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Message: <blockquote data-quote="raider" data-source="post: 77116" data-attributes="member: 353">open cell has really no good application north of kansas in my opinion... it has an r value, depending on blend, of bout r3.5 per inch, while closed cell is bout r7... open cell gives no perm rating, or vapor barrier... in zones south of here you can hit building code standards with it in terms of r value, but not up here... r3.5 in a 4 (actually 3 1/2") wall cavity only gives you r14, when you need r21 to hit code... in a 2x6 wall (5 1/2") you can hit r19.5, which is still short even with a full cavity fill, which is how it is normally applied... open cell is normally applied full cavity, and then shaved down to be even with the studs... it is like a sponge material you can easily pull out with your hands, and trims very easily... it will absorb water, and needs a vapor barrier...closed cell is normally applied at 3", for r21, in wall cavities, and can be sprayed down on rock in ceilings to seal, with a layer of blow in to meet code, or applied directly to the roof sheeting (hot lid)... it cures very hard, giving a 400% increase in racking strength (structural strength), and has a perm rating (vapor barrier) usually at 1" or less... the only thing open cell should be used for up here would b for sound deadening in interior walls such as bedroom or bathroom, or between floor joists, but fiberglass works just as well... for sound deadening, pack the fiberglass tight... in 6" walls, pack in a 5" (r19) unfaced batt... i will say open cell finds it's way up her from time to time... some contractors up here from down south have tried to peddle it as "spray foam" instead of open or closed cell, and they normally will not tell you what it is... b careful... if the price seems too good to be true, it most likely is... open cell should cost bout 20% of closed cell...</blockquote>

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