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Author	Comments
Dave Strnad Posted: Nov 19, 2006 08:50 PM	Closed Cell Thickness I know what the manufacture says, I know what I would put in, but every job I have done that has been 2x12 rafter construction the homeowner wants 6" put in. I am always hesitant because the maximum recommended is 4", but at the same time it's hard to talk someone out of more foam. Also local codes require an r-38 and many SPF contractors put r-38 on the bid/invoice regardless of how many inches they put in. The 6" would get me that without question. Should I put in 6" if I can sell it, or should I only apply to 4" and call it an R-38 like the other guys. Any Thoughts Thanks
Aaron Scurlock Posted: Nov 20, 2006 09:09 AM	From what I understand, the 4" limit is because of the heat created by the reaction. If you did...say 3" and 3", wouldnt this solve the problem of heat buildup?
Dave Strnad Posted: Nov 20, 2006 09:45 AM	I know about the heat issue, I only apply 1.5 - 2" per pass. I thought that 4" was all that the product was tested for, because typically there is no need for more than that. Is anyone out there applying closed cell to 6"? Also what are you telling customers when you apply to less than required R-values, regardless of it being a better product? Are you putting the minumum required on the bid/invoice to cover yourself?
Melvin Chandler Posted: Nov 20, 2006 11:00 AM	My understanding is that it's only been tested to 4" in most cases but plenty of people spray it more than that. There's just not enough good hard foam info out there. What I would do is tell the customers I'll give them what they want and do a hold harmless for spraying over the recommended max.

Author

Comments

Dave Strnad

Posted: Nov 19, 2006 08:50 PM

Closed Cell Thickness

I know what the manufacture says, I know what I would put in, but every job I have done that has been 2x12 rafter construction the homeowner wants 6" put in. I am always hesitant because the maximum recommended is 4", but at the same time it's hard to talk someone out of more foam. Also local codes require an r-38 and many SPF contractors put r-38 on the bid/invoice regardless of how many inches they put in. The 6" would get me that without question. Should I put in 6" if I can sell it, or should I only apply to 4" and call it an R-38 like the other guys. Any Thoughts

Thanks

Aaron Scurlock

Posted: Nov 20, 2006 09:09 AM

From what I understand, the 4" limit is because of the heat created by the reaction.

If you did...say 3" and 3", wouldnt this solve the problem of heat buildup?

Dave Strnad

Posted: Nov 20, 2006 09:45 AM

I know about the heat issue, I only apply 1.5 - 2" per pass. I thought that 4" was all that the product was tested for, because typically there is no need for more than that. Is anyone out there applying closed cell to 6"? Also what are you telling customers when you apply to less than required R-values, regardless of it being a better product? Are you putting the minumum required on the bid/invoice to cover yourself?

Melvin Chandler

Posted: Nov 20, 2006 11:00 AM

My understanding is that it's only been tested to 4" in most cases but plenty of people spray it more than that. There's just not enough good hard foam info out there. What I would do is tell the customers I'll give them what they want and do a hold harmless for spraying over the recommended max.

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