Insulated cathedral ceilings are a comparatively current phenomenon. The craze for insulated cathedral ceilings (and great rooms) genuinely took off during the 1970s and eighties, when illustrations started popping up like mushrooms after a warm rain.
The 1st vent baffles to hit the marketplace — the classic Proper-Vent in the nineteen seventies and ’80s — have been inexpensive, flimsy things crafted from slim polystyrene. Polystyrene baffles have quite a few disadvantages: becoming slender and versatile, they can’t resist the pressures from dense-packed cellulose or blown-in fiberglass; they don’t ventilate all the width with the rafter bay; and as ordinarily set up, they permit air to leak out the top of your insulated assembly.
Ought to I exploit airtight baffles or not, I do not see a means to have moisture escaping in a assembly with airtight baffles, fiberglass and xps on the inside, it doesn't matter what the dew position will be within this assembly and possibly create condensation that cannot evaporate with no air flow.
Thanks Martin - Now I see why my initial approach for a SIPS envelope was so elegantly easy. It looks like min R-10 sprayed under the roof sheathing after which a complete-fill with the bays with batt / fluffy, plus a vapor sealed drywall lid can get me the 'warm' (unvented) roof system the SIPS was from your get go.
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JB- I actually must put up sketches as Ken did. It would in all probability save some difficulties. For me this was harking again into the compact roof string.
The roof appears to possess a layer of asphalt shingles in excess of the sheathing that has a tin roof in excess of that. The soffits are closed off. Your house is way off the overwhelmed route and It is really challenging to get any contractors around to operate, let alone deliver bids so I'm pretty much by myself.
Am i able to get some a lot more commentary over the "whole roof" of Ice & H2o Protect? I do think this experienced very little to complete Using the failure. The explanation why I inquire is I have a similar "whole roof" structure coming up, Nonetheless, the rafter bays are all straight operates with soffit vents, continual vent baffles (1/2" plywood) and continuous ridge vent. Dense pack cellulose, two" XPS under 2x10's, air limited drywall (XPS could possibly be sealed up too).
Should your climate is not really far too significant it's probably ok to own just the R-10 foam around the structural steel, Though there's some chance the metal could sweat in chilly temperature. I am assuming In addition, you meant to insulate the 2x12 joist bays to get your complete R-value to an affordable degree.
With my house the middle portion (20ft) is vaulted, a 3x12 slope and has eight recessed lights during. I've had leaks in many locations Within this section of your house, the leaks transpire While using the thaw and refreezing. It acquired The purpose previous calendar year where I had to shovel the complete roof soon after Every snow slide.
Component D: Both notch the handled 2x4 spacers for fitting 1x4's horizontally across them in an effort to ...Aspect E: Put in metal roof in excess of this.
Rafters are 2x4, twelve/12 slope, and also the roof is intricate with intersecting ridge traces, valleys and dormers. (Your home originally experienced a cedar roof. The deck is the normal spaced fir planks.) On account of the development, there is nearly no potential for receiving satisfactory air intake by using soffit vents. (On top of the layout concerns, you'll find challenges simply because the many Areas between rafters exactly where they satisfy the best plate have been bricked in, apparently at time of construction). Good regular stream-by means of underdeck roof air flow will probably be complicated. Once we to start with look what i found looked into this job, the developing inspector requested us to however use vent channels (inexpensive polystrene was Alright) to seize whatsoever ventilation we could.
If you are creating a cathedral ceiling, the largest air-barrier blunder is to set up tongue-and-groove boards as your complete ceiling without having very first putting in taped gypsum drywall. A board ceiling is notoriously leaky, and this type of ceiling is often affiliated with roof sheathing rot.
Like Doug's style and design, the focus is on creating a significant perm layer for drying to the exterior, that can however permit venting though blocking wind washing from the fluffy things.