# Sealing joints in XPS foam board



## Tom M (Jan 3, 2007)

So no baffles above the R19? Edge vent is a great product to bring intake in where there is none.


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## dielectricunion (Feb 27, 2013)

I'm going to test this with whatever further detailing I can do before finished surfaces, drywall etc., expecting to, down the line, tear off the roof and either do a hot roof invented, or vented from above.

Then I can document the damages. Is there any probe type hygrometer or humidistat that would work to kind of check up on the state of things from time to time?


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## dielectricunion (Feb 27, 2013)

Tom M said:


> So no baffles above the R19? Edge vent is a great product to bring intake in where there is none.



Checked out the site for this briefly. I assume I'd need to provide baffles or a channel for air under sheathing?

Looks like a good product. I'd like to use it when I'm not totally half asing things. I'm in a bit of an act now pay later to avoid another freezing cold winter with $300+ heating bills to keep thermostat on 52!


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## Morning Wood (Jan 12, 2008)

It would be neat to stick a thermometer and humidistat in the roof in certain areas. Batteries would never last and doing it with wires would be a hassle.


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## dielectricunion (Feb 27, 2013)

One or 3 of those digital weather vanes would be a good idea. The tiny wires from a transformer wouldn't be too bad


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## ScipioAfricanus (Sep 13, 2008)

The IRC allows for non vented attic assemblies but the foam should be tight to the underside of the roof deck.
Then the fiberglass under that and a thermal barrier (drywall) on the underside of the roof rafters.

Andy.


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## ScipioAfricanus (Sep 13, 2008)

I would think that the 6" of foam would be closer to R-30.

Andy.


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## dielectricunion (Feb 27, 2013)

ScipioAfricanus said:


> The IRC allows for non vented attic assemblies but the foam should be tight to the underside of the roof deck.
> Then the fiberglass under that and a thermal barrier (drywall) on the underside of the roof rafters.
> 
> Andy.



So essentially, I got it backwards. Haha. Oops


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