You describe your proposed air barrier as "taped felt." I don't Assume asphalt felt might be effectively taped, and I don't are convinced asphalt felt can make a very good air barrier.
Chuck- Google "reclaimed foam." There are a variety of sellers of reclaimed foam in MA. You are going to preserve a bundle and assist the World to boot.
You wrote, "the rafters are still uncovered," but I am not sure Anything you indicate by that. Do you have kraft-faced batts between the rafters, Using the kraft struggling with even now seen?
You are proposing a vented roof assembly. For just a vented roof assembly, the code would not demand that any foam insulation be put in direct contact with your roof sheathing -- on the contrary.
I have built log properties within the Yukon Territory in northern Canada for 30 years. Most log properties have cathedral ceilings. Almost all of the roofs we have built are as follows (from The underside up): log purloins, nominal 2" (2x6) t&g decking, 6mil poly, 1 one/2" extruded polystyrene foam, 2x10 rafters on 24" facilities, seven" fiberglass, 2x4 strapping, seven/sixteen OSB, underlayment (fifteen lb paper, 30lb felt, or now we'd even use ice and h2o protect). There could well be about an inch of air Room under the strapping for the two vertical and horizontal air move. All roofs are vented with strip vents with the eaves and vents while in the soffit (2x6 t&g) at the height at the two ends. I'd disagree that venting is not essential for those who prevent the airflow on the warm aspect, for two good reasons. Initial it's very difficult to stop all airflow, Specifically with typical common methods (ie chimney and plumbing vent penetrations throughout the roof) We have now many strategies produced over the years to seal the vb within the eaves and gables, but there remain nail penetrations from the vb. Overall I feel we had really tight seals but a single could never say airtight.
Your intend to use 2-inch-thick EPS as your ventilation baffle will perform. The EPS is somewhat vapor-permeable, so it will permit a small amount of outward drying. (In almost any scenario, in the event you Develop a reasonably airtight ceiling, there will not be any dampness Within this assembly that should escape.)
The R worth of your Slice'n'cobbled foam + exterior foam needs to be at the least 40% of the middle-cavity R worth her explanation for dew stage Command in the foam/fiber boundary in zone 5. If It truly is coming up a tad shy of that in advance of incorporating the outside foam it's actually not a huge deal in the short term, but when it's going to be five-ten years right before re-roofing to boost the foam-R to over forty% of the overall It is really well worth using vapor barrier latex primer within the gypsum board, or a smart vapor retarder amongst the gypsum board & fiberglass.
To comply with the code -- also to undertake a setting up program that is definitely considerably less dangerous -- you should both involve ventilation channels or you need to put in a layer of spray foam over the underside from the roof sheathing, adhering to the recommendations stated in the post on this website page.
It's really a code violation to set up an air-permeable insulation like fiberglass batts in between unvented rafters. It is also a bad notion, due to the fact moisture can accumulate on the roof sheathing if you are trying this technique, and you may end up with sheathing rot.
Another concern that Click Here comes up in that click this link scenario is whether or not that could encourage condensation over the underside of the 1" XPS when it is actually chilly sufficient outdoors because the underside from the XPS could be down below the dew issue? Q-three: What to do whenever we re-roof.
Many thanks for your confirmation and information. Considering the fact that all the things is dry this time of yr and the home was recently tented for termites, I'll insulate because of the beam and seal up the apparent air entryways. The moment I'm able to see inside I think I'll have a far better idea just how much moisture has become in there over time.
Can I get some additional commentary about the "full roof" of Ice & H2o Defend? I feel this had hardly any to accomplish While using the failure. The reason why I check with is I've an identical "complete roof" design coming up, Even so, the rafter bays are all straight runs with soffit vents, continual vent baffles (1/two" plywood) and continuous ridge vent. Dense pack cellulose, 2" XPS below 2x10's, air restricted drywall (XPS could possibly be sealed up too).
My feeling would be that the dew position profile would wind up during the XPS foam board, that's why a VB must be put on first deck. So as of assembly:
Owning put in all my daily life guiding a desk working on this can be a little bit of a crack. The roof will likely be carried out in Possibly four sections so may perhaps check out rigid foam and spray foam to match what performs. Rigid foam is tiresome but negligible sticky residue. Thanks.