On Mar 5, 12:00*pm, "Existential Angst"
wrote:
"Lp1331 1p1331" wrote in message

...

I gotta go along with the others who say insulate the attic floor. From
what I have heard, foaming the rafters (underside of the roof) can cause
high humidity/condensation problems in the attic. I would use radiant
barrier roof decking and plenty of attic ventilation. You can reach a
point where slight gains in overall thermal efficiency can cause major
side effects that offest any savings exponentially. Larry

iirc, Silva on Ask TOH did a very inneresting ditty on insulation (esp.
spray insulations) very recently, and goodgawd, does it get complicated!
And it went by pretty fast, something you would def'ly want to take notes
on.

For example, the vapor barrier goes on different sides, depending on yer
climate.
In mixed climates, there are additional "breathable" barriers you can use..

Would be useful to catch that episode, don't know if the TOL has it.

Seems to me a double-layered roof, with a 2-4" air gap, with continuously
circulating air, and then the bottom layer super-insulated
(anything/everything) on the attic side would be a permanent solution.

But I've never heard of a double-layered roof, which seems simple enough to
do, just some extra plywood/2x4's.

I'm considering just living in a tent....
--
EA

Double layered roof is what you get when you put Spanish tiles on a
roof. The air can flow under the tiles. You get the same effect more
or less by putting foam insulation underneath the decking with an air
space between the foam and decking.

Jimmie