SIP flat shed roof vent channel
Sorry another SIP roof question, I’ll try to be brief!
Having read a number of articles, namely (//m.etiketa4.com/article/is-this-sip-fore-in-trouble)
I am unclear if my low-slope application should have a vent channel above the SIP panels. My SIP supplier here says SIPS are always ‘cold’ roofs and to install a vented channel with furring strips and 3/4″ ply over the SIP panel but given my understand that flat roofs like this don’t vent properly (from Martin’s other flat roof articles), is this necessary? Or can I just adhere the EPDM to the SIP OSB?
Details:
- 位置是英国的SW海岸，我想说4C气候区，尽管冬季可能在现实中变暖
– Proposed 8″ SIP roof panels with EPDM rubber roof on top
– Roof is 1/12 mono pitch shed, 23ft wide by 14.5ft (this is a small holiday home)
我知道这里的许多人不是SIP的粉丝，但是该地点的细节意味着携带所有材料的路径上有300码的步行路程。我和机组人员可以在两天内安装SIPS，而不是拖延框架材料，绝缘材料，镀金等（如果不是用于现场位置的话），否则是我的首选方法）。
高规格的空气/蒸气磁带可容易获得，并将在所有面板接缝的空气密封中使用，板上的泡沫，接缝等。再加上建筑物很小。
Of course, if the consensus is that the SIP roof approach is risky, I could frame the roof ‘traditionally’, probably 2x8s, ply deck and 2″ of closed cell spray foam the underside balance filled with rockwall.
You advice greatly appreciated.
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答复
Quinn,
You may find that there are many people in the GBA community who are not fans of SIPs, for various reasons from how tricky they can be to detail properly to unfortunate experiences with manufacturers. But that's not to say that they can't be an effective option.
的确，低倾斜的屋顶不会像陡峭的屋顶那样发泄，但是在您的情况下，这不是建造通风口通道并添加额外屋顶甲板的原因。继续进行这项工作的原因是因为EPDM膜不允许SIPS干燥到外部。您可以使用应用于SIP OSB的透气膜，构建通风口通道并将EPDM应用于新的屋顶甲板，并假设您已经完成了所有必要的空气密封并很好地闪烁，则具有高效且健康的SIP屋顶。
如果您愿意考虑框架，密封和绝缘屋顶的其他选择，我敢肯定，这里的社区将愿意帮助您考虑自己的选择。
Here are a few links to try for more information that may be helpful:
//m.etiketa4.com/article/how-to-make-a-sip-froof-better
//m.etiketa4.com/article/sips-are-are-they-right-for-your-next-project
//m.etiketa4.com/question/best-detail-for-epdm-on-sip-roof-second-try
//m.etiketa4.com/article/insulating-low-slope-residential-roofs
> EPDM membrane won't allow the SIPs to dry to the exterior.
If you could block all airflow from the interior side, then EPDM (.43 perms if below is correct) would provide some drying to a 8" SIP (also about .43 perms). More important are the general concepts:
a) the amount of drying needed is completely dependent on the amount of wetting
b）空气流比蒸气扩散更大的关注点
c）通风口通道提供相对较大的干燥（即使在低坡屋顶）
http://rci-online.org/wp-content/uploads/2001-09-kirn.pdf
Impermeable materials under 1 perm are classified as vapour barriers. How would you get any drying through something with a 0.43 perm?
I am planning on building a small cabin in western Canada using a SIP roof, and also a SIP floor
（墙壁将是常规的棍子框架）。我的屋顶将在sip屋顶上方有一个冷屋顶，包括：外饮护套表面 - 所有接缝胶带，30磅的建筑纸，2x4毛茸茸的条，3/4“胶合板护套，火膜，站立的接缝金属屋顶。沿着河口和山脊沿着通风条带有通风条的简单棚设计。
The other nice thing about a cold roof design is that it provides another layer of defense between the weather and the SIP sheathing. I am curious as to what breathable membrane Brian would recommend for the SIP sheathing surface.
Hi Scott,
Here's one product that I know I've seen recommended by others on this forum and I know lots of builders and architects that speak highly of Siga products in general:https://www.siga.swiss/global_en/catalog/majcoat
感谢布莱恩的详细信息。非常感激。
For what its worth, I got a detail from the SIP supplier today too, its in metric but same idea! Though I think the poly vapour barrier proposed here would be shunned upon based on what I've picked up from GBA articles.
I used SIGA Majcoat on my low slope SIP roof.
Peter,
这是您在两层房屋上的线程中谈论的相同观点吗？我明白你为什么喜欢住在那里。
Malcolm,
Yes. The area and views are quite amazing. It's at 5,000 feet elevation in a Zone 4B climate. Lots of juniper and pinion pine. Deer, javelina, mountain lion, bobcats, badgers, even elk in the wintertime can be seen in the area.