# Insulation



## DangerMouse (Jul 17, 2008)

If you mean soffit vents, you do not seal those with foam or cellulose. They should have baffles to allow air flow through the attic, but not down below to the home.

DM


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## Michael7777 (Jan 2, 2012)

I was told that they seal everything in the attic to not allow humidity to come in . It's acts as a cooler in the attic. He said if you allow the moisture to get in that it makes everything worse


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## DangerMouse (Jul 17, 2008)

More information needed. 

DM


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## Michael7777 (Jan 2, 2012)

I live in Florida .


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## DangerMouse (Jul 17, 2008)

Perhaps we should start with "who told you this?" And maybe roof type/pitch?
Photos are always worth a thousand words here. 

DM


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## Michael7777 (Jan 2, 2012)

Both insulation companies who came out to give me an estimate.


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## Michael7777 (Jan 2, 2012)

I have a tile roof.


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## DangerMouse (Jul 17, 2008)

I can move this to roofing if you wish, the guys there can help you better than I can with this.

DM


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## Gary in WA (Mar 11, 2009)

1. So you must have your HVAC in the attic, with all the ducting, is that correct?

2. How thick a layer are we talking about?

3. Will they add fibrous insulation after that?

4. Where will they be spraying? Joists, rafters, ?

Gary


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## Michael7777 (Jan 2, 2012)

Ok. Thank you


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## Michael7777 (Jan 2, 2012)

The house is CBS construction. I live in Florida. They are apparently going to spray the tie beams above the ceiling and the roof. The spray foam will be about 5 inches thick which will be a little bit higher than what the 2 by 4 is


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## Michael7777 (Jan 2, 2012)

No fibrous material after


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## Michael7777 (Jan 2, 2012)

Hvac?? There are ducts in the attic . It's a one story home


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## Gary in WA (Mar 11, 2009)

Good to go: http://www.joelstiburek.com/topten/south.htm

http://www.buildingscience.com/documents/reports/rr-1001-moisture-safe-unvented-wood-roof-systems


http://best2.thebestconference.org/pdfs/040_EE11-3.pdf

They all say the same thing, just a different slant. The last one is the paper the second one is from. 

And the IRC: "The IRC also *prohibits a vapor retarder on the attic floor* of conditioned attics so that any moisture that may build up in the attic can dissipate into the house. If wood shingles or shakes are used, a ¼-inch air gap must be left above the roof sheathing, but below the shingles or shakes and roofing felt" Read the whole article: http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/article/1520

Gary


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## Gary in WA (Mar 11, 2009)

You still need to meet your R-30 requirements per Code: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec001_par001.htm

http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec002.htm

If an older house, adding the new SPF insulation might meet code or add some cheaper stuff...

Gary


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