答复

1. Expert Member
   Dana Dorsett|Nov 11, 2019 05:35pm|#1

   >"I’m right on the border between zone 6 and 7"

   这意味着，鉴于气候变化率，到2050年，您可能是在第6区的中间。如果使用本世纪的天气数据而不是20世纪已故的数据，您可能已经在第6区。

   >“我已经将墙壁绝缘到r 39附近”

   是使用2x12螺柱，双拔牙或...的R39？

   >“...... R76和R96之间的建筑业绩会有很大的实际差异”

   A whole-assembly R of R75 would be about the maximum that's financially rational for zone 6, so even though it's cheap that last 5-6" isn't buying you much, so there's not much point to piling it on all the way to R96. See Table 2, p.10:

   https://www.buildingscience.com/sites/default/files/migrate/pdf/ba-1005_high%20r-value_walls_case_study.pdf.

   (Read the whole first chapter.)

1. 
   vt_guy.|Dec 25, 2021 10:25pm|#7

   How are you calculating projected fuel costs over what time period to arrive at what is “financially rational for zone x”?

2. 
   Smokey059.|Nov 11, 2019 06:18pm|#2

   我读了链接，我看到R75会很好。为重量进行准确的数字是否准确？
   就墙而言，我刚刚在墙壁组件中添加了每层的R值。我不知道真正的r值。墙壁是2x6，填充roxul，然后是填充到框架的胶粘层。然后2英寸的箔面配有接缝，然后镶嵌1x4捆扎，最后是板衣。我也坐在罗疹进去之前镶嵌了螺柱海湾。所有电器盒都在胶合板空气障碍之外。墙壁应该是气密的，但是不知道真正的价值。热桥应由多自然破裂。谢谢你的链接

3. Expert Member
   Dana Dorsett|11月11日2019 07:13 PM|#3

   即使在最坏的情况下，开放玻璃纤维素几乎总是在每立方英尺处或下方2磅下方或下方的2磅下，如果遵循制造商的鼓风机设置，通常在1.5磅以下。在初始吹的初始吹气时，逼真的数字将是每立方英尺的1.5磅，或者在沉降后的比特密集，或2磅作为最坏情况NU

   一个12层的纤维素是一种运行bout R40-R45, so 2 feet deep (R80-R90) would be 3-4 lbs per square foot and initially R80-R90. An initial blow of 24" will settle to about 22" over the first decade or so and very little thereafter, which would be the R75 to R80 target range you're looking for. Call it 3lbs per square foot if everything is nominally set up correctly, 4lbs per square foot if it's off. Some installers intentionally shoot for 2lbs per cubic foot nominal density to limit the amount of settling over time, but it's quite a bit more material, and not really necessary. A 1.3-1.5 lbs density initial blow is about right for most.

4. 
   Smokey059.|11月11日，2019 08:49 PM|#4

   再次感谢Dana为细分使得更容易理解。所以即使我没有得到完美的吹气密度，我仍然只能进入4磅PSF，因为初始吹来的24“，添加到胶合板，捆扎和锭剂将在7psF附近。有10psf底线止返我应该在安全限制范围内。
   On a side note I read today on this site the penalty of just a small area of the insulation depth being less than the desired depth and how it brings down the overall r value of the whole assembly. The trusses on this structure were raised heel but not to a 24" depth. I think their 8". I did cover the top plate for its 5.5 inches to that 8" height with pieces of xps and foamed them in leaving the 2" for the soffit vent chutes but that still leaves another maybe 12 to 14" along the eaves that will not be 24" deep of cellulose. Could I extend those foam pieces out a distance to bring this area to the same r value as the 24" of cellulose. This area that's less than the 24" needed for full cellulose depth is approx. 60 sq ft of the total 2000 sq ft structure. How bad of a penalty is this going to be? Is it worth adding some ridged foam in these areas before the cellulose goes in. Thanks.

1. Expert Member
   Zephyr7|Nov 11, 2019 09:51pm|#5

   尝试过这样做（用刚性泡沫周围的顶板拳击），我可以告诉你，没有泡沫分开，令人惊讶的是难以做到的。使用Dana的数字的纤维素比每英寸R3.5更好，XPS额定R5每英寸，但随着时间的推移，性能较低，所以让我们说每英寸R4.5。您可以使用刚性泡沫添加约R1，但您可能会产生空隙，并有一些碎片松动。你的整体收益是多少？可能什么都没有;也许甚至是消极的。

   我用刚性泡沫以平常的方式构建挡板，以防止风力洗涤，然后在顶板上尽可能地享用吹制绝缘的盖子。吹绝缘体具有非常良好的符合不规则表面的优点，因此它更不可能留下任何空气间隙，其中性能抢劫对流气流可以流动。

   If you can get to the top plate, it would be worth double checking that you have everything well air sealed though. A small air leak can rob you of a LOT of insulating performance!

   Bill

5. 
   Smokey059.|Nov 12, 2019 10:37am|#6

   Thanks for the input. I guess ill just double check for any leaks around the top plate and then fill with cellulose since extending foam out won't really gain anything. Ill have to live with a little less r value over that area. Thanks again for the help