Mineral wool and vapor barrier in zone 4A home?
I really appreciate this community and everyone’s patience helping me better understand our best approach with this new home. I hope this doesn’t sound too dumb, but I feel compelled to “make sure” I don’t end up with a serious uh-oh-oh. I’m at the bottom of the 4A climate zone in Tennessee next to the Alabama/Georgia intersection. We are considering using mineral wool in this new home and typically, we don’t worry with vapor barriers here. However, as I was reading an article in GBA (link below), the vapor barrier was mentioned several times for the cooling season. If I install mineral wool in this climate zone, is a vapor barrier necessary?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
>“如果我在这个气候区安装矿棉，是必要的蒸气障碍吗？”
不可以。外护套和室内墙板的气密性比这些层的蒸汽滞后更重要。一个“聪明”的蒸汽延迟器，如2-mil尼龙（Certaineb膜），在墙板后面可以提供很多弹性，如果您是令人担忧的令人担忧的类型，可能是值得的。
If the siding is a brick or stone veneer it may be worth reducing the vapor permeance of the exterior sheathing to reject the intense moisture drives when the sun hits rain/dew wetted masonry, but not with a true vapor barrier, unless it's on the EXTERIOR of the structural sheathing. Even a half-inch of foil faced polyiso would protect both the exterior sheathing and the studwall cavities from exterior moisture drives, as well as offering an R3 thermal bridge over the framing fraction.
I'm assuming the proposed wall is 2x6/R23?
谢谢达娜。我们正在外观上使用拉链护套。我打算在Hardi壁板（一组板和板块和雪橇和雪松摇动）之间使用3毫米的雨水，以减少任何静水压力，并使能够更好地干燥组件。然后矿物羊毛在16“中心的2×6框架中确实是R-23。唯一的石头将是底部基础墙壁部分的天然石材贴面，其浇筑混凝土。
Btw... you said "Air-tightness of the exterior sheathing and interior wallboard matters a lot more than the vapor retardency of those layers". That reminded me that I've seen somewhere that the wallboard can be sealed once put up, and I think before the plaster is applied. I believe I've also read that latex paint can serve as a good barrier. So, with that said, would it make more sense to ensure they are sealed well and painted in lieu of a vapor barrier? If so, what's the best approach for sealing the wallboards then?
使用胶带和斗篷搭配Zip，它非常紧密，并且足够蒸汽延迟，而不是为空调家用的Studwalls提供夏令的湿度问题。如果没有WRB FALIER，OSB在干燥时运行少于1个烫发，即使具有相当高的水分含量（它永远不会有5个烫发）。
Standard latex paint on wallboard or plaster runs about 3-5 perms, which is just what the doctor ordered for an interior side vapor retarder in a zone 4A climate.
在将干墙细节为空中屏障的底漆，请参阅：
https://www.finehomebuilding.com/2010/09/09/airtight-drywall
It's not rocket-science, but rather goop-science + better/tighter electrical boxes. In a zone 4 climate it's more forgiving than in a zone 6+ climate, but giving it some amount of effort will be worthwhile. Polyurethane sealants are a lot nicer than some of the acoustic sealants people were using in decades past.
谢谢达娜。Sounds like I'm going the right direction here. You mention the "Polyurethane sealants are a lot nicer than some of the acoustic sealants..." What are the major breakthroughs and products worth considering? It seems every time I look up sealants online, acoustic still pops up due to its drying and cracking properties (or lack of). And I'm sure there's good and bad products out there, but it would be nice to have a couple ideas to benchmark from.
另外，良好的文章。绝对是一种更集中的空气密封方法。
>"What are the major breakthroughs and products worth considering? "
目的是制造了非常低的膨胀泡沫密封剂，用于蝙蝠绝缘，如knauf Ecoseal或Owens Corning Propink Cheetseal比通用声学密封剂更少于臭粘性，并且比普通水固化罐 - 泡沫更柔韧，穿透裂缝和接缝。/枪泡沫。Proseco R-Guard接头和缝填料（填缝，而不是泡沫）也是非常好的东西。
I'm not sure any of these products qualify as "...major breakthroughs..." , but it's incremental progress to be sure.