Blow in Ceiling Insualtion as Ceiling is Installed

[SSdoxie]

I've blown insulation in couple houses I remodeled and used both cellulose and fiberglass. Used to use cellulose just becsue of the itch factor of fiberglass but cellulose needs to be thiker to get same R factor and it does settle more, especially if moisture in the attic. I reblew my attic in current house this spring using fiberglass. Owen Corning has some white tuff out now that is "no itch", low irritation. Price works out to about same with either since you need more cellulose to get same result.
I wouldn't try blowing as you put up the ceiling, with the wind coming out the blower it will push the insulation back into a pile and make it hard to cover the few sheets you put up. Plus the blower rent is usually free if you buy certain number of bags and have the blower back in 24 hrs. Just lay a couple planks up in the ceiling joist to walk or crawl on before you finish puting up the steel. Trying to balance on the joist, watch where you are blowing, then step back to the next joist has resulted in more than one foot going through the ceiling, in this case bending the steel and poping screw loose.

 

[ray66v]

Re: Blow in Ceiling Insualtion--Celluliose or Fiberglass??

Don't discount the fire barrier value of a metal ceiling. Many people mistakenly assume that fire rating is based on insulation capability. It's actually based on the resistance to burning, burning through, and transmitting heat. As a roof, 29 ga. metal is Class A rated. You would need a major fire to ignate insulation above a metal surface because it spreads the heat as it conducts it in all directions.
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The problem with steel in a fire is, it does a very good job of conducting heat. The heat from a fire rises to the ceiling, and is transmitted to the other side with almost no loss, igniting anything combustible. Not your insulation, your roof trusses, or furring used to hang the steel. Heated wood can ignite at temperatures as low as 500 degrees F. The steel also warps, and buckles as it expands from the heat, this allows fire, and superheated smoke to go through the gaps.

The problem is not so much when your working in the building, as when the fire ignites in an unoccupied building. Then, it can potentially develop quickly into a big enough fire, that a Class-A flame spread rating is not going to slow down.

I would not be surprised to quickly be able to measure temperatures above 500 degrees at the ceiling, directly above a very modest sized fire.