Dense packed cellulose in 2x4 stud walls

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mhylmz

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Has anyone tried dense-packing cellulose insulation in walls using Home Depot/Lowes DIY cellulose blowers ?

I am trying to decide between RockWool R15 batts and dense packing cellulose, and I am not sure whether a stronger blower is needed for cellulose.

Since I opened up the walls, I am closing all possible air leak points using caulk/3M flashing tapes ( http://www.amazon.com/gp/product/B00D9HB03C/?tag=skimlinks_replacement-20 ), and fire putty sheets around electrical outlets ( http://multimedia.3m.com/mws/media/201513O/3mtmfire-barrier-moldable-putty-pads-mpp-product-data-sheet.pdf ).

I don't want to use spray foam. First, it burns easily. Second, closed cell foam is not a good sound isolation material wrt other options.
 
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Sparky617

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Polyiso has a very good fire performance rating. http://www.polyiso.org/

Are you putting the insulation in before you put the wallboard back up? That requires a different technique than blowing into the cavity.

Into a cavity with sheetrock on the wall.
[ame="https://www.youtube.com/watch?v=jd5FZ8ZWRAc"]https://www.youtube.com/watch?v=jd5FZ8ZWRAc[/ame]

Open cavity installation. About 6 minutes into the video
[ame="https://www.youtube.com/watch?v=RgTOQwC6B4U"]https://www.youtube.com/watch?v=RgTOQwC6B4U[/ame]
 

mhylmz

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This is an exterior wall, and the outside part of the wall is still there. I just removed the old plaster wall from inside.

This document shows all the chemicals they add to the cellulose:
http://www.greenfiber.com/images/technicaldocuments/730201573119AMBlended Stabilized Formula.pdf

Contents:
85% newspaper
10-12% Boric Acid H3BO3, Ammonium Sulfate (NH4)2SO4
Not more than 1% Mono-Ammonium Phosphate NH4H2PO4
Not more than 1% Zinc Sulfate ZnSO4-H2O #7746-19-7
Up to 2% Amylopectin
Up to 2% Distillated Mineral Oil

Boric acid, ammonium sulfate, mono-ammonium phosphate are corrosive to steel by themselves (All my electrical is in steel conduits). I am not sure how this mixture formula behaves when it is wet. Zinc sulfate can be used for steel corrosion protection. Some of it may be neutralizing each other.

I guess the best test would be to get a bag of cellulose insulation, make it wet, and put a steel pipe in it, let it stay there a few weeks and check the result. Probably not worth the trouble for wall insulation. I will just use rockwool, but I may run the test before adding loose cellulose to my attic.
 

Sparky617

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Where are you located and what are your average winter temperatures? What R-value is code for your area?

The water evaporates out pretty quickly. If you don't add the water there is no way it will stay up until you get it sheet rocked. I've seen installations on TV shows where they apply a mesh over the stud bays to hold it in and they blow it in like the first video I linked. The Boric acid is put into the cellulose to make it fire retardant.
 

mhylmz

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I live in San Francisco Bay Area. The code is R13 for walls. I decided to go with rockwool for the walls. Lowest temps are low 30's for winter. Sometimes 30-31, but rarely.
 

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