# Just wondering about adding Insulation to a flat roof home?



## ionized (Jun 8, 2012)

What is your climate like?


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## jklingel (Dec 21, 2008)

is the foam on the outside or inside of the roof sheathing?


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## Windows on Wash (Aug 30, 2011)

Need more details.


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## rodm1 (Dec 27, 2009)

I'm in Michigan temps run from 20° to about 90° some times lower and higher but that is generally what you can expect. 

The foam is over top of the old tar roof (Sheathing, Tar, Foam, last EPDM).

Anything else you need to now?

Thanks,

Rod


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## Windows on Wash (Aug 30, 2011)

So the venting is under the old sheathing at the original level then?

If that's the case, you are limited by insulation depth because you don't want to block off that venting. You can blow in more insulation in that interstitial space but don't block the vents.


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## rodm1 (Dec 27, 2009)

Windows on Wash said:


> So the venting is under the old sheathing at the original level then?
> 
> If that's the case, you are limited by insulation depth because you don't want to block off that venting. You can blow in more insulation in that interstitial space but don't block the vents.




Correct, How close could I get to the sheathing? I believe I have about 7 inches of air space.


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## Windows on Wash (Aug 30, 2011)

Within an inch and the CC SPF has to be done in lifts.

I think we need some pictures of the attic because (no offense) the message is a bit jumbled.


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## rodm1 (Dec 27, 2009)

I'm afraid photo's won't be helpful there isn't anything to really see (no way to see the construction). If I add insulation it probable would be blown in insulation.


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## Gary in WA (Mar 11, 2009)

http://www.buildingscience.com/docu...archterm=attic+fiberglass+batts+in+flat+attic

Gary


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