Replies

1. 
   riolsong.|Apr 18, 2010 01:59pm|＃1

   As you suggest, it's often far more important to understand the liabilities of a building material than its assets.

   除了极易易受无聊的昆虫（例如白蚁和木匠蚂蚁）外，如果没有受到适当详细的金属昆虫的保护，塑料泡沫也容易受UV降解，物理损伤和火灾。

   They also have a very high embodied energy and embodied global warming liability, as well as significant environmental life cycle impacts as well negative health effects. Plastics of any kind also remove negative ions from the living space - electrically-charged particles which are essential to both physical and emotional health.

2. 
   Interested Onlooker|Apr 24, 2010 05:11am|＃2

   Thank you Robert for so clearly voicing my own concerns about the advisability of foam-based sheathing. I wonder whether a variation on the 'advanced framing' technique which keeps the air barrier at the outer side of the envelope might be possible. I am somewhat concerned that the air-tight drywall approach which you favour might have long-term durability problems once the house has changed owner and the desire for modifications kicks in.

   What I am considering is, from the outside in :

   壁板 - 液体水的脱落
   Firring – create a drainage route
   Vapor-permeable housewrap – drainage plane and air barrier
   护套 - 结构和空气屏障（胶合板优选）
   6 x 2框架 - 结构
   2 x 2水平击球 - 一些结构加热断裂
   2 x 2立式击球 - 支持干墙
   干墙 - 不气密

   护套和干墙（10英寸标称）之间的整个空间填充有致密包纤维素，用于绝缘，进一步的空气控制和防火

   If demanded by code a single vapor barrier could be placed at one on side or other of the sheathing.

   I would appreciate any comments on this proposal.

3. 
   br|2010年4月24日02:59 PM|＃3

   谢谢，罗伯特，为了响应。我看到的问题是闪烁是最常见的细节之一，即使是天气，甚至是天气，更不用说害虫。事实上，我发现木匠蚂蚁的场合与缺乏闪烁允许水分腐烂而腐烂的木头。我确定蚂蚁最初被腐烂的木头吸引，但是一旦他们发现泡沫，他们将它视为设置家庭的一个非常容易的地方。与所有建筑一样，对细节的关注至关重要。

4. 
   riolsong.|Apr 24, 2010 08:08pm|＃4

   Yes, Brian, carpenter ants are an indicator species - they indicate where the leaks are, since they will invade only wet wood.

   旁观者，该系统将工作，除了它使用大量的木材来制作深墙。您可以获得更多的R值，使用双壁方法更少的热桥接和更少的木材。只要顶部和底板的所有孔都密封，外部空气屏障很好。大多数空气运动并不是直接穿过墙壁，而是通过孔，裂缝和缝隙隙中垂直（堆叠效果）。

   因为我为寒冷的气候建造，所以我更喜欢室内空气屏障的原因是因为冷凝的唯一电位来自温暖的内部空气向外移动到热封的较冷层。冬季渗透不能造成凝结，只有救生。

5. 
   Interested Onlooker|Apr 25, 2010 04:31am|＃5

   罗伯特，谢谢你常见的深思熟虑。如果有10英寸的致密包纤维素，然后是密封的外护套，则不了解内部空气的抗滤网。蒸汽扩散，当然是，但实际的exfiltation以大量的数量为单位？

6. 
   riolsong.|2010年4月25日11:54 AM|＃6

   Onlooker,

   密实充填纤维素可以显著降低空气移动ment compared to fiberglass, but does not meet the air barrier standards of the AABA. Another major difference between cellulose and fiberglass is that the former will absorb much of the moisture in any air that moves through it, whereas fiberglass will allow it to continue on to find a condensation surface.

   The most dangerous air movement in a thermal envelope is what's called "channel flow", in which air enters in one location (e.g. an electrical outlet) and moves within the envelope until it can find an exit in a distal location (e.g. an unsealed mechanical hole drilled in the top plate). This gives the moist air more time and more surface contact within the envelope to allow condensation or absorption.

   即使存在“完美”的外部空气屏障（没有完美的东西），墙壁内有孔或底板上有孔或间隙，那么通过任何纤维绝缘将存在空气运动。无法预测到多少是多少，但将通过孔口，内部和外部温度，堆叠效果压力，由于机械系统而导致的空气压缩性，以及风速和方向来确定。

7. 
   John Brooks.|2010年4月25日12:33 PM|#7

   riolsong.:"but there are holes or gaps in or around the bottom and top plates within walls,"

   罗伯特，这似乎非常类似于密封的干墙情况。
   The drywall layer itself is easy enough to make airtight with mud and paper... it is where the drywall "stops" that a special transition is needed to connect the drywall to the framing or the "whatever"....

   为什么我们不能与结构护套做同样的事情？在过渡时使用垫圈或合适的密封剂？
   This "AIR" is under pressure and we need to appreciate that it will seek a path.

   那么为什么气密护套方法（ASA）可以不那么可靠，而不是气密干墙方法（ADA）？
   ASA seems to be achieving better blower door results than ADA

8. 
   riolsong.|2010年4月25日01:45 PM|#8

   约翰，

   I think you're missing my point. I was referring to the cold-weather problem of indoor moisture-laden air exfiltrating into the thermal envelope to create a condensation potential and consequence moisture problem.

   If the condensation problem comes entirely from the inside, then the inside surface is the ideal place to arrest the air movement. If you're in an air-conditioning climate with reverse condensation potential, then the sheathing is the appropriate place to arrest the air.

   Either system can be done effectively. For me, the goal is NOT to maximize air tightness (I prefer house that leaks a little, so that it can exchange air without mechanical assistance, such as with passive air inlets), but to reduce to insubstantial the moisture threat within the thermal envelope.