密集包装的干纤维素：有缺点吗？

CSS1813|发布绿色产品和材料上2018年4月16日上午10:26

I’ve been going over insulation techniques to use on a new home. Every insulation contractor that we’ve talked to has a different system. One in particular that is being pushed is dense pack dry cellulose. I have personally witnessed wet cellulose settling in our own home, however based on everything I have read about and heard about dense pack is that it will not settle and that our current home’s insulation was not installed properly. I know that cellulose is somewhat springy so I understand the theory is it will hold true in the wall for hopefully many many years. The contractor that is pushing it uses a netting type of material to hold in the dry cellulose until the drywall is up.

那时我的问题是，致密干燥纤维素的缺点是什么？到目前为止，我唯一见过的是，任何接触水分都会导致其沉降或凝结。但是，我的看法是，如果您的墙壁上有那么多水分，那么您可能会有更大的问题。我很好奇一些公正的专家在这方面要说的话。

我住在密歇根州。第5区。房子的外部将有1/2英寸的护套，带有Tyvek的常规房屋包装，并在其上面有乙烯基壁板。内部是标准的1/2英寸干墙。

Thank you so much for the valuable information on this website.

克里斯

回答

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Replies

专家成员

Dana Dorsett|Apr 16, 2018 11:09am|#1

使用致密的包装，沉降取决于正常的季节性水分循环和密度。水分循环会产生蠕变问题，导致其沉降，但它不会发生。所需的密度随气候和墙壁组件的细节，室内和室外季节性相对湿度等不同而变化。在区域5气候下，每立方英尺3.2磅或更高，但3.5磅或更高，但通常为3.2磅或更高在某些条件下，可能在第5区的冷边缘需要要求，因此要射击3.5磅。虽然某些安装程序和鼓风机可以击中4磅，并且在您的位置不太需要。

With vinyl siding and 1/2" OSB or plywood code doesn't require in interior side vapor barrier to protect the sheathing in zone 5, but a "smart" vapor retarder such as 2-mil nylon (eg Certainteed MemBrain), or Intello Plus under the wallboard will most likely result in lower peak and average moisture content in both the cellulose and sheathing.
GBA Editor

马丁·霍拉迪（Martin Holladay）|2018年4月16日上午11:20|#2

克里斯，
Dense-packed cellulose is an excellent insulation choice for closed cavities (for example, stud bays). It has low embodied energy; a high recycled content; reduces infiltration and exfiltration; and fills odd-shaped spaces perfectly.

The only downside I can thick of is that in some regions of the country, it can be hard to find an insulation contractor with dense-packing experience. In these areas, the cost of dense-packed cellulose, if it is even available, may be higher than other options.
lance_p|Apr 16, 2018 11:24am|#3

达娜（Dana），是否有针对不同气候区和/或预期低温的推荐纤维素密度图表？我处在CZ6A的寒冷一面，并为墙壁组件计划一个密集的包装。根据我到目前为止阅读的内容，我打算至少达到3.7磅/铜的速度，但是如果我没记错的话，这是一个非常普遍的建议，而不是专门与气候区域绑在一起。

I thought, and once again I may not be remembering incorrectly, that the 3.7 lb/cuft recommendation had come after shaker/vibratory and climatic testing of wall assemblies in Europe? I don't remember where I read that. Either way, I was planning to go a little above just to be safe.
CSS1813|2018年4月16日上午11:26|#4

谢谢你们，一如既往地感谢您的所有帮助！
专家成员

Dana Dorsett|2018年4月16日下午12:08|#5

兰斯（Lance） - 我不知道是否有人在此上汇集了图表 - 有很多因素，而且大多数研究都在欧洲进行。丹麦阿尔堡大学的TorbenValdbjørnRasmussen已发表了几篇有关该主题的科学论文，可以追溯到20年左右：例如：

https://www.researchgate.net/publication/245382436_Verification_of_Density_Predicted_for_Prevention_of_Settling_of_Loose-fill_Cellulose_Insulation_in_Walls
专家成员

迈克尔·梅纳斯|2018年4月16日下午12:22|#6

我从纤维素大师Bill Hulstrunk中学到的是，所需的密度与腔体的大小有很大关系。腔体越大，需要吹出纤维素的密度，在12“ x 24”腔中最多可吹4.0 pCF或更多。循环润湿将使纤维素压缩一点。在最近的NESEA会议上，建筑科学公司的Kohta Euno展示了他们正在进行的测试图像，其中纤维素已安装在未通风的屋顶中，在饱和后远离屋顶护套。因此，尽管纤维素不应该安顿下来，但在某些情况下确实如此。但是，在具有不错的水分控制的2x6腔中安装应该是安全的，通常建议至少3.5 PCF。在3.8 PCF的密度下，每英寸的R值开始下降一点，尽管在大多数情况下还不足以重要。
lance_p|2018年4月16日下午03:09|#7

Interesting. Their research suggests 50-80% RH swings at 23C require about 4.5 lbs/ft3 (73 kg.m3) for a 12" (0.3m) wall cavity, and about 3.9 lbs/ft3 (63 kg/m3) for a 6" (0.15m) wall cavity.

我正在做12英寸的深腔，因此看起来要瞄准4磅/ft3以上是谨慎的。谢谢您的链接！！！
lance_p|2018年4月16日下午03:14|#8

Michael, this publication by Joe L. suggests dense packing a flat roof is seldom a good idea without some sort of rigid insulation attached firmly below the roof, or spray foam:

https://buildingscience.com/documents/insights/bsi-043-dont-be-dense

听起来像Bill H.是根据Dana引用的论文的正确性。我想我会拍摄超过4磅/ft3的安全性。
GBA Editor

马丁·霍拉迪（Martin Holladay）|2018年4月16日下午03:39|#9

槊，
It's not just Building Science Corporation that advises readers that dense-packing rafter bays only makes sense if either (a) there is a ventilation channel between the top of the cellulose and the underside of the roof sheathing, or (b) there is an adequately thick layer of closed-cell spray foam between the top of the cellulose and the underside of the roof sheathing, or (c) there is an adequately thick layer of rigid foam above the roof sheathing.

长期以来，该建议也一直是GBA的标准建议。有关更多信息，请参阅这两篇文章：

How to Build an Insulated Cathedral Ceiling

绝缘低坡度的住宅屋顶
专家成员

马尔科姆·泰勒（Malcolm Taylor）|Apr 16, 2018 07:42pm|＃10

马丁，

Réponse回答了这里讨论中出现的许多问题：
//m.etiketa4.com/blogs/dept/qa-spotlight/does-fore-fore-need-breathe#comment-form

但是，如果您有机会，我将感谢您对排气处高于护套的效率和机制的看法。
GBA Editor

马丁·霍拉迪（Martin Holladay）|2018年4月16日下午08:04|＃11

马尔科姆，
在GBA上的屋顶护套上方有一些讨论。最好的设计是用2x4s创建的，安装了“平坦”，以创建1.5英寸高的通道，并安装了从拱柱到山脊的2x4（换句话说，垂直于山脊）。

你需要底通风口等a ridge vent. You also need (ideally) roof sheathing that is relatively vapor-permeable -- meaning that board sheathing or plywood is preferable to OSB -- and roofing underlament that is relatively vapor-permeable (for example, #15 asphalt felt or one of the vapor-permeable synthetic underlayments).
lance_p|2018年4月17日下午2:18|＃12

Good to know, thanks Martin. I was only familiar with that particular article as I'd just read it recently.

关于一般墙壁问题的解决方案。我一直在考虑最后一天左右的问题，并想知道与替代选项（即巴特绝缘材料）相比，严重程度是多少。如果我们认为巴特绝缘材料从一开始就从来没有真正填充过腔和吹动，我想知道在纤维素降解之前，需要用纤维素降解多少（墙壁顶部的间隙）巴特？
GBA Editor

马丁·霍拉迪（Martin Holladay）|Apr 17, 2018 02:31pm|＃13

槊，
If your walls are dense-packed by an experienced installer, there is no reason to worry about settling.

定居不是一个普遍的问题，几十年来一直没有。“纤维素可以解决”问题主要是由竞争对手绝缘材料制造商推广的红鲱鱼。
lance_p|Apr 17, 2018 09:33pm|＃14

Thanks Martin. After reading more than I can remember about cellulose I've come to that same basic conclusion. I'm still planning to use cellulose, the benefits sure seem to outweigh any potential drawbacks.