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coating foilbacked insulation Post New Topic | Post Reply

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tom johnson
Posted: Apr 11, 2007 07:53 AM
coating foilbacked insulation
Hello,
our company is looking at purchasing a turnkey for our own use to re-insulate our exsisting buildings.
My question is, is it possible to spray right on top of the exsisting foil backed insulation (ceilings and walls) or do we need to tear out? It is my understanding that the polyurethane will stick to most anything but, I would like to get an idea if it is possible from you seasoned veterans out there. Thanks in advance for any resopnses!

tom
Posted: Apr 11, 2007 10:01 AM
We use the foil-faced foam for overspray protection on roof projects. The foam always sticks to it and we cant scrape it off. if it was my shop i would do it.

Im not a veteran though, i have only sprayed for 2 years.

-aaron
tom johnson
Posted: Apr 11, 2007 10:51 AM
thanks Aaron. I guess my concern is will it support itself when applied to the ceiling? I am kind of leaning towards having to remove the foilbacked insulation and spraying on the roof sheeting but, if we can save some labor I think it would be well worth it - approximatly 100,000 sq ft of shop!

thanks again,
tom
Posted: Apr 11, 2007 12:03 PM
ooooohhh. is this the flexible bubble wrap insulation? We have sprayed that type as well, but the purlins were on 2' centers. We had to spray a 1/2" pass and let it harden, then follow up with an addtional 2 inches. the 1/2" pass made the foil rigid without warping it.

again, if it was my shop id do it. 2-3" of closed cell foam is pretty strong and structurally sound.

-aaron
tom johnson
Posted: Apr 11, 2007 12:29 PM
this is actually the batt type insulation with the foil glued to it similar to kraft paper/ vapor barrier used in most commercial applications. Our perlins are 60" on center and the insulation is sandwiched between the perlins and roof sheets, so we may have to strip the insulation of anyways. Just curious if there was anyone out there that has run across this situation before and what they have done.

We may just do a trial run like you mentioned with the varying layers or coats, and see what kind of results we have.

Once again thanks for the imput! This forum has really been an asset to me!

tom
Posted: Apr 11, 2007 09:41 PM
Tommy,
Tear out the existing insulation and spray the foam to your sheathing.
Posted: Apr 12, 2007 01:03 AM
foam should go down first,,
so yank it out...
and get the foam against the substrate..

you would be greating an "air space" between
the foam and the substrate if you leave the glass...
any moisture,gross or vapor, that gets between the foam and the substrate will be "trapped" in this airspace,,,to condensate,,and allow all the nice things that a wet environment promotes to happen..
tom johnson
Posted: Apr 12, 2007 07:56 AM
some very good points that have slipped under the radar....thanks a million guys! I'm glad to have a direction then we will be able to budget for the labor to take it out.

Take care all and thanks again for the input!

tom

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