How resilient is fiberglass insulation?

[DerbyDad03]

When I bought a roll of R-19 fiberglass insulation the other day, the guy in the orange vest had to cut open a package of 6 rolls. As he cut the plastic outer wrapping the 6 rolls expanded by a considerable amount...let's call it 50%, but the numbers don't really matter.

Then when I got home and cut open my individual roll, it expanded once again...let's say another 50%, but again the numbers don't matter.

That tells me that the manufacturer is quite happy to compress the insulation by a considerable amount for an extended period of time.

So here's my question:

If I put the 1/3 roll that I have left in one of those vacuum storage bags and compress it down as far as I can, will it bounce back to it's full size (and R value) next month, next year, next decade?

In other words, how long can insulation remain compressed before it looses it ability to perform at it's original specs?

P.S. those bags will indeed compress the insulation down by a whole bunch! BTDT, last night.

[Frank]

I wouldn't. If it were fully recoverable, the manufacturer would have supplied it under higher compression.

[hrhofmann]

[hrhofmann]

I would compress it about the same amount as the manufacturer did. The mfgr would compress it even more if it was ok to do so.

[Tegger]

DerbyDad03 wrote in news:cd5ad97e-d828-4ae5-82e8- [e-mail]:

Good question. And I don't know the answer. But I have pensees (that's French, and it doesn't mean what you think it means)...

Obviously, any deformation would have to be less than the plastic deformation point of the material being deformed. And seeing as how fiberglass insulation is, well, glass, I imagine it doesn't have the same elasticity as, for instance, spring-steel. Squeeze it too far, and you probably get a bunch of broken strands of glass.

Shipping is a big cost for items as bulky as fiberglass insulation. It would make sense that any company run by reasonably-intelligent people would have investigated the feasible limit of compressing their product so as to save shipping costs. I therefore reason that the 50% compression that you observed its probably close to that limit.

Some 20-years-ago, certain pillow and cushion manufacturers tried shipping product that had been vacuum-packed into a flat state. This was done to save shipping costs, and was supposed to be the wave of the future. The problem was, it turned out that pillows de-poofed past a certain length of time tended to stay de-poofed when eventually released from bondage. Nice idea in theory, but not in practice.

[willshak]

DerbyDad03 wrote the following:

Try just a small piece of the insulation (2' ?) in the bag and see what happens.

[willshak]

DerbyDad03 wrote the following:

Try just a small piece of the insulation (2' ?) in the bag and see what happens.

[DerbyDad03]

Try what?

I can't wait a year to see if my sample springs back to full size.

BTW...this isn't a big deal. Based on the cost of a roll of R-19 insulation, I've probably squished less than $4 worth, so if it doesn't respond when I open the bag "next year", I'll just go buy another roll.

It's more of a curiosity question, which often lead to lively discussions in this forum.