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Do thick installations still develop shrinkage gaps, or has the industry done something to rectify that problem?
Background: In the early days of evaluating installed, conventional, 2 lb., spray-applied, polyurethane insulation, it was common to find shrinkage gaps (e.g., 12-15% gapping) at 3.5″ studs (e.g., dislocation of the foam from the stud thereby allowing an air gap). Thus the thick installation of foam would appear to act a bit like a cake, shrinking as it cured, and pulling away from its containment. Skimcoat (0.75-1.5 inches) applications did not appear to suffer the separation cracking, perhaps because it was a thinner application.
Cameron
Replies
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Do thick installations still develop shrinkage gaps, or has the industry done something to rectify that problem?
Background: In the early days of evaluating installed, conventional, 2 lb., spray-applied, polyurethane insulation, it was common to find shrinkage gaps (e.g., 12-15% gapping) at 3.5" studs (e.g., dislocation of the foam from the stud thereby allowing an air gap). Thus the thick installation of foam would appear to act a bit like a cake, shrinking as it cured, and pulling away from its containment. Skimcoat (0.75-1.5 inches) applications did not appear to suffer the separation cracking, perhaps because it was a thinner application.
Cameron