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Upstairs Insulation between floor joists question . . Please help!!


CharlotteAnn's Avatar
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VA

04-30-09, 09:57 AM   #1  
Upstairs Insulation between floor joists question . . Please help!!

We have a cape cod house with an upstairs bedroom on one end. On the front and back section of the bedroom are knee walls. When I am in the knee wall, I can basically look at the insulation running from the kneewall floor going directly under the bedroom floor. So there is basically an open path from the knee wall straight through the floor to the opposite knee wall. (The floor to the upstairs bedroom is directly over the ceiling to the downstairs bedroom). Does this sound correct with there being a direct path from the front knee wall to the back knee wall?

 
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airman.1994's Avatar
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04-30-09, 06:36 PM   #2  
If I am understanding you right there is no insulation between the main floor and the 2nd floor. If that is right then there is no problem. Insulation is not needed between conditioned spaces.

 
GBR in WA's Avatar
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04-30-09, 09:20 PM   #3  
You want to seal any air gaps from under the ends of the living space to the attic. This is actually good from the government:

Welcome To Home Energy Magazine Online

Any questions? Be safe, G

 
Bud9051's Avatar
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05-01-09, 04:31 AM   #4  
Hi Charlotte. Capes are a challenge, I own one, GRRR. To comment on how much insulation you need we have to know where you are, just the climate area. If your kneewall is insulated and the roof rafters in those side attic spaces is not, then the floor area you are describing in the attic space needs insulation. But it also needs an air block where it heads under the kneewall, under the bedroom floor, over to a block at the other kneewall, and then to insulation in that other attic space.

Some questions: Do you have vented soffits and gable or ridge vents? Are those sloped ceilings in the bedroom insulated and can air pass above the insulation? Is the access opening to those side attics air sealed and insulated? Is there a plywood floor in those small attic spaces or are you looking at exposed insulation and what type of insulation?

That will get you started.
Bud

 
CharlotteAnn's Avatar
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05-01-09, 06:50 AM   #5  
Thanks . . . here are some answers to the questions . .

Airman.1994 question: Yes, there IS insulation (batt) that between the main floor and the 2nd floor.
GBR in WA, thanks for the info from Hone Energy Magazine!! Looks just like what I'm talking about. I'll study it . . .
Bud9051: I understand your GRRR . . . if I'd known when we built the house what I know now, but oh well . . . I live in the southeast (VA). Answers to your questions:

Kneewall floors are insulated, but I can look at the floor insulation in the kneewall and see it running directly under the floor of the upstair bedroom straight through to the opposite kneewall. Roof rafters above the upstairs bedroom ceiling have batt insulation. In the front of the home the batt insulation is pack tight up to the actual roof sheathing. We do have in the front of the house a few, just four or five soffitt vents and we do have a ridge vent on the top of the roof, and a gable vent in the attic area over the bedroom, but the way the insulation is packed in the front of the house, no air way. But, no wet or moldy ceilings in the 20 years we've lived there, at least not in the front of the home (that gets the sun). Now, in the back of the house (facing North) we did have moisture issues from insulation blocking the airway, which we did fix in the bedroom area but not in the cathedral ceiling area on the other end of the house. I know this is confusing. Access openings to side attics do have some insulation on the doors (that hard pink board stuff, maybe 1/2 in thickness, and weather stripping. the Plywood floor in the small attic space (have you been to my house? you sure know it well has insulation under it. I'm exhausted.

 
Bud9051's Avatar
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05-01-09, 07:30 AM   #6  
Sounds like you are in pretty good shape. Watch for moisture problems and vent as needed. Find a way to block any air flow from the small attic spaces to the gap under the bedroom floor. A couple of options are blown in cellulose insulation, but it must be solid, not just over the top of fiberglass. Fiberglass does not block air flow. The other way is to install blocking, either wood or rigid foam, cut and fit between each joist. I have had to cut and remove some of the plywood to gain access, but it is important and not really that hard to do. At least when you are younger and thinner than I currently am.

VA can get cold and energy costs can go higher, so don't skimp on the details, they pay off. The sloped areas generally limit adding any more insulation, so consider if the time comes, adding a layer of rigid on the inside over the sheetrock and then adding another layer of sheetrock. Easier than tearing out and doing totally over.

"Beauty and the Beast Upstairs" is a good article, in english, and there are many on this board available to help, so good luck.

Bud

 
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