Polyisocyanurate insulation and damaged
Divad
| Posted in Energy, Heating & Insulation on
I have a number of panels of polyisocyanurate insulation that have been stored for a time in less than ideal conditions. During this period of storage, the foil on the panels has been damaged, though the panels themselves are in decent shape. I would like to use the panels for wall insulation and am wondering if I can use them as they are and simply place foil over the installed panels before the paneling is put in place. If so, should the foil also be placed in the stud bay between the foil and exterior sheathing?
Thanks
_DAVID R. WARNER, JR
Replies
There are two main reasons for the foil facing.
One is simply to hold things together, sandwiching the foam for strength so it can be used without falling apart.
The other is as a reflective surface, useful in some instances, but not helpful in many others.
To make any gain from the reflective surface, it must be installed in such a way as to have about an inch of free air space immediately in front of it. When it is in direct contact with another material, the reflective surface has little value, for instance, if you were nailing it to the face of the studs on the inside, and then applying the Sheetrock right directly on top of it.
There are two things that I am aware of that cause degradation of the insulation itself. It is not clear to me whether either of these applies in your case.
One is if water has entered the insulation. This is an open celled foam and will absorb and store water leading to potential for mold growth and nearly eliminating its insulative values. If this was stored horizontally in the outdoors, with damaged foil surfaces, then you may have such sodden material.
Another source of damage to these is UV rays of the sun. If this was stored with the edges exposed, it has turned to a dark brown instead of light cream colour around the exposed edges. You will find that it is then very brittle and just by rubbing it, you will see it disintegrate.
Another point to consider is that this material is often counted on as a VB in the wall system. damage to the surface foil means that it has no integrity in that function.
If you can say more about the details of exactly what sort of damage these have and how you intend to use it in the wall, it is more likely to have better useful advice
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I seem to recall, that Poly ISo CANNOT be installed inside the studs in a residential construct. You ever hear that?Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
Well, seems to me that installing anything inside the studs would be difficult at best. ;)
If your view never changes you're following the wrong leader
Go eat your dinner, Daniel!;)
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I do it all the time - well, not all the time, but in a cold climate, that is where it belongs. In YOUR climate with more cooling days than heating days, you want that layer on the outside of the wall assenbly
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No, seriously, it had to do with toxicity of the combustion in a fire..we ( back in Pa) were prohibited from installing it except on the outside face of the studs..go figure.Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
Man, that's some news.
I did that all through my place even in the cathedral roof with up to 3 inch thick blue dow panels taper cut and hammered in to caulked spacers for the 1 1/2" airvent on the cold roof.
I did have concerns of the cutting for outlet boxes in the walls as I lit a small piece of the foam and it burnt pretty quick and nasty. Not much solace at the thought even with drywall covering.
Needless to say, no candles in the house.
sobriety is the root cause of dementia.
Not the Blue foam, nor the pink, its the PolyIso that will make the stink.Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
I knew there was toxicity in fire, but not that there were restrictions other than to cover with sheetrock. I did have one customer require No Foam of any kind in their house because of concerns over that so we used BIBBs
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From Journal of Fire Sciences:"Fire Research Institute Ministry of Home Affairs 14-1, Nakahara 3-Chome, Mitaka, Tokyo 181 Japan"Foam plastic building materials were exposed to practical fire en vironments. Toxic gases evolution from various foam plastic boards burning under fire conditions involving plywood combustion was determined. A foam plastic board as a specimen lined on one of the inside walls of a "plywood box shape" was combusted in a semi-full-scale fire test room under different air sup ply rates. CO was the most important toxicant, followed by HCN and acrolein. The difference in maximum total toxicity according to the fire test was rather small, probably because the toxicity from plywood accounted for a large portion of the total toxicity. However, the maximum total toxicity indexes of combustion gases involving rigid urethane and polyisocyanurate foams were higher than when phenolic and polystyrene foams were involved in fire tests, because a considerably great amount of HCN was produced from the above nitrogen- containing materials."For more details, you may need to buy the book "Advances in Combustion Toxicology" 378 pages, 1992 - I'm sure you'll want this for leisure reading in the commode, and only $80 from Amazon.comFrom the Homasote MSDS on Polyiso: http://www.homasote.com/MSDS/Homasote_Thermasote_MSDS_20060803.pdf"Material is flammable, not explosive.
Extinguishing Media: Water, carbon dioxide (CO2).
Special Risks: Combustion produces irritating and toxic fumes and gases, including carbon monoxide (CO) and carbon dioxide (CO2). Dust may explode at concentrations greater than 40 grams dust per cubic meter of air.
Under certain fire conditions, the polyisocyanurate foam component can generate combustible gases creating rapidly spreading, high intensity flames and dense, black smoke.
Special Protective Equipment: Self contained breathing apparatus is recommended"
"However, the maximum total toxicity indexes of combustion gases involving rigid urethane and polyisocyanurate foams were higher than when phenolic and polystyrene foams were involved in fire tests, because a considerably great amount of HCN was produced from the above nitrogen- containing materials."
So.I guess there is validity to my presumption?Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
Thanks. The panels were stored outside but covered so protected from water and most sunlight. Some of the edges are brownish, but beyond the first half inch or so they look OK. Mostly the damage is confined to rips in the foil_DAVID R. WARNER, JR
If you are wanting to make use of the foil as a vaporbarrier you will want to use foil tape adhered over the damaged areas as well as using the tape for sealing the seams of the insulation panels when placed together.
sobriety is the root cause of dementia.
That's one idea, but if it is all peckered up with lots of holes penetrating the surface, it would be better to just run plastic sheet over it, all of course depending on how the whole wall is detailed. We don't want a VB on both sides of the wall.
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