# batt insulation and blown in



## Gary in WA (Mar 11, 2009)

Heavy cellulose insulation will compress the lighter f.g. batts, expect some loss of R-value; http://www.greenbuildingadvisor.com/sites/default/files/Compressing fiberglass.JPG

Gary


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## Windows on Wash (Aug 30, 2011)

You will get some compression but you gotta cover those rafters and the cellulose is better are resisting convection.

Make sure the cans are sealed up tight and not just IC rated.


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## langless28 (Nov 20, 2011)

Thanks for the responses. I actually read some older posts stating the weight differences. 

Do they make r30 faced rolls of insulation? I was looking at the two big box stores and it seems that faced r30 is only sold in the precut (more expensive) variety.


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## Fix'n it (Mar 12, 2012)

why are you using batts ? and not just blowing more cellulose ?


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## langless28 (Nov 20, 2011)

Well to be honesty don't know much about insulation. Trying to do my best with research. Is blown in far superior? What would be the vb? Plastic sheet under joists?


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## Fix'n it (Mar 12, 2012)

langless28 said:


> Is blown in far superior?
> 
> What would be the vb? Plastic sheet under joists?


i was told it was.

i was told it isn't needed. and that the paint is all that is needed. 

but, i am sure there is more to it than that. so wait for the pros to chime in.


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## Gary in WA (Mar 11, 2009)

You pretty much covered it! To back-up the claims; http://michaelbluejay.com/electricity/insulation.html

http://www.cellulose.org/HomeOwners/AirVaporBarriers.php

Cellulose ceiling sag; http://www.energyguide.com/library/EnergyLibraryTopic.asp?bid=austin&prd=10&TID=17324&SubjectID=8375

Check with local AHJ for required poly with your State Energy Code; http://www.ecohomemagazine.com/ener...ommon-energy-claims.aspx?printerfriendly=true

Gary


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## Fix'n it (Mar 12, 2012)

1 thing i noticed with the blown cellulose = it gets in the nooks and crannies. i mean, it REALLY gets in there ! and the pro's here feel this to be a very good thing.


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## langless28 (Nov 20, 2011)

any rough idea on how much a blower would be? i wouldn't not need enough to get the free blower deal. the ceiling is about 100sqft.

also on something like this:
http://www.homedepot.com/Building-M...=10053&langId=-1&storeId=10051#specifications

does that imply it gives a 40sqft area a r3.7? so if i have a 100sqft and want R38 i would need roughly 25 bags of that?


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## Windows on Wash (Aug 30, 2011)

Why not blow the whole attic?

Might as well upgrade the insulation in total.

Be sure to air seal first.


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## langless28 (Nov 20, 2011)

Windows on Wash said:


> Why not blow the whole attic?
> 
> Might as well upgrade the insulation in total.
> 
> Be sure to air seal first.


It already has been updated with cellulose and air sealing. I had an energy audit and took advantage of a $2k rebate and got air sealing, r38 cellulose and blown in wall insulation for about $500 out of pocket. Unfortunately I am doing the kitchen now, I opened the rafters one by one to blow the cellulose back fom the kitchen area. There was also old batt insulation previously in the attic


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## Windows on Wash (Aug 30, 2011)

Bump it up to R-50.

Can't hurt.


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## langless28 (Nov 20, 2011)

Agreed. As to my question on blown in; is that how's it's calculated?


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## Fix'n it (Mar 12, 2012)

100sf. i think i would put roxul. then pile on what cellulose you have over the top.


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