Tips for blowing in attic insulation. Should I pack it a little?

[Dmitry]

Hi, I'm planning on blowing in fiberglass insulation this weekend. Everything is pretty clear about it except one thing. i understand that blown insulation is going to settle. should I compress it lightly it tight spaces may be? Some say it will loose R value, some say it will help in a long run. I'm not talking about pounding it. Just tapping to fill tight spaces.
Thanks.

 

[semipro]

I'd be inclined to pack it just enough to get rid of any voids larger than a golf ball.
I have no experience with loose fiberglass just cellulose. I don't recall having to pack the cellulose at all to remove larger voids.

 

[woodgeek]

The compression reduces Rvalue thing is a confusion. Most times compression increases R-value per inch, it just reduces inches more (for a fized amount of material). With FG batts, I often find that the one size thicker batt costs almost the same amount, and then I compress it slightly into the space....and get (slightly) higher R-value than the thinner batt would have had.

You prob already know this, but with blown you just try to go for post settling thickness....if you want 12", blow in 14.

I guess you are asking about narrow eave/soffit areas? Yeah....don't be afraid to pack it in there a little...a little extra R-value from the packing would be good, you will settle less, and the fraction of the job is low enough that the increased material cost is negligible.

 

[Dmitry]

The compression reduces Rvalue thing is a confusion. Most times compression increases R-value per inch, it just reduces inches more (for a fized amount of material). With FG batts, I often find that the one size thicker batt costs almost the same amount, and then I compress it slightly into the space....and get (slightly) higher R-value than the thinner batt would have had.

You prob already know this, but with blown you just try to go for post settling thickness....if you want 12", blow in 14.

I guess you are asking about narrow eave/soffit areas? Yeah....don't be afraid to pack it in there a little...a little extra R-value from the packing would be good, you will settle less, and the fraction of the job is low enough that the increased material cost is negligible.

Thank you, that's a good advice.totally makes sense and lines with what I've read on a subject .

 

[Highbeam]

In other words, the more compressed it is the better for a given depth.

 

[sportbikerider78]

Make sure you don't block your soffit vents.

 

[EatenByLimestone]

Fg settles more than cellulose. I'd blow it much thicker than you p!anned. At least 3" more. The plus with blown fg is hardly any cleanup!