom: Well, let’s straighten this question out first because it’s down the wrong road. Let’s go back to the intersection.
We’re in an attic. Foam can be used on concrete blocks for walls and stuff. I mean, it has places for it to be used. Everything does, but now we’re talking about an attic that needs to breathe, so an attic has to have ventilation to remove the water vapor that builds up in an attic, and that’s why we use ridge vents, and soffit vents.
Now, you take the foam system, and whether it’s open or closed, I really don’t give two poots. The bottom line is, is you’re closing that attic up tight so there’s nowhere for the water vapor to go.
So, you either have to use a dehumidifier in the attic, which a lot of people do, but that costs money to run and more equipment to buy, and not always that reliable and can cause a big problem, and so people don’t do that, and so you have a closed attic that is going to get very wet in there, and because of the foam and the way it’s not vented, and so that’s the problem.
You’ve got to vent your attic, and if you vent your attic, why have the foam? It doesn’t make any sense.
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