Polyisocyanurate Foam???

[WStayton]

Hi Guys!

  I bought some used foam insulatioin "planks" to cut down to use for the insulation in the area that is going to house my generator/boiler/hot-water-storage, thinking that is was plain old "hot-cup" polyurethane foam, but after picking it up and srot-of testing it, I think it may be polyisocyanurate!!!

  First the background - I am an inveterate CraigsList reader, and, a couple of months ago, I saw some 4' x 8x x 3" used foam advertised for $15 a sheet - thinking it MIGHT be cheap polyiso, I email the seller and asked him what type it was.  His return email was that he had no idea, because he had rescued it from the roof replacement of a local school, where it was going to be scrapped, and had used what he wanted and was now trying to sell what was left.  I return emailed him that if it was polyiso, I wanted 12 sheets.  A long back and forth ensued and he, finally, could not determine what  type it was, so I thanked him for his trouble and wrote it off.

  A week ago the seller re-contacted me and asked me if I could use any of the foam at a "real good price".  So, I figured out what it was going to cost me to do the equipemtn room in 3.5" fibergalss, translated that into 4" x 8" sheets and offered him $5.00 a sheet for 50 sheets, subject to inspection.  We hemmed ad hawed and settled on $6.00 a sheet - which I figured was okay foir R-21 insulation!

  So, this weekend I went and picked some of it up - 18 sheets per truck load in my Dakota was all I thought I should try to carry - weight wasn't a problem but the huge "face" of the load meant that I drove home, nearly a hundred miles, at 55 mph!  <grin>

  Anyhow, the foam was a plae yellow color and faced on both faces with some sort of tarpaper-like stuf that is well and truly glued to it.  The texture is very grainy, not at all like any polyurethane foam I have every seen/handled.  So, with my curiosity piqued, I took a small chunk of it and dropped it into boiling water, where I left it to boil for fifteen minutes and, lo and behold, there was no softening or other change AT ALL!!  To make sure of what I was looking at, I dropped in a small piece of known polyurethane from a coffe cup and it, almost instantly truned into a sticky mess!!!

  So, oh great source of all knowledge, is there any other test I should do, to confirm that it is polyiso before I gamble off to insulate tanks with it???

  Anybody with any ideas, please, you are hereby solicited to speak!  <grin>

  Awaiting with baited breath!

Regardz,

Wayne Stayton

[TimSR2]

sounds like great insulation at a good price.  ? Am I missing something here....

[DanG]

I've glommed on to used roof insulation panels before - wanted to insulate the first two feet below grade on the limestone foundation in my 1915 farmhouse but discovered the chipmunks and mice would've ended up tunneling deluxe condos in it so tossed them.

I've seen the coarse foam, it especially gets 'unglazed' with age. Know they project only 80% of the initial R rating after 10 years so ends up R-5 per inch with used polyiso foams, and probably 80% of R-5 then in another 10 years, etc.. Depending on the roof build-up it came out of, and if it was stacked outdoors after removal, it might benefit from racking it like green lumber in a protected dry air-space environment so some of the permeated moisture has a chance to chase away.

With overlapping seams and maybe an air-gap with reflective barrier in perfectly sealed air space compartments you could be storing ice all summer if you wanted too

[WStayton]

Hi Guys!

  Thanx for the insights . . .

  What I'm really wanting to know is "Is there something else I ought to do to confirm that it IS polyiso, before I slap it into the sides/bottom/top of the tanks?"

  I understand that it doesn't have the full R value as it ages, but it still beats the crap out of Fiberglass and it doesn't melt like polyurethane and it is CHEAP (my middle name!  <grin>)

  So is there anything else that I need to do to confirm that it IS Polyiso before I start hammering and sawing, or am I good-to-go with what little testing I have done???

  Again thanx for the input!

  Oh, and the seller still has about 150 sheets of the material if anybody is willing to go to North Central New York State to recover it!

Regardz,

Wayne Stayton

[fabricator]

I work with roofers all the time if it is pale yellow with felt on both sides it IS polyiso, that is industry standard for flat roof insulation.

[WStayton]

fabricator:

  Thanx!!  That was the answer that I was looking for!

  Gee, sometimes you get lucky!  <grin>

  I'm going to keep reading CraigsList, for sure!

Thanx a lot for the info!

Regardz,

Wayne Stayton

[fabricator]

No problem.

[rcavictim]

I work with roofers all the time if it is pale yellow with felt on both sides it IS polyiso, that is industry standard for flat roof insulation.

Felt??  Do you mean tarpaper? I might use felt to line the case that holds my eyeglasses.  I sure wouldn't use tar paper.

[vdubnut62]

 RCA, here in the Southern US especially, felt and tarpaper are used interchangeably. It just depends on context as to which description applies.
Yeah, I know you gotta be raised here to glom on to  some things.
Ron.

[fabricator]

I work with roofers all the time if it is pale yellow with felt on both sides it IS polyiso, that is industry standard for flat roof insulation.

Felt??  Do you mean tarpaper? I might use felt to line the case that holds my eyeglasses.  I sure wouldn't use tar paper.

Yeah, in the roofing business felt paper generally comes rated as 20,30,40 etc pound felt, it's basically heavier than what would be considered tar paper, but felt paper is impregnated with tar or a number of different things.

[DanG]

Felt - They use a roll stock of felt-like recycled cardboard, sawdust and fiberglass and dip it in asphalt to make roofing-felt, so the "felt" on the foam board lets roofing tars and adhesives get a bite to glue it down without the need for any (or many) perforations of mechanical fasteners to build-up the finished roof.

A roofing felt is different from tar-paper which is heavy kraft paper & asphalt - olden times the felt was rag fiber and held more asphalt...

[rcavictim]

Felt - They use a roll stock of felt-like recycled cardboard, sawdust and fiberglass and dip it in asphalt to make roofing-felt, so the "felt" on the foam board lets roofing tars and adhesives get a bite to glue it down without the need for any (or many) perforations of mechanical fasteners to build-up the finished roof.

A roofing felt is different from tar-paper which is heavy kraft paper & asphalt - olden times the felt was rag fiber and held more asphalt...

Thanks for the edumecation guys!  My appreciation is heart felt!   

[fabricator]

OMG

[Lloyd]

Actually tar paper and felt are 2 different products, used for 2 different needs.

Tar paper is made as a paper with short fibers impregnated with an emulsion typically asphalt based.

Felt aka Irish/Flax Felt or Ships Felt is made as a fabric using long jute fibers, also impregnated with an emulsion, most times asphalt based.

Irish/Flax Felt is flexible(like fabric), as apposed to paper felt which while flexible, doesn't do well when it needs to move in 2 directions at the same time(tends to buckle when required to move in 2 directions at once)..

It's ok to flash a moving joint with felt, but not with paper. You can tear paper but not felt.

just though some might like to know the diff.

Lloyd

[rcavictim]

It is amazing the practical stuff one can learn here!