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Steve Genco
Posted: Jan 09, 2006 03:41 PM
Warping issues
Greetings, we are a manufacturer of roof & floor panels. Trying to move away from polystyrene pre-formed insulation blocks between the joists. We have tried to spray closed cell foam directly to the OSB and joists - in a 2-3 coat process, filling to 5 inches or so. Have noticed that we get an unacceptable warp to the OSB (crowning out opposite side of foam and joists - which is unexpected if the foam expands?? - shouldn't it become concave?). Not sure if it is poor technique - spraying too much, too fast, or some other issue. We have used this foam in our walls with little dificulty - but only spray 2 inches total there. Thanks.
Gerry Wagoner
Posted: Mar 24, 2006 11:42 AM
Correct. Heat is the issue. To much too fast too quick will cause the "bulging" that you describe. Try spraying half that amount and letting it cure between lifts. Or, use a waterbase foam. Less R & less strength is the tradeoff. We have used a 1# open cell with some success. The R-value is 4.5 per inch.

Steve Genco
Posted: Mar 28, 2006 11:39 AM
Thanks for your reply -- any idea where we can get the R-4.5 foam.

Thank you
Gerry Wagoner
Posted: Mar 31, 2006 10:25 AM
Try NH spray foam. George Spanos. He posts on here...


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