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Brian Rener Posted: Sep 23, 2007 12:17 PM	Addition in Northern Illinois I am currently designing a 700 single story addition to my home in far northern Illinois. The addition is a combination of a family room and bedroom. It will be over a sealed crawlspace (mini basement type). I plan to use spray foam and have an unventilated attic. My local town requires R19 in walls and R38 in ceiling. That is fine with me - and I am willing to exceed it. I want the space to be as energy efficient as possible. Wiling to consider 2x6 wood frame walls and 2x12 ceilings. My wife has asthma and chemical sensitivities. Would like not to worry about Formaldehyde, VOC's, etc... Would kind of specifications for the spray foam would you recommend?
David Lenaker Posted: Sep 24, 2007 04:14 PM	You would want a 2lb closed cell foam. Has a vapor retarder at 2 1/2 in. and a air barrier. That will make for a healthier indoor evironment. Stick with R-19 wall. And the R-38 ceiling is a little over kill and it will be extremely expensive because thats 6in of foam. R-30 4.5 in. is more than sufficient. Your foam contractor will have to talk to title 24 and have them recal your roof r value since your choose to use foam.
Brian Rener Posted: Sep 25, 2007 11:02 AM	Thanks! I am going to specify 2lb InsulStar SPF. R value 7 per inch. Sticking with 2x4 walls would give me more than R19 in the walls if needed. The roof insulation of R38 is what our code wants in my town and complies with Energy Star Guidelines.
Gerry Wagoner Posted: Sep 30, 2007 09:05 PM	Insulstar is one of the toughest foams on the market. Good product.

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Comments

Brian Rener

Posted: Sep 23, 2007 12:17 PM

Addition in Northern Illinois

I am currently designing a 700 single story addition to my home in far northern Illinois. The addition is a combination of a family room and bedroom. It will be over a sealed crawlspace (mini basement type). I plan to use spray foam and have an unventilated attic.

My local town requires R19 in walls and R38 in ceiling. That is fine with me - and I am willing to exceed it. I want the space to be as energy efficient as possible. Wiling to consider 2x6 wood frame walls and 2x12 ceilings.

My wife has asthma and chemical sensitivities. Would like not to worry about Formaldehyde, VOC's, etc...

Would kind of specifications for the spray foam would you recommend?

David Lenaker

Posted: Sep 24, 2007 04:14 PM

You would want a 2lb closed cell foam. Has a vapor retarder at 2 1/2 in. and a air barrier. That will make for a healthier indoor evironment. Stick with R-19 wall. And the R-38 ceiling is a little over kill and it will be extremely expensive because thats 6in of foam. R-30 4.5 in. is more than sufficient. Your foam contractor will have to talk to title 24 and have them recal your roof r value since your choose to use foam.

Brian Rener

Posted: Sep 25, 2007 11:02 AM

Thanks!

I am going to specify 2lb InsulStar SPF. R value 7 per inch. Sticking with 2x4 walls would give me more than R19 in the walls if needed. The roof insulation of R38 is what our code wants in my town and complies with Energy Star Guidelines.

Gerry Wagoner

Posted: Sep 30, 2007 09:05 PM

Insulstar is one of the toughest foams on the market. Good product.

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