Knee wall Attic insulation

Old 02-16-03, 07:19 AM
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Question Knee wall Attic insulation

I have an A frame home. On the second floor the knee wall creates an attic space triangle. Roof, ceiling of the first floor, and the knee wall. It is large enough to crawl around in. A squirrel got into it and destroyed the existing insulation. I am now faced with repairing/replacing it. The floor in the crawl space has plywood on it with insulation between the studs below. The Knee wall had R-13 unfaced batts. The roof had R-19 faced batts (24 on center). Seeing that this is a cold space, I didnt think that the roof trusses should be insulated. The roof overhang Soffit does have a continuous vent and it appears that this roof insulation partially blocks any air movement up to the ceiling attic, although there are tubes from the vent to the knee attic space. The insulation on the roof rafters blocks any air movement to the upper attic. What is the proper installation?
Old 02-18-03, 06:21 PM
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Most energy conscious builders in our area have stopped insulating the floor joists and then insulating the knee wall studs. The details to make sure the building envelop is adequately insulated and no voids/breaks in it can be tricky. Most situations as this I insulate the rafters and ommit the wall/floor insulation. If your knee walls and floor system is insulated then having the rafters as well is overkill, but it shouldn't be hurting anything, assuming you do have them vented well from eave to roof ridge. There are a lot of folks in our area that are becoming strong advocates of doing non-vented cathedral ceilings, but I won't get into that right now b/c that is not my area of expertise.
Old 02-24-03, 08:32 AM
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word of advice....

A few words of advice regarding fiberglass insulation that I don't believe is stressed enough...

1. cover yourself adequately: long sleeves, long pants, gloves, goggles. I used a one piece, disposable suite.

2. a good respirator-not a mask especially if this is a tight area and you'll be pulling on old insulation

3. don't carry old insulation through house or bag it carefully.

4. don't wash any clothes used while working with insulation with any other clothes.

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