Insulation/venting ceiling w/flat roof
chrisjohns
| Posted in General Discussion on
It’s time to insulate and finish the ceiling under a flat roof that I re-built (weekend DIY’er).
The roofing is Pacific Polymer Elasto-Deck 5000 x2, a system not unlike Seal-o-Flex.
The ceiling is 9’x9′, the ceiling joists are 2×10 on 16″ centers.
The space would be used for dining area. The humidity is generally very high inside and out due to over water location. Temperatures outside range from 40s to 80s. No ac. Lots of windows and the room is open to the rest of the 1st floor and second. I plan to put 5/8″ sheetrock on the ceiling.
Thoughts on insulation? Vapor barrier? Kraft faced. Plastic faced? Unfaced? Venting above insulation?
I’d appreciate any and all thoughts.
Replies
In order of preference
sprayed foam
denspacked cellulose
BIBBs
FG batts covered below with Thermax before SR
Insulate well and use VB and you need no vent, especially with open to rest of house.
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thanks,
thoughts on using the fiberglass insulation which is encapsulated in plastic, with integral plastic flanges for stapling?
IMO, that plastic wrap is a marketing ploy but does make it easier to install for a DIY. Stilll batts, good to use a foil faced polyisoanurate board to the interior siode of the framing before SR. Tape the joints in #### and you have your VB while adding considerable R-value
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I'm happy with R i get from 9-1/2" of fiberglass, but, would use the polyiso if i could. i have build up issues such that i can only have 5/8 sr.
i've found tape (duct) that came apart over time when i demo'ed some of my project. probably specific to the wet environs.
the plastic bagged stuff has fine holes in it and yes it is very easy for the DIY'er. i've only set one staple in my fingers applying it.
i wonder what is a good sheet product to use with unfaced? i have a surplus roll of foil faced reinforced "paper" (like the stuff you see on the inside surface of auditoriums). Maybe that is a good use for it.
better tape?