If you would like use just one form of insulation in unvented rafter bays, you happen to be restricted to spray polyurethane foam. Yet another probability, naturally, is to make your roof with structural insulated panels (SIPs).
Okay, I had been figuring that the entire in the rigid foam + cellulose needed to be a certain R-value together and were thinking of working with significantly less rigid foam. I've been reading about various kinds of cellulose. Since I am installing from over would some thing like stabilized cellulose work as it has a bit h2o extra?
I purchased a catastrophe of the property that was partially remodeled, it's in Zone 16 (a California designation similar to IRC zones). It's a six/twelve vaulted ceiling in excess of the residing/kitchen area. The roof is held up by two very long beams that run 4 ft out parallel on the ridge , So there is no straight air route a just how approximately the peak ridge beam.
Regarding dense pack cellulose: undecided why dense pack could well be negated - I believe it correctly suited.
Many thanks for your input. I see a stop by having a structural engineer and 35 square of polyiso in my around future.
The air leakage that Dana pointed out would keep the roof dry, but would undermine its thermal efficiency.
I made use of to operate as being a roofer, and roofs which are solely protected with Ice & Water Protect make me anxious. I see this sort of structure as lazy and likely problematic.
The bottom line is that, so long as your roof sheathing is relatively dry in the event the roof is shut in, you ought to check it out be good, even without outward drying. I might go ahead an put in the peel-and-stick membrane inside the valleys and at the eaves without worrying.
It is really undoubtedly not blog restricted to an R eighty Passive Dwelling roof. Consider out the parallel chord trusses and slender it up.
If you're taking into consideration going to several destinations or perhaps interested in different areas of the country, you ought to evaluate numerous cities.
I have a series of queries that integrate many of the topics that you've covered in these content, but I'm attempting to apply them in the retrofit situation. We're engaged on upgrading the Vitality performance, together with added/updating insulation, for our Virtually 100 12 months aged 2-1/two Tale balloon body house (stucco about lathe exterior).
Doug... For a few rationale I did't see your write-up #17. Appears like two of us at the least Feel there may be a surprisingly easy reasonably priced Option.
I'm which include a photo of the solution: spray foam held down from the best fringe of the rafters to ensure air could be drawn up from soffit you could check here vents to gable vents in the truncated attic cavity.
Like Doug's structure, the focus is on creating a higher perm layer for drying to the outside, that can still make it possible for venting while blocking wind washing while in the fluffy things.