关于凤凰的酷屋顶故障的文章？
这将是一个超级疏远的问题，对大多数人阅读这一点，但希望不是至少一个人。
I’m trying to find an article describing the failure of the roofs of some upscale homes in Phoenix due to their use of either white roofs or radiant barriers but without handling ventilation properly. I read it within the past year but don’t know if it was written recently. I’m asking here as a last-ditch effort if only because y’all have a much higher likelihood of reading an article like this than most.
好的，更多细节我能记得。建筑师用绿色建筑原则建立了整个社区，但经过很短的时间（6个月至一年），新房主在天花板上抱怨明显的凝结。当他们进一步调查时，他们发现屋顶甲板经常用显着的腐烂和模具形成湿润。给出的解释是，白色屋顶反射如此大量的热量，即甲板的顶部实际上比环境空气更冷却，因此在下侧聚集的冷凝聚集。这导致了大规模的问题，也许是因为通风完全错了？我的记忆力在故事的这一部分开始失败，这是我想要记住的部分。
Basically, I want to re-read what precisely went wrong and how they ultimately fixed it.
Anybody remember reading such an article?
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答复
Kurt,
问：“任何人都记得阅读这样的文章吗？”
A. I have written several articles in which that case was discussed. One such article was titled"Night Sky Radiation."
To read about the failures related to white roofing, scroll down to the section with the heading, "Radiation to space happens during the day, too."
谢谢，马丁！棒极了。
Okay, I want to make sure that I understand what happened and what the ramifications are. Don't assume I understand this at all, in the following, I'm very much still learning.
With the heavily reflective white roof radiating so much heat on a clear day, the OSB sheathing ended up being a good 8 degrees colder than the ambient temperature both inside and out. Say the ambient outside temp was 40F and the dew point was 34F. With the OSB sitting at 32F, we're almost guaranteed condensation.
但由于屋顶的顶部可能是密封良好的（平屋顶和全部），因此任何蒸汽都不可能从外部到达OSB以能够冷凝。让我们留下了内部空气。
在这种情况下，玻璃纤维壁靠在OSB的下侧。我不确定空气的温度在那一点上，但由于它处理了室内空气（最终），所以甚至不仅仅是40f室外环境。并且由于玻璃纤维甚至没有稍微蒸汽不可渗透，因此靠近OSB的下侧有大量的温暖潮湿的空气......因此冷凝，没有真正的方式将其擦掉。
The solution those builders went with was to install rigid foam on the outside. On that same 40F day, the outer-most part of the foam would be lowered to 32F (since still painted white, likely) but it's still impermeable and so the moisture has nowhere to go. Meanwhile, the foam has insulated the OSB and so it's nowhere near 32F or even 40F. Problem solved.
我想更多地探索这个想法。如果，代替将刚性泡沫放在外面，建筑们在内部喷洒闭孔泡沫？现在，OSB在两侧都是不可渗透的，即使TEMP低于露点，水分也可以凝结在外部密封表面上。看似也可以解决这个问题？
如果玻璃纤维BATT和OSB的下侧有通风通道怎么办？现在我们在OSB下有了移动（？）空气。这足以让露珠上方的OSB温暖吗？或者失败，空气足以干燥OSB？
I've read a few documents from the Dept of Energy and BSC about unvented attics that reference using permeable insulation (like blown cellulose) up against the roof deck but ONLY in hot-dry places like Phoenix or Las Vegas. Those don't make any reference to roof color, though. Presumably the assumption with that recommendation is that the roof would be a much darker color? Or... are they saying it's okay because those are sloped roofs and maybe that changes the equation? It certainly seems like that recommendation is describing a use-case just like the known roof failures in Phoenix.
This source reports sheathing being an average of 1C cooler than ambient, which doesn't have much impact.
http://rdh.com/wp-content/uploads/2015/03/The-Problem-with-Ventilated-Attics-RCI-March-2015-Nov-5-2014-For-Printing.pdf
Most wetting comes from air movement (even interior to sheathing and back to interior) - so an interior side air barrier is critical to limiting the amount of moisture.
>玻璃纤维甚至没有一点点蒸汽不可渗透
But painted drywall (or Membrain) can be.
Kurt,
问：“如果，而不是将刚性泡沫放在外面，而不是将刚性泡沫放在内部的封闭电池泡沫？现在，OSB在两侧都是不可渗透的，即使温度低于露点，水分也可以凝结在外部密封表面。看似也可以解决这个问题？“
答：是的。That approach is used frequently. For more information on that approach, see these two articles:
"How to Build an Insulated Cathedral Ceiling"
“绝缘低矮的住宅屋顶”
Q. "What if there was a ventilation channel between the fiberglass batts and the underside of the OSB? Now we'd have moving(?) air under the OSB."
答：是的。同样，这种方法很常见，因为你知道你是否阅读这两个文章：
"How to Build an Insulated Cathedral Ceiling"
“所有关于阁楼通风”
Note, however, that low-slope roofs are different from steep roofs -- if you want to vent a low-slope roof, you need an entirely different approach from the approach used for a steep roof. Again, this article explains what you need to know:
“绝缘低矮的住宅屋顶”