Per 2010 IRC Code, Polyurethane spray foam insulation may be used in an UNVENTED roof per below: SECTION R806 ROOF VENTILATION R806.1 Ventilation required. Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Ventilation openings shall have a least dimension of 1/16 inch (1.6 mm) minimum and 1/4 inch (6.4 mm) maximum. Ventilation openings having a dimension greater than 1/4 inch (6.4 mm) shall be provided with corrosion-resistant wire cloth screening, hardware cloth, or similar material with openings having a minimum dimension of 1/16 inch (1.6 mm) minimum and 1/4 inch (6.4 mm) maximum. Openings in roof framing members shall conform to the requirements of Section R802.7. R806.2 Minimum area. The total net free ventilating area shall not be less than 1/150 of the area of the space ventilated except that reduction of the total area to 1/300 is permitted provided that at least 50 percent and not more than 80 percent of the required ventilating area is provided by ventilators located in the upper portion of the space to be ventilated at least 3 feet (914 mm) above the eave or cornice vents with the balance of the required ventilation provided by eave or cornice vents. As an alternative, the net free cross-ventilation area may be reduced to 1/300 when a Class I or II vapor barrier is installed on the warm-in-winter side of the ceiling. R806.3 Vent and insulation clearance. Where eave or cornice vents are installed, insulation shall not block the free flow of air. A minimum of a 1-inch (25 mm) space shall be provided between the insulation and the roof sheathing and at the location of the vent. R806.4 Unvented attic assemblies. Unvented attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) shall be permitted if all the following conditions are met: The unvented attic space is completely contained within the building thermal envelope. No interior vapor retarders (Class I or II) are installed on the ceiling side (attic floor) of the unvented attic assembly. Where wood shingles or shakes are used, a minimum 1/4 inch (6 mm) vented air space separates the shingles or shakes and the roofing underlayment above the structural sheathing. In climate zones 5 and 6 any air-impermeable (eg.- spray foam) insulation shall be a Class III vapor retarder, or shall have a vapor retarder coating or covering in direct contact with the underside of the insulation. Either Items 5.1, 5.2 or 5.3 shall be met, depending on the air permeability of the insulation directly under the structural roof sheathing. 5.1. Air-impermeable (eg. spray foam) insulation only. Insulation shall be applied in direct contact with the underside of the structural roof sheathing. 5.2. Air-permeable (eg. fiberglass or cellulose) insulation only. In addition to the air-permeable insulation installed directly below the structural sheathing, rigid board sheet insulation shall be installed directly above the structural roof sheathing as specified in Table R806.4 for condensation control. 5.3. Air-impermeable and air-permeable insulation. The air-impermeable (eg. spray foam) insulation shall be applied in direct contact with the underside of the structural roof sheathing as specified in Table R806.4 for condensation control. The air-permeable (eg. fiberglass or cellulose) insulation shall be installed directly under the air-impermeable (eg. spray foam) insulation. TABLE 806.4 INSULATION FOR CONDENSATION CONTROL CLIMATE ZONE MINIMUM RIGID BOARD OR AIR-IMPERMEABLE INSULATION R-VALUEa 4 R-15 5 R-20 6 R-25

I realize this is silly and not even close to relevant. But... From you... "I just measured the temperature of a heatsink in an open trim can at 140° and if there were nowhere for that heat to go, the bulb would fail sooner than later." and also from you, "Failure is failure, and a condition of continually too hot is supposed to be even harder on them regardless of what kind of an exotic name they give their test." and finally one more, "When you have 120° degree summer heat pounding down on a cathedral ceiling roof, and the heat sink is 4" underneath that with insulation on the sides, it keeps the heat from escaping the bulb and it WILL heat up to the failure point." Now from the report that you provided, "The lamps were operated continuously at an ambient temperature of 45°C" and "While none of the LED lamps exhibited catastrophic failure—and all of the benchmarks did—the early degradation of performance is concerning." If you examine the actual study further you find that only two of the 15 samples were below purported luminosity after the test. Remember NONE FAILED. If someone maybe said earlier in the thread, "The concern with operating LEDs above their optimal temperature is usually luminosity degredation not failure. Wait, someone said that earlier you say? Could it have been me? Surely not, because you shot back with, "Put the lamp in a ceiling-mounted fully enclosed fixture and set the timer for when failure will occur." To put this in perspective, Assuming you operated the light for four hours per day in ambient temperatures in excess of 113 degrees, and 8 hours on the weekend at those temperatures, and the temperatures remained that high for 33% of the year, AND you chose one of the 13% of bulbs that don't last long, you will only get 9.6 years before your lights are noticeably dimmer (remember not failed, just dimmer). Of course, if you picked one of the others that were predicted to fail you can extend that another 9 years or so. While if you got lucky in your bulb selection, you are good for the long haul. I never argued that LEDs were good, I stated that they were better than any other alternate bulb. And they are... Now, please take your time, come up with some more evidence that completely contradicts everything in your previous points while you deftly switch your stance (since you have managed to go from led bulbs are bad because they fail, to led bulbs are bad because they degrade, to led bulbs are the best but can lights are bad in this application).

I think the back of the house could use a little dimension...it all seems a little flat right now and not sure how that will look from the exterior? I don’t know if there’s any specific nice view out the back that you want to preserve/enhance, but having 1-2 bump outs might be nice. They could also get you some new windows in different directions, bringing in some different light. For example, you could bump out your living room so it’s not in a flat plane with the rest of the house. If your living room currently has a western exposure (I forget what the orientation is), you could then get north and south exposure by adding windows along the sides of the bump out. You could maybe even add some doors to the outside on the side of the bump out so you don’t have to squeeze by the dining table to access the sliding door - that’s how my house is currently and it is sort of annoying sometimes. I’m not an architect, so I don’t know the term for it, but adding a little dimension along the back might be good, unless you’re going for a super formal symmetrical aesthetic, which I don’t think you are.

We had a similar problem with our roof and high ceiling. We had to hire a roofer to lift the ridge cap on the exterior roof and open it up. He found that the roofers had laid material over the peak without venting it. So they had to open up the material, install venting and replace the roof cap. When they did that the dripping and leaking finally stopped. So you will have to hire a roofer to get up on the roof and check from up there. It solved all our problems I hope it solves yours. Good luck and best wishes.