Blown Cellulose vs Blown Fiberglass Insulation

[calphi27]

Found out my back bedroom has ZERO insulation in the ceiling. It is a cookie cutter home where other models have an elongated garage and ours has a back bedroom. There is no insulation over any of it.

Anyhow went to the depot and they had the fiberglass and cellulose. Both come with machine rentals when you buy X amount. Anyone have experience with both? Looks like my area calls for R-49 in the roof!

It is only 100 square feet above the bedroom, so I could go for the roll out kind, but I might as well do the garage too. I can only get R30 with roll out unless I double it.

 

[Ebag333]

Get the roll out kind, and get as much in there as you can.

I had a bedroom that I used blow in insulation, got the cellulose kind (marketed as "green", mostly got it 'cause it's non-itchy and was cheaper). It works fine, tends to plug up the machine more than the fiberglass type. I went with this option as the roof slanted from about 3' tall on one side to 6" tall, making about half the ceiling too low for me to reach (though I could get it with the blower). If that hadn't been the consideration, I would have done roll in insulation in a heart beat.

Blow in insulation settles over time meaning you lose R value as it settles. Rolls don't have that problem.



Keep in mind that you want the facing (paper) to the inside of the house. So if you double up on the layers, your top layer will need to be unfaced.

R-49 is a little overkill, R-30 is likely more than enough. That being said, the majority of heat escapes through the ceiling so if you want to do overkill that's the place to do it.

If you have enough room, roll out an R-30 faced roll then an R-30 unfaced roll in the opposite direction. Keep in mind you do not want to compress the insulation, so only do that if you have enough room (vertically). Also check if you need to cover it, you should be fine as long as the facing (paper) isn't exposed but some areas can get picky.



The ultimate if it's available for your area is spray in foam insulation. You'll get an insanely high R value. Cost and availability are issues there, and it's not really DIY.