Open cell spray foam risk in sloped ceiling application
Would anyone have any reservations in climate zone 5 to use open cell spray foam in a sloped ceiling application? One contractor is telling me that closed cell is not an option because: the closed cell spray foam has a more intense exothermic reaction while being sprayed. More heat is produced and because the cells are closed there is no way for the heat to dissipate correctly if you overspray/fill a section. In this event the foam with trap heat in its core and it can start a fire. This does not happen with the open cell spray foam because its cells allow the heat to dissipate easier so you fill a sloped sheetrocked cathedral ceiling without concern of trapping heat. The only way to spray foam the sloped sheetrocked cathedral ceiling sections with closed cell spray foam is to remove the sheetrock so that you have direct access to the roof deck and rafters like you do in the kneewalls and unfinished attic space.
I have never read or heard of this before. Any comments would be really apprecaited.
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