Dense pack insulation below grade
我一直在看混凝土sip。我一直在寻找的地方暗示了每侧有2 1/2英寸混凝土的外壳，内部为7英寸XPS。
Okay, this sounds good. You get high thermal mass on the inside and the exterior shell protects the xps from bugs, etc.
But is there a way to make it better(cheaper)? Could it work 2 sheets of xps up against the concrete walls, but then fill the space between the walls with dense pack cellulose (3 inches or maybe even increase it to 5 inches)?
我很紧张，因为如果水进入壳相对不透水，因此水将无法下车。你好模具！我会尽力而为就是可以考虑使用空气夹带和混凝土添加剂防水。XPS的外壳也将提供水分屏障，我可以看到这可能是一个低于低级外壳的坏主意，但也许不是上述级外壳？
Lets make this question more complex (convoluted) by asking if it might be okay if I used rock wool. I understand rockwool does not sustain mildew.
To make this post even more complex, if I made the rockwool dense would this help or hurt the insulation value? I understand (I think) that dense pack insulation has a higher R value, but would this be true of rock wool as well?
Thanks for any advice. I am still a couple years from starting my project but want to learn as much as I can.
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Bob
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答复
Robert,
You have a lot of questions. I'll start with the question implied by your title. The answer is, No, you don't want to use dense-packed cellulose insulation below grade.
Robert,
The wall you describe sounds like a variation on the Thermomass system. I would question the integrity of these thin shells of concrete though, and whether they could work together structurally with such a thick insulation layer at the center. Using cellulose in this type of wall would be a big mistake. XPS is a material to avoid because of its very high global warming potential. Rockwool might work though, and if you're interested in the relationship between density and R-value just look to manufacturer specs (see Roxul and Thermafiber). The highest R-value is at roughly 3-6 PCF density.
You could build a double wythe masonry wall using 4" block or brick and rockwool at the center (say 8" thick to keep the module), with ladder type steel reinforcement. That would be thicker than what you describe but more conventional as a construction method. This wall would have incredible sound transmission specs.
感谢Martin和Thomas的回应。马丁习惯于听到我不断的毛发问题。你们俩都证实了我的想法，即低于年级的纤维素可能是个坏主意，但我想听听专家的想法。
Thomas, I have taken my ideas from the following sites but my proposed modifications were my own. The two major sites I looked at were:
http://www.sipcrete.com/index.htm
http://www.solarcrete.com/insulated-concrete-wall.php
Neither of them proposed the thickness or substitutions which I was considering. Solar Crete does propose a 12 inch wall with a 7 inch core of EPS surrounded by 2 1/2 walls on each side. Please note how they use ties to hold both thin walls together and make the whole serve as one structurally strong wall.
I did like you suggestion about a double wall with rockwool in the center. The major problem with that kind of wall is that it probably precludes using surface bonding as advocated by thenaturalhome.com
我喜欢表面粘结，因为它似乎比传统梅森这样做的技巧要少得多。
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Thanks again for your good ideas.
Bob
PS: Thomas, are the problems you mentioned with xps also there with polyso (above grade) and eps? I thought they had reformulated the gases used to make them less of a problem.