答复

1. GBA编辑
   Martin Holladay|2017年5月2日02:26 pm|＃1

   罗索，
   您住在气候7，这很冷。只要刚性泡沫的最低R值为R-10，就可以添加外部刚性泡沫。这意味着2英寸的XPS或Polyiso或2.5英寸的EPS。

   如果您想安装蒸汽渗透的绝缘材料，则可以使用连续的矿物羊毛层。如果使用矿物羊毛，则可以选择想要的任何厚度。当您使用矿物质羊毛时，没有最小的R值。

   以下是几篇文章的链接，其中包含有关这些问题的更多信息：

   计算刚性泡沫护套的最小厚度

   How to Install Rigid Foam Sheathing

   用岩石丝网包裹旧房子

2. 
   杰里米（Jeremy A）|2017年5月2日02:52 PM|＃2

   我希望我可以跳入这个线程。

   马丁,我在墙有2 x6 r-19气候佐恩e 6 with an interior polyethylene barrier. If i put 1-1.5" of roxul comfort board on when residing, I wouldnt have to worry about the dew point causing moisture issues on the plywood sheathing?

3. 专家成员
   达娜·多塞特（Dana Dorsett）|May 02, 2017 03:36pm|＃3

   Jeremy: With the polyethylene sheeting you already don't have to worry about dew point issues, since you've blocked the diffusion path from the humid interior to the cold sheathing. Adding vapor permeable insulation such as rock wool doesn't make it any worse, it only makes it better.

   仅1.5英寸的摇滚羊毛不足以跳过内饰上的聚乙烯（或其他低温蒸气延迟），但是只要它具有一个水分，只要它具有一个水分，只要它具有一个水分，只要它具有一个水分含量干燥路径通往外部。

4. 
   罗索|2017年5月2日04:16 pm|＃4

   因此，我阅读了以前的博客，我了解水分等问题，但是我提到的渗透性泡沫板又如何提到了Ener-air。它的perm级额定值为60，而Tyvek的Perm率为57，所以在我看来应该这样做。充分向外部排出水分？这是一种相对较新的产品，与箔纸的东西不同，它不可渗透。我仍然应该将其绑在泡沫上？

5. 专家成员
   达娜·多塞特（Dana Dorsett）|2017年5月2日04:29 PM|＃5

   Yes, high-perm foam exists, and should work fine, but it's a specialty item.

   https://www.iko.com/na/publication/ener-air-brochure-2/wppa_open/

   是的，您仍然需要至少在高层泡沫和壁板之间至少有一定数量的通风空间，以便有一条良好的干燥路径通往外部。

6. 
   杰里米（Jeremy A）|2017年5月2日下午10:57|＃6

   I was under the impression there was a minimum r value suggested when adding exterior insulation. Good to know i can add some during my future re-side. I would prefer to add more but my roof overhang at the gable ends is only a couple inches

7. 专家成员
   达娜·多塞特（Dana Dorsett）|2017年5月3日下午12:02|＃7

   最小的外部R仅在外部绝缘材料的蒸气渗透量低并且没有内部聚乙烯时才需要。

   If you have the interior polyethylene keeping to the minimum is still a good idea with exterior insulation that has low vapor permeance (like most rigid foam), but rock wool doesn't have that problem, but most rigid foam. With low-permeance exterior insulation it creates something of a moisture trap, but as long as the temperature of the sheathing is warm enough, it (usually) stays dry enough.

   If there is no interior vapor retarders (defined as < ~1 US perm in Canadian building codes) the minimum exterior R is mandatory even if it's high permeance insulation. This is because the plywood or OSB sheathing itself has too a low vapor permeance, and will accumulate moisture coming from the home's interior if it's too cold, even when there is a drying path toward the exterior.

8. 
   杰里米（Jeremy A）|May 03, 2017 01:16pm|＃8

   谢谢Dana，我想在我的情况下，使用Roseau提到的Polyiso Ener-Air产品之类的东西将更有意义。它将为我的有限空间提供更多的R值。