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briant73 Posted: Oct 11, 2016 03:44 AM	Attic Insulation questions Posted this in homeowner forum but no responses to my query so thought I'd try here (I hope that is ok) Attic insulation questions New user here hoping for some help and advice on getting Attic better insulation. I live in the NW Pennsylvania region and since buying my house have had ice dams and icicles frequently in the winter on my home. I was told three things may be causing the issues with ice dams at the edges - attic ventilation, insulation, and low pitched roof. So I have asked various contractors and insulation companies their ideas to fix this and most come back with the same two suggestions 1) 7-8" inches of Open cell Spray foam the underside of the roof deck. Allowing the attic to be a conditioned space accessible for storage and easy access if needed. 2) Add soffit vents, foam rafter vents, possibly more roof vents and blown in insulation to the attic. This would take away the attic as storage and make access only when really necessary. All the insulation people said for cost option 2 would be less expensive but all said spray foam would be the best option. I actually did add soffit vents and the foam rafter vents last fall to see what would that do since the cost was minimal and the results weren't much different. My questions are the following: 1) Will open cell spray foam be the best option (performance and longevity) as the insulation contractors suggest? I'm ok with spending the money to do things right. 2) Each contractor uses different open cell products (Foamsulate, SEALECTION 500, ICYNENE ) which all seem similar performance to me , is that actually the case though? 3) Some recommend 7" depth under the roof deck where another say's up to 8" - should I care about the extra inch of foam or doesn't it matter? Would it be worth it to ask for even more than 7-8"? Thanks!
mason Posted: Oct 11, 2016 12:22 PM	Sorry for the delayed reply. We just got back in town after evacuating fro Hirricane Mathew. We still don't have internet service yet. In order to stop ice damming you need to prevent warm air from the interior walls of your house from reaching the underside of your roof deck. This can be accomplished with either a vented or invented attic configuration. The main goal is to seal the outside of the interior wall of the house from the attic space to keep that warm air from reaching the attic space. I have a lot of articles relating to this subject but cannot load them up at this time. In the meanwhile check out this website and download articles on ice damming, and invented attics. Building science.com You can use half pound foam but in colder climates would need a vapor retarder over the foam. Check out technical documents on unvented and vented attics at sprayfoam.org as well.
briant73 Posted: Oct 11, 2016 06:26 PM	Thank you for the response - I hope all is OK after the storm. The building science site had so many articles and a lot of them outside my knowledge and experience. I have talked to several contractors who suggest going to an unvented attic saying they want to spray the underside of the roof deck with 7-8" of open cell foam, none have mentioned a vapor retarder that I can tell, in fact one said no need for one. One says 7" inch is fine and another says 8". So should I insist on a vapor retarder and also would the difference between 7 to 8" of foam be worth spending more to get the 8"?
briant73 Posted: Oct 17, 2016 03:56 AM	Hope all is well after the storm. Figured I'd check in again since I'm close to making a decision but have a few questions - Have two different companies quoting for spray foam, one is recommending 7" and the other is 8". The 7" quote is less expensive and when I asked about 8" that installers price was still less than the other companies but the installer felt going to 8" was not needed because of diminishing returns and to stick with 7". Wanting to get this right the first time what would you say to that? Also when I asked about vapor retarder neither company felt it was needed, should I push for that or at least for an explanation why not? Thanks!
briant73 Posted: Oct 17, 2016 04:07 AM	Meant to add that's for open cell spray foam.

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Comments

briant73

Posted: Oct 11, 2016 03:44 AM

Attic Insulation questions

Posted this in homeowner forum but no responses to my query so thought I'd try here (I hope that is ok)

Attic insulation questions
New user here hoping for some help and advice on getting Attic better insulation. I live in the NW Pennsylvania region and since buying my house have had ice dams and icicles frequently in the winter on my home. I was told three things may be causing the issues with ice dams at the edges - attic ventilation, insulation, and low pitched roof. So I have asked various contractors and insulation companies their ideas to fix this and most come back with the same two suggestions
1) 7-8" inches of Open cell Spray foam the underside of the roof deck. Allowing the attic to be a conditioned space accessible for storage and easy access if needed.
2) Add soffit vents, foam rafter vents, possibly more roof vents and blown in insulation to the attic. This would take away the attic as storage and make access only when really necessary.

All the insulation people said for cost option 2 would be less expensive but all said spray foam would be the best option. I actually did add soffit vents and the foam rafter vents last fall to see what would that do since the cost was minimal and the results weren't much different. My questions are the following:

1) Will open cell spray foam be the best option (performance and longevity) as the insulation contractors suggest? I'm ok with spending the money to do things right.
2) Each contractor uses different open cell products (Foamsulate, SEALECTION 500, ICYNENE ) which all seem similar performance to me , is that actually the case though?
3) Some recommend 7" depth under the roof deck where another say's up to 8" - should I care about the extra inch of foam or doesn't it matter? Would it be worth it to ask for even more than 7-8"?

Thanks!

mason

Posted: Oct 11, 2016 12:22 PM

Sorry for the delayed reply. We just got back in town after evacuating fro Hirricane Mathew. We still don't have internet service yet. In order to stop ice damming you need to prevent warm air from the interior walls of your house from reaching the underside of your roof deck. This can be accomplished with either a vented or invented attic configuration. The main goal is to seal the outside of the interior wall of the house from the attic space to keep that warm air from reaching the attic space. I have a lot of articles relating to this subject but cannot load them up at this time. In the meanwhile check out this website and download articles on ice damming, and invented attics. Building science.com

You can use half pound foam but in colder climates would need a vapor retarder over the foam. Check out technical documents on unvented and vented attics at sprayfoam.org as well.

briant73

Posted: Oct 11, 2016 06:26 PM

Thank you for the response - I hope all is OK after the storm.

The building science site had so many articles and a lot of them outside my knowledge and experience. I have talked to several contractors who suggest going to an unvented attic saying they want to spray the underside of the roof deck with 7-8" of open cell foam, none have mentioned a vapor retarder that I can tell, in fact one said no need for one. One says 7" inch is fine and another says 8".

So should I insist on a vapor retarder and also would the difference between 7 to 8" of foam be worth spending more to get the 8"?

briant73

Posted: Oct 17, 2016 03:56 AM

Hope all is well after the storm. Figured I'd check in again since I'm close to making a decision but have a few questions -

Have two different companies quoting for spray foam, one is recommending 7" and the other is 8". The 7" quote is less expensive and when I asked about 8" that installers price was still less than the other companies but the installer felt going to 8" was not needed because of diminishing returns and to stick with 7". Wanting to get this right the first time what would you say to that?

Also when I asked about vapor retarder neither company felt it was needed, should I push for that or at least for an explanation why not?

Thanks!

briant73

Posted: Oct 17, 2016 04:07 AM

Meant to add that's for open cell spray foam.

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