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-   -   batt insulation and blown in (http://www.diychatroom.com/f103/batt-insulation-blown-161817/)

langless28 11-01-2012 09:19 AM

batt insulation and blown in
 
i am redoing my kitchen. i pushed back the blown in insulation in the attic above the kitchen to redo sheetrock, add recessed lights etc. i will be putting up faced batt insulation and was wondering if its a good idea to rake/blow the blown in insulation back on top afterwards. specifically fill in the areas right around all the recessed lights (total 7) they are 5" halo's and are IC rated and the blown in is of the recycled newspaper/fire retardant type stuff.

Gary in WA 11-04-2012 05:41 PM

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

Gary

Windows on Wash 11-04-2012 07:10 PM

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.

langless28 11-04-2012 07:56 PM

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.

Fix'n it 11-04-2012 08:24 PM

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

langless28 11-04-2012 08:32 PM

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?

Fix'n it 11-04-2012 09:01 PM

Quote:

Originally Posted by langless28 (Post 1044915)
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.

Gary in WA 11-04-2012 09:38 PM

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

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

Cellulose ceiling sag; http://www.energyguide.com/library/E...SubjectID=8375

Check with local AHJ for required poly with your State Energy Code; http://www.ecohomemagazine.com/energ...rfriendly=true

Gary

Fix'n it 11-04-2012 10:37 PM

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.

langless28 11-06-2012 06:40 AM

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-Ma...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?

Windows on Wash 11-06-2012 08:16 PM

Why not blow the whole attic?

Might as well upgrade the insulation in total.

Be sure to air seal first.

langless28 11-06-2012 08:44 PM

Quote:

Originally Posted by Windows on Wash (Post 1046285)
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

Windows on Wash 11-06-2012 08:46 PM

Bump it up to R-50.

Can't hurt.

langless28 11-06-2012 08:54 PM

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

Fix'n it 11-06-2012 08:55 PM

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


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