当然，吹墙腔时外部刚性泡沫可能是一个好主意，但有必要吗？
我的1920年平台框架房屋位于气候区5＆6的边界。
The empty wall cavities are framed with true 2x4s, 16 OC. Walls are covered with lathe and horsehair plaster on the inside and 1″ pine sheathing boards outside. The current siding is a horrendous installation of vinyl over the original clapboards. The cavities are now empty.
我们打算拆下乙烯基（仔细，重新使用），剥离拍板，宽松的墙体，将房屋包裹在焦油纸上，并恢复乙烯基。
Well, what about adding exterior foam? Do we HAVE to, in order to avoid condensation? Yeah, I get it…. adding foam either inside or out will lower thermal bridging, and provide better overall performance. And I understand that once you add ANY foam, you introduce a whole new set of factors in terms of moisture-control and key once you add any is to make sure you add ENOUGH. If we add foam, we’ll go with 1.5″ XPS, which I think gives the required R 7.5 for zone 6.
But what about just living with the thermal bridging and lower performance and SKIPPING the foam? Is that a recipe for soaking our sheathing and cellulose, assuming the interior and exterior planes are doing their respective water & moisture jobs?
Thanks
答复
首先，您从未实际凝结过冷，水分以吸附的形式进入木材，而不是液体。
松工具有比OSB或胶合板更高的蒸汽渗透性，因此它比这些材料更快地干燥。通过固有的后退乙烯基壁板，毫无疑问，即使只是乳胶涂料作为内部蒸汽延迟器，它也可以从内部水分驱动器中得到充分保护。在第6区的温暖边缘，也没有特别危险。如果致密包是纤维素，而不是玻璃纤维，则应在第6区的任何地方都很好，尽管它在技术上是违规的代码，除非内部涂料具有小于1倍率的蒸汽渗透。
但是内部涂料是否具有较小的烫发的蒸汽渗透性？
If it's old enough to have horsehair plaster, it probably has multiple layers of oil based paint, which would be WELL under 1 perm! And that may be a whole other issue in your wall stack-up decisions.
湿度控制的关键因素是闪烁到漏平面层的窗口和门的条件和研磨，这是您可以评估和修复的东西，如果您将其剥离到板条护套上。
但是，也有低热能问题。真实4“深度的额外r由全宽2”宽铆钉的较大框架分数偏移 - 由于框架额外的框架，除了较高的框架，除非是较高的框架一个气球框架多层，窗口和门标题是单身而不是双层木材。
如果您是厚度约束，则R6-ISH 1.5“刚性岩棉溶液将优于R7.5-ISH XPS溶液，因为在1.5”下，XPS对于具有多层油漆层的墙壁可能过于气密。在内侧。刚性岩棉羊毛板超过25个烫发，并且不会以任何有意义的方式抑制到外部的干燥 - 有更多的空间紧密比（！）。
如果您不受厚度约束，则仍然可以肯定是最多2.5英寸未允许的II型EPS，这将超过1倍的干燥能力进入乙烯基壁板的空气中。
The 1" rock wool solution would make IRC 2012 code-min for whole-wall performance in zone 5 but not zone 6. With 2.5" of EPS (or 3" of rock wool) it would meet IRC 2012 code min for zone 6.
如果你把1.5英寸的EPS放在那里（比摇滚羊毛或XPS便宜），它将运行R6.3标称，但在冬季户外平均水平期间R6.8-ISH仍然足以进行露点控制区域6的温暖边缘（尽管技术上是一种代码违规，除非内部在1个烫发之下），但它将有1.5-2个干燥能力的烫发容量，仍然很好。1.5“XPS，您将在0.6 -0.8允许，这有点紧。
Mark,
My answer will be briefer than Dana's.
不，在本申请中不需要外部刚性泡沫。
There is no reason to worry about moisture problems in your sheathing, due to the fact that the board sheathing is vapor-permeable, and due to the fact that vinyl siding is so well-ventilated. Don't worry about the multiple layers of interior paint; I have never seen a house like the one you describe with diffusion-related moisture problems at the sheathing level. (If your house ever gets moisture problems at the sheathing, it will be due to flashing errors, not vapor diffusion.)
Thank you very much, Dana and Martin