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Old 07-17-2013, 08:57 AM  
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Default Insulation stop air through crawlspace

Our electric bills have been $400 plus and I think I havefound one reason. I have a walkoutbasement that has a shop area and the shop is letting tons of outside air intothe crawl space. The exterior wall of the shop has no insulation at all and theinterior is partially insulated. In winterour main level floor is cold and summer our basement is warm. I am looking at blocking the air flow andinsulating the crawl space to the shop area. For other reasons I can not drywall the area, so I am trying my best tohelp reduce what I can.

Attached is a picture of the area

Area 1 is on the left where the studs go to all the way tothe top. My thoughts are to place thefoam board behind the studs and continue up with the fiberglass.

I understand fiberglass doesn’t block air and the foam boardwill do this. My hopes is that the combowill stop air flow and keep the temp and moisture controlled.

Area 2 is on the right where the studs stop and the crawl spaceis open. Darn pipe is there. Thinking I could manage to install 3 layers ofthe foam board to get the R up to 15.

FYI There is access to the crawl space on the other side ofthe house for repairs, so I can completely block this area off if needed.

Any suggestions would be helpful!

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Old 07-17-2013, 07:20 PM  
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You have a few things that should be addressed.
Foam board must be protected with drywall, think you will find that's true even with the fire rated stuff.
Both walls should be firestopped, so a fire in your shop can't spread rapidly thru the house. That would be adding wood or drywall on top of those wall to the ceiling.
You have plumbing on the cold side of this, so an insulted drop around the pipe would be the ansewer there.
If you shop is a garage it should be drywalled and taped to seal it up from letting auto off gasses from getting in the house.
Why can't you drywall this area?

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Old 07-24-2013, 05:29 AM  
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Don't understand what the post is about. What is with the foam board? Why do you need that? Personally i would recommend to use Roxul is better than fiber glass.
Dry wall is the obvious choice for the walls. You might insulate the floor too lot of cold come up through there.
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Old 07-24-2013, 06:21 PM  
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The crawl space must be ventilated so if you can achieve that at the same time as sealing up the interior walls then I would finish the sheathing on the other side of the open wall and insulate it with fiberglass batts just like it already is.
I think non paper face fiberglass insulation does not require dry walling but, I could be wrong on that one.
Frame in a soffit and access panel around the plumbing and duct work.
Fiberglass insulation will block air flow and should never be installed over ventilation (i.e.- soffits).
P.S.- I don't think pic #1 uploaded successfully.
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