Have a question regarding how to handle insulating some spaces in my house. I’m looking at getting bids for blowing cells OR doing it myself, either way I want to educate myself a little on this particular aspect of the project.
In the pic I attached, I’m concerned about the sloped section that I’ve shaded in. There is an area like this at each corner of the house, 3 of them are above a closet in each bedroom, and one is above the staircase. They are 2×6 construction with the roof on the top and the plaster ceiling of the closet/staircase on the bottom. Since one side is roof facing and the other indoor facing, I need to allow an air space for ventilation.
This rafter bay does open into the attic where the slope intersects the attic floor, then the bays are open up to the ridge. Question is, since I can’t access the space above the living space, how do blow cells in there and leave an air space?
My thoughts so far are to just slip some 1″ foam board down there the width of the rafter spacing to at least make an effort to insulate it.
Thanks, PJ
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densepacked cellulose or BIBBs
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Well, densepacking is not the answer I was expecting, but there seems to be agreement... No one said they didn't understand my drawing, but I'm wondering if maybe it wasn't good enough. I guess I'm just confused as to why it's ok to sell up a space that has roofing on one side of it - don't I need venting to prevent moisture buildup in the cells?
These particular rafter bays do open into the attic space, which is ridge vented. There are no eave vents in these short slopes since the actual eaves are quite small and their location relative to the ground didn't make it easy for me to add them - though I did add vinyl eave venting to the main eaves of the house before I baffled and insulated the rafters on the main part of the roof.
Roofing is asphalt shingle.
Thanks guys. PJ
The theory and thinking behind this is that you eliminate a dewpoint where condensation can occour when you do one or both of the following;Totally instal;l a perfect VB to keep all airborne moisture from reaching cold space where it can condense. This means sealing all penetrations.Use an insulation that precludes movement of said moisture containing air through it via convection currents, and use it thick e3nough to provide enough r-value to isolate existing moist air from cold spots/dew points.The best insulation is a polyurethyne foam sprayed in place, but it is expensive and more so when finish cielings and wall surfaces are already in place. Thus the practical cellulose recommendation.personally, I hate cellulose, having had to remodel far too many homes with cells. It can really make a mess if you ever have to open up a wall later.
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OK, I thought that spray foam was the only really reliable way to "completely insulate" an airspace with no worry about condensation forming - I guess really densely packed cellulose install can do the same. The good thing is doing a dense pack in this particular space, compared to an enclosed wall space, should be much easier.
Thanks all, PJ
Is the roof vented now?
Are there openings at the facia area in these 3 areas you're concerned about?
What kind of roof material?
I'd dense pack with cells no matter what the answers are, but others mileage may vary.
Joe H
What they said...really good stuff there.
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