We have a modular Cape style house and the 2nd floor is unfinished.
Plenty of insulation between the first and second floor, but the roof framing members and collar ties are 2X6 and knee walls are 2X4.
How the heck can I attain recommended insulation values up there, especially between the tops of the knee walls and the collar ties?
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Replies
len.. draw a cross section of your cape and think about how you could max the insul..
if you have vented soffits.. use fiberglass insul as blocking and polyfoam ( egg-crate) air guides to direct air up the rafter bays to your attic..
install foam sheets ( i like 3" EPS ) on the back of the stud kneewall.. then blow the kneewall with denspak cellulose..
on the angled rafter sections .. you can install EPS foam across the rafters and furr it .. then blow dens-pak cells into the rafter bays.. in the flat portion of your attic ( above the collar ties ) you can blow 20" of cellulose
Mike Smith Rhode Island : Design / Build / Repair / Restore
Thanks Mike!
If you look at that cross section, the first floor ceiling is already insulated from one side of the house to the other, so I'm set there.
I guess I was really wondering if the angled section of the roof was considered as ceiling or wall.
If ceiling I just couldn't envision the R49 recommended with 2X6 framing.
To make matters all the more interesting, the ductwork for the central air runs the full length of the house behind the knee wall. The a/c with insulated duct worked very well last year so I'm not all that concerned with the ducting in an unconditioned area (there's no way this chubby guy is getting behind there to insulate the rafters!)
And wow, have you seen the price of the foam board lately!? The last I bought was maybe 5-6 years ago.
Thank goodness I don't really NEED that space up there.