Thorsten Chlupp is in a very Considerably more difficult weather and he is apparently accomplishing fine with easy free fill over the attic flooring....naturally he is making use of "enough" quantities (cellulose galore)and he has baffles near the soffit.
Thank you, Martin and Stephen. The good thing is we've been inside a condition in which we are able to pause and reconsider, as the new felt continues to be positioned, but they haven't started off setting up shingles nevertheless. I'll talk about your situation Together with the contractor all over again. I may be able to get him to reconsider.
Q. "You say 'You don't want an interior vapor barrier,' but In addition, you state that 'You will need a superior air barrier on either side of your fiberglass batts.' The latter would turn into an inside vapor barrier not so?"
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If you prefer, you can Identify your ventilation channels on top of the roof sheathing as an alternative to under the roof sheathing. If you decide to do that, Ensure that any roofing underlayment that you install above the roof sheathing is vapor-permeable — such as, #fifteen asphalt felt, VaproShield SlopeShield, or Solitex Mento — Which your neighborhood building department accepts this method of roof venting.
sips are excellent but in the coldest of climates they've encountered challenges. google trouble programs in alaska - evidently a group of properties there have been constructed but not ample attention to element for the plumbing and roof vents were taken into consideration (Certainly air restricted foamed in penetrations), mated panel seams and fastener punctures caused the best amount osb to rot. Evidently The full roofs needed substitution.
The roof seems to possess a layer of asphalt shingles above the sheathing by using a tin roof around that. The soffits are shut off. The house is way from the overwhelmed path and It really is hard to get any contractors on the market to operate, not to mention supply bids so I'm essentially alone.
Like most mansard roofs, your roof is unvented. Your mansard roof has distinct sections -- the steep sections in the perimeter, plus the lower-slope portion in the center. All of these sections need to be insulated in a similar way, mainly because all of these roof assemblies are unvented.
You happen to be in climate zone 5. I spelled out the minimal R-values with the strategy that you are taking in one of several paragraphs above, through which I wrote, "In keeping with .
Your caveat is appropriate and conservative. With the vast majority of builders, on the other hand, the code prerequisites will maintain roofs freed from difficulties.
The R price of a knockout post your Reduce'n'cobbled foam + exterior foam should be at least forty% of the middle-cavity R worth for dew issue Management with the foam/fiber boundary in zone five. If It really is developing somewhat shy of that right before incorporating the outside foam it isn't a giant deal while in the temporary, however, if it is going to be 5-ten years right before re-roofing to lift the foam-R to previously mentioned forty% of the full It really is worthy of working with vapor barrier latex primer around the gypsum board, or a smart vapor retarder involving the gypsum board & fiberglass.
As Invoice Rose notes, air tightness on the assembly, each inside of and out, is of crucial great importance - we have to stop the air move. Thus I'd propose an assembly that makes use of resources intended to supply air tightness though also maximizing the drying likely of the roof assembly. The detail illustration I've attached demonstrates this kind of an tactic. Solitex Mento one thousand membrane is used on the outside in the insulation - a vapor open up, nonetheless water and air-restricted substance - with vented cavity above - making it possible for for max drying out and avoiding any wind/air penetration of the insulation.
I have by now insulated the steep sides of my unvented mansard roof with 6" fiberglass (And that i experienced it inspected), does one endorse I rip that out and use spray or board foam? I have gotten conflicting details on irrespective of whether to deal with it for a wall or possibly a roof.
A vented cathedral ceiling only makes sense Should the geometry of your roof is simple. You need a straight shot from the soffits into the ridge. That’s comparatively quick with a gable roof with none dormers or skylights, but Should the geometry within your roof is sophisticated — with options like hips, valleys, and dormers — it’s impossible to assure air flow through your whole rafter bays.