Fiberglass insulation

[fishhead]

I finally got most of the fiberglass insulation installed in my first 2 walls. All but one of the pieces had to be custom cut because of the way the builder placed the studs and random 2x4's.

The 16" insulation fluffed up pretty well but the 24" insulation was only about 2" thick. I tried to fluff it up by shaking it like a rug and by pulling the insulation away from the paper backing but it just tore so I quit.

Will gravity eventually cause the insulation to pull away from the backing and fill the cavity?

[Windy in Kansas]

Originally Posted by fishhead

Will gravity eventually cause the insulation to pull away from the backing and fill the cavity?

No....

[fishhead]

Then how do you get it to fluff up? I shook it like a rug and tried tugging on it from the glass side but neither worked.

I've read that if possible you unroll it a day or 2 ahead of time to allow it it to fluff by itself. That's why I was hoping it would do the same in the cavity and that gravity would help.

The manufacture date in late October so it's new stuff.

[ovendoctor]

Originally Posted by fishhead

I finally got most of the fiberglass insulation installed in my first 2 walls. All but one of the pieces had to be custom cut because of the way the builder placed the studs and random 2x4's.

The 16" insulation fluffed up pretty well but the 24" insulation was only about 2" thick. I tried to fluff it up by shaking it like a rug and by pulling the insulation away from the paper backing but it just tore so I quit.

Will gravity eventually cause the insulation to pull away from the backing and fill the cavity?

wat r factor are ya using

Doc.

[fishhead]

R-13. The studs are rough sawn full sized 4" deep.

[gobug]

Fluffed up fiberglass will do nothing for you, except maybe coat your skin and clothes due to the process. It will not improve insulation. Fiberglass insulation allows air to move through. If you fluff it, and there are any air leaks in the inner or outer walls, you will have R value =0. If you compress it, it will be similar to other fiberglass compressed insulation products. A vapor barrier, and paper coated fiberglass batt, will help, but if the outside is not airtight it will not be the best insulation.

[arabian knight]

R-13 is what I have put up and at Most it is 3 inches thick. I just went and put a measure on it.~! And this is laying up and down and not flat. SO if it is ONLY R-13 That is IT. You can not get anymore thickness out of it.
Should have been a high R value, for a fluffier and thicker insulation.

[Ross]

The 2 inch stuff is likely R12 the thicker stuff R20. Kinda depends on the maker for the exact R values

[fishhead]

The bags said R-13 and 3 1/2". I've got 1" blue foam on the outside under the siding so there shouldn't be much wind problem.

[Dead Rabbit]

when packaged its packed tight.

it will be fine. no need to try and fluff it. your just making a mess in the air that your inhaling.

ive been told that soon, they will get away from R-13 and will be going to R-15 as minimal R value for walls. but ive been hearing that for 5 yrs. so its probably just talk.

[fishhead]

Some of the cavities in the wall had zero insulation and most had insulation stapled flat. I should see a huge improvement.

Too bad I didn't do that 20 years ago and already saved 5x what I just spent.