Cut-and-Cobble with Polyiso and Spray Foam to Insulate a Vented Crawlspace
对于我们在气候下的人来说，例如温暖的沙漠（在那里有通风的爬行空间起作用），这是否是使用最少的Polyiso和喷雾泡沫在地下下方创建密封和绝缘室的好方法？附件图传达了大部分想法。我超大了1/4英寸的间隙，使它们容易看到。通过上间隙喷洒泡沫几乎可以填补那个小的三角形空间。较低的间隙将使泡沫形成厚实的K形，其中两块Polyiso相遇。将切割每块倾斜的polyiso，以贴合地板I咖啡师的网络，并带有凹口，以允许更宽的法兰，然后喷洒泡沫和/或泡沫将密封多丽莎和I-咖啡师之间的交叉点。
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I intended this idea more as a contribution than as a question, but if it won't work for some reason, that would be good for me and anyone else who reads it to know.
Jeff, it's a clever idea, and might work fine. In general it's best to avoid interstitial spaces--ones that are not clearly "indoors" or "outdoors," as that's where bad things (i.e., condensation) often happen. A desert climate is pretty forgiving, but if you were in an area with humidity, you could find that air conditioning or heating leaves surfaces below the dewpoint, allowing moisture to accumulate. Another concern is that "cut-and-cobble," a term I believe Martin Holladay coined, may not maintain a good air seal long-term; monolithic spray foam is more reliable, and tapes and membranes are even more reliable. But in a forgiving climate like yours, this may be an effective approach.
Thank you, Michael.
Yes, we desert dwellers are fortunate to be able to leave most of the crawlspace unconditioned, including the little triangle formed by the rim joist, top of stem wall, and hypotenuse of polyiso in the design I proposed. The ground here is teeming with termites, who apparently aren't inclined to build tubes up concrete stem walls, and if they ever did, the tubes would be visible on the bare concrete. Encapsulation of the crawlspace walls would protect and hide them if they ventured upward, not to mention that it would increase, in my case, the amount of space I'd have to heat and cool by roughly 33%. I considered no crawlspace at all, which would have eliminated a huge amount of work, but a slab would put my wood within easy and largely unseen reach of the termites, and the typical solution, poison, was unacceptable on general environmental principles magnified by getting my water from a well less than 60 feet away. A basement would have been beyond my budget. The only other option seemed to be woodless exterior walls, but at the time I had to decide, I couldn't find a source of the kind of blocks I might have wanted that was close enough to keep the shipping affordable.
在我看来，在地下地板上绝缘的Polyiso周围有空气泄漏的地方最有危险的地方，是地板托梁上的Polyiso板，遇到了RIM托梁区域周围绝缘的任何东西。随着Polyiso本身的边缘将其紧紧地钉在托梁上并贴上胶带，泄漏似乎不太可能，但是如果他们用来用来靠在边缘托梁周围隔离的泡沫泡沫，甚至会出现随机间隙，甚至会出现随机间隙如果将泡沫切开以使其笔直，因此需要一个小的故意缝隙来涂抹更多泡沫以确保密封。通过将水平的polyiso屁股与倾斜的碎片保持更加经济和浪费更少，整体上使用较少的泡沫，而在两块polyiso之间密封的泡沫的K形应保持不变，而不必依赖于粘附。在轮辋托梁区域使用polyiso的另一种方法，将其连接到轮托梁，窗台板和茎壁的顶部，将使用更多的polyiso和泡沫，从窗台的内边缘向下走向茎墙顶部的裸露部分将是一个更挑剔的细节。
>"Encapsulation of the crawlspace walls would protect and hide them if they ventured upward, not to mention that it would increase, in my case, the amount of space I'd have to heat and cool by roughly 33%."
Cooling & heating loads don't increase by volume. The loads are somewhat affected by sun-exposed above grade stemwall which can be insulated- usually with less foam than what is being proposed under the floor joists.
In much of the desert SW of the US the subsoil temperatures are between 65F and 75F, optimal for "earth coupling" the house to an uninsulated crawlspace floor. Insulating under the joists isolates the house from that potentially beneficial moderate temperature thermal mass which increases the cooling load, and possibly the heating load too.
这张地图对于设计工作太粗糙了（您的县可能有更详细的良好温度图），但它使您可以了解它可能工作的地方：
https://www.builditsolor.com/projects/cooling/us-grouns-temps.gif
But measuring the temperature of the water in your well would be even more precise, eh? :-) Even at 60F subsoil temps it's worth considering earth-coupling.
在白蚁区域中，在茎墙的爬行空间露出部分上安装刚性泡沫是可以的，留下了〜3英寸的裸浆果检查条。切割可移动的岩石羊毛巴特的切条以填充检查条，使隔热条连续进行（在定期检查期间除外）每年通常很好）。
Very interesting, Dana; thank you.
当你说,“冷却和加热负载不t increase by volume," I assume that depends on keeping the surface area of the conditioned space constant. If I add the exposed crawlspace walls to the conditioned space, they'll lose and gain heat, more so if I don't insulate them at R-30 like my wooden double walls, but I would be trading a floor that has to be insulated for one that's earth-coupled, so figuring out the net effect is complicated.
我找不到任何土壤温度数据，但在您引用的地图上，我非常接近57度线。我认为一个未绝缘的平板具有与爬网空间的一部分相似的热效应。当我使用LoadCalc.net和YourVirtualHVAC.com（现为EDS.Tech）进行排气爬网空间和绝缘地板进行加热和冷却负荷计算时，两者都显示我的加热负载约为12,000 BTU，而我的冷却量则在6800左右。我用无隔离的平板进行了相同的计算，加热约为18,000，冷却6600。我刚刚回到那些计算器，尝试一个无通风的绝缘爬网空间，以查看与平板有多大的不同，也许是因为它在边缘周围暴露了，但是LoadCalc.net奇怪地缺少一个未通风的爬网空间（除非我缺少一些东西），另一个网站不再提供相同的免费工具。您认为在热耦合方面，爬网空间地板有多少不同？如果在R30处有木墙，则应将爬网墙隔热多少？