In accordance with segment R806.3 of your 2006 Intercontinental Residential Code (IRC), “No less than a one-inch Place shall be offered among the insulation and the roof sheathing and at the location in the vent.” Such a vent Place may be established by installing one inch by 1 inch “sticks” in the upper corners of each and every rafter bay, accompanied by rigid cardboard, skinny plywood, OSB, fiberboard sheathing, or panels of rigid foam insulation.
I imagine that you might want to submit a sketch. I can't visualize what you are discussing out of your description. In order to put in an HRV in your attic, How come you must install a water-proof stucco roof more than some type of EPS box? Is just not your attic currently dry? Most attics have roofs.
Many thanks for the suggestions. We will never A/C the creating (Will probably be solar run). The wind is very constant, however it is a humid atmosphere, so humidity Regulate is absolutely on my brain.
Q. "If I execute the unvented roof as made and set 4 inches of polysio around the roof deck, am i able to then use open up-mobile foam in between the rafters?"
one. Take out the can lights and toss them away. Recessed can lights ought to under no circumstances be mounted within an insulated cathedral ceiling.
I think that Bill Rose is correct: these failures contain moisture that may be carried by going air. They are not diffusion failures. In the event the rafter bays genuinely are properly dense-packed -- a huge if -- the chance of air movement may be very low.
This short article was Very valuable, Thanks! I've one particular dilemma about creating a vented assembly by building an airtght technique with accuvents.
Set up shut-mobile spray foam towards the underside of the roof sheathing, and no other style of insulation. Ensure that the thickness of the spray foam is adequate to satisfy minimum amount code prerequisites. Take into account that open up-cell spray foam is dangerous in all local weather zones, and if open-mobile spray foam is mounted In this particular location in a chilly climate, the underside of the cured foam needs to be protected with gypsum drywall that's been painted with vapor-retarder paint. Vapor-retarder paint is ineffective whether it is sprayed instantly to the cured foam.
You say "You don't want an interior vapor barrier," but Additionally you state that "you need a very good air barrier on both sides of your fiberglass batts." The latter would turn out to be an interior vapor barrier not so?
Therefore the concern is: look at here now seal the stucco vents and increase the spray foam roof and Don't fret about condensation? There exists little reduced-hanging fruit Home Page inside our form of design, In particular on existing residences, And that's why consumers are remaining sucked in the spray foam roof scam.
You can skip the tape on the best layer of plywood to exact same some time and expense. That's most likely what I would do if I were being you. Having said that, there is not any harm in taping the seams of the top layer of plywood.
With regards to dense pack cellulose: unsure why dense pack could well be negated - I believe it properly suited.
Even though the GBA Web site already incorporates quite a few content articles on The subject, we go on to acquire Regular questions on The easiest way to insulate a cathedral ceiling.
Does it seem sensible to spray and Slash and cobble four inch closed mobile foam/board on underside of sheathing accompanied by fiberglass inside the bays and 1 inch of eps/iso beneath the rafter (to halt thermal bridging) just before finishing with drywall? Will I create a vapor sandwich and far better leave the ultimate EPS and take the thermal bridging?