Insulation, Radiant and Vapor Barriers - open space

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mikeoftroy
10-26-09, 07:43 AM
I have a bungalow with insulation over my heated areas (in the ceiling) and insulation around my (in the walls and ceiling) bedroom and bath in the upper areas. My front porch is also under the roof but not insulated as well as my garage. Both non-insulated areas let air flow in that is not heated and it passes into my bedroom through standard interior doors since that air flow is under the roof in the attic.

Should I: 1. Insulate the porch and garage areas? If yes, do I use a vapor barrier? 2. Put exterior doors out to my attic?


Bud9051
10-26-09, 09:16 AM
Hi Mike and welcome to the forum. I don't have a real good picture of what you are dealing with so I'll answer in somewhat of a generic form.

First and foremost, air cannot leak in, unless it first leaks out somewhere else, thus airsealing entrances and exit leaks is very important.

Next, you need to define your thermal boundaries, those walls and ceilings where it will be cold on one side and warm on the other. This thermal boundary should act as an air seal and insulation layer. Your vapor barrier should be in contact with your air barrier and on the warm side of the insulation. Sheetrock is an air barrier, but moisture does migrate through it. It can become a vapor barrier, if painted with an oil base paint, but in both cases you would need to seal all penetrations and edges, electrical boxes, windows and doors.

As for your specific questions: 1. yes, insulate porch and garage areas that divide your living space from the cold and apply vapor barriers as described above. 2. The doors to the attic need to be insulated and well air sealed. If that attic space is open to a garage area, there are additional fire barrier requirements. Check your code department for specifics. If it is a standard door size, then an approved exterior door that would be used between a house and a garage should be ok. It just gets difficult finding something with an odd size or shape that meets codes.

If you would like to send some pictures I could try to be more specific. http://forum.doityourself.com/electrical-c-d-c/400914-how-put-pictures-your-post.html

Stay warm
Bud

PS here is some fun reading that may have a related area of concern: Welcome To Home Energy Magazine Online (http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/95/950309.html)