答复

1. 
   查理·沙利文（Charlie Sullivan）|2015年8月11日下午09:55|＃1

   My initial answer is that this would not be a good design for the reason you suggest. But you would get better answers with your climate zone or zip code included.

2. 
   约瑟夫携带|2015年8月11日下午10:41|＃2

   气候区5。

3. GBA编辑
   Martin Holladay|2015年8月12日上午04:54|＃3

   约瑟夫，
   您的墙件组件会起作用 - 但不要期望向内部干燥到2英寸的Polyiso。

   有关此类型墙的更多信息，请参阅带有内部刚性泡沫的墙壁。

4. 
   约瑟夫携带|Aug 12, 2015 06:51am|＃4

   谢谢查理和马丁。
   I am not expecting any drying through the 2" of poly-iso. My thinking is that the back of the sheathing will be protected from outward vapor pressure and will dry to the exterior if the weather gets in. Any condensation from outward vapor pressure, it seems to me, would happen on the studs because of thermal bridging--so the interior edges of the studs could fall below the dew point and cause problems. But maybe that doesn't really happen. It seems to me that what I am doing is not all that different from a flash and batt technique, or a so-called hybrid wall assembly. I have enough impermeable and air tight insulation (I am taping and foaming all seams of the poly-iso) to the exterior to push the dew point out of the cavity at the sheathing and fill the rest with lower cost cellulose. Again, my concern is cold spots on the framing members that project into the cavity past the poly-iso.

5. 
   Reid Baldwin|Aug 12, 2015 06:56am|＃5

   我不认为约瑟夫在谈论将Polyiso放在墙壁的内侧。取而代之的是，他正在谈论将其放在护套的内侧。如果我正确理解，那将不是连续的绝缘材料。它只会在螺柱腔中，因此每个腔具有2英寸的多叶和7英寸的纤维素。

6. GBA编辑
   Martin Holladay|Aug 12, 2015 08:31am|＃6

   约瑟夫，
   抱歉 - 我误解了您的问题。我现在意识到您正在谈论使用“剪裁”方法。（我认为。）有关此技术的更多信息，请参阅切割的绝缘材料。

   In your climate zone (Zone 5), the method you are contemplating (a combination of exterior rigid foam and air-permeable insulation in walls) will only work if the R-value of the rigid foam makes up at least 27% of the total R-value of the wall. (If you're unaware of this, you might want to read计算刚性泡沫护套的最小厚度。)

   Assuming that your stud depth is a true 9 inches, then your R-11 polyiso represents about 30% of the R-value of your R-37 (nominal) wall -- so you are OK on the issue of moisture accumulation.

   Of course, cut-and-cobble has its own disadvantages, which you can learn about when you read the article on the cut-and-cobble method. In all cases, a continuous layer of exterior rigid foam is preferable to thin strips of rigid foam inserted between your studs.

7. 
   查理·沙利文（Charlie Sullivan）|2015年8月12日上午10:22|＃7

   你的螺柱是什么样的？仅1.5英寸x 9英寸的实木，还是工程木头的梁？还是双层墙？

   马丁说,我连续层绝缘s better. That's both because it avoids the degradation of R-value, and because the thermal bridging will mean that the studs poking through the polyiso will be colder than the polyiso and could possibly have condensation problems. I don't think that's terribly risky, because with the membrane on the inside, you won't have much moisture going in, and any moisture on the studs can diffuse through them and out to the exterior. So it might be OK, but it's non-standard and not 100% bulletproof. Sometimes modeling with the "WUFI" simulation program can give insight on a non-standard configuration like this, but WUFI only does 1D, whereas what you want to understand is the 2D effect of having the studs bridging the polyiso.

   如果您做双柱墙，则可以选择将某种空气屏障/蒸气阻滞剂放在中间。那可能是您的polyiso，或OSB或某种膜。然后，您必须用纤维素填充内部和外部，这听起来像是一种疼痛，但是根据我的经验，无论如何，非专家隔热材料都在深腔中遇到麻烦，并且填充两个浅腔可以更容易。然后您可以跳过内部的膜。

   如果您正在进行工程的I梁，则可以考虑将Polyiso稍微放在中间，以便适合I-Beam薄的位置，并且没有太多的热桥。

8. 
   约瑟夫携带|Aug 12, 2015 11:04am|＃8

   Yes, "cut and cobble" is what I had in mind. I apologize for my lack of clarity. I will check out the article by that title.

   我有一个现有的墙腔，具有真实的2x4结构。2英寸的poly被切割并在海湾内鹅卵石（胶带和泡沫）。我的计划是用2x4构建。因此，实际上，我只有一个7.5英寸的腔体给我更大的余地，因为外面绝缘百分比的错误我的水分/空气屏障（R-11的名义总计R-32）。我的进一步问题是：我是否最好在现有的螺柱上垂直运行2x4毛茸茸并最大程度地减少热桥接，或者我将它们更安全地覆盖到现有的螺柱上，以使热桥保持螺栓保持螺柱的热量？

9. 
   查理·沙利文（Charlie Sullivan）|2015年8月12日上午11:56|＃9

   因此，切割和鹅卵石已经完成了吗？这会稍微缩小选项。但是，如何在现有墙壁（内部）上获得1英寸Polyiso（或EPS）的一层，然后将2x4添加为从现有的螺柱上添加1英寸的额外厚度，由Polyiso的额外连续层添加。？该层可能是您的空气屏障，也可以解决热桥接问题。如果您不想要额外的厚度，则可以使用2x3的内部螺柱。并且不需要内膜。