Hot roof underlayment: TigerPaw?
I will have an unvented roof assembly. I was looking for an underlayment for my roof deck. I noticed that sharkskin and others aren’t going to work, as they are very low perm.
It looks to me like TigerPaw would work, or would you just throw down a 30# felt, or some other product ?
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Sleaton,
1.我不确定是否我同意你的看法at TigerPaw underlayment can be used with unvented roof assemblies. TheTigerpaw安装说明注意，“必须在屋顶设计和安装中进行规定，以提供适当的通风，以避免高湿度，冷凝和模具生长问题。”
此声明有点含糊，因此您可能希望与GAF代表与GAF代表讨论是否在未辩护的屋顶上使用Tigerpaw违反保修要求。
2.为什么界定问题的蒸汽渗透性？大多数类型的屋顶都不允许向外干燥。你能告诉我们你将安装什么样的屋顶？
This will just be Owens Corning Oakridge over an unvented roof. I verified with Owens that they have modified their warranties of late and do cover unvented roof assemblies. The roof will be sprayed with 9in of open cell underneath and covering the rafters. I have read on numerous underlayment documentation and other places on this site, not to use sharkskin and to be very picky about what underlayment to put over the osb under the shingles on an unvented assembly. I am starting to lean towards 30# felt. On the GAF site it claims "Help reduce damaging moisture that can become trapped on your roof deck, Helps remove nearly twice as much damaging moisture from your roof deck as the leading synthetic non-breathable underlayment" on both TigerPaw and Deck Armor underlayment. I will have whole house dehumidification (Austin Area), but even with that, I know there is much debate about open cell and OSB rotting.
That was pretty much my concern.
Sleaton,
You are right to be concerned about moisture accumulation in your roof sheathing, but you are mistaken if you think that the roof sheathing can dry to the exterior -- no matter what type of roofing underlayment you specify.
帮助屋顶护套到外部的唯一方法是建立通风通道，坐落在屋顶护套上方的脊。
I wasn't sure what "Owens Corning Oakridge" means, so I googled it. I guess you are talking about asphalt shingles. They don't allow any drying to the exterior.
If going with fiber insulation and an unvented roof, the shingle underlayment isn't going to make the difference. But there is reason to believe that a replacing foot of roof decking at both sides of the ridge with exterior grade fiberglass faced gypsum board covered by a mesh type ridge vent, and using dense packed cellulose as the insulation can have a substantial benefit. The highly permeable gypsum board at the ridge with the mesh vent above it is referred to as a "diffusion vent". An alternative is to See:
https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/unvented-roofs-asphalt-shingles-cold-hothumid.pdf
福利的最短摘要在表7，第56页（P69在PDF分页中），但阅读整个东西（乏味可能是......）
表7没有告诉整个故事 - 截面（屋顶＃4），最低的ASHRAE 160故障时间是玻璃纤维绝缘在顶部通风的配置中，但在事实后解剖组件比纤维素在纤维素上显示更大的湿度损伤绝缘海湾。扩散的通风纤维素托架的水分含量高于所需水平，但比未辨别的致密填充纤维素更快地干燥。
在温暖的潮湿气氛中，通过覆盖脊通孔的任一侧，覆盖空气密封衬垫的漫射通风口使得甚至没有内侧蒸气延迟器的玻璃纤维绝缘，覆盖它的覆盖物。从P.65开始，参见图95,96,97和98（PDF中的第78页）和表12，P.92（P.105在PDF中）
Asphalt shingle systems dry to the exterior at some low rate (say .1 to .65 perms depending - and note that dry cup measurement is the wrong test for this). That's not much, but I haven't seen evidence that this isn't significant when the wetting rate is less than this (ie, no air flow and low perms to the interior - possible with open cell + a vapor barrier/retarder).
Under the sheathing vent channels may be a well proven, code compliant option.
达娜，
感谢您的信息。看起来还有很长的路要理，可以了解进出口。还有更多的吸收比我理解的。但是，通过做部分通风，真的似乎在封装的收益中真的似乎已经陷入了足够的凹痕，这让我想知道一个人是否应该做到这一点。每种情况都不同，但似乎正在做旧时尚的排气屋顶，并使用埋地管道或螺旋管道，使管道内部的管道。我在爬行空间中的管道上没有看到过多，我认为可能是一些解决方案。