在4区喷雾泡沫和减湿问题
I am remodeling a home outside of Seattle, WA. I plan on spray foaming the existing 2×4 exterior walls with closed cell spray foam (looking for R-24) and plan to frame out a new interior wall (probably 2×3).
我想在现有的外墙和新内墙之间的缝隙中安装一个2英寸的聚异透明板，以在我的外部墙螺柱的脸上添加连续的R-13。聚异氰尿素将被填充到螺柱上，彼此，关节将被粘贴。
我担心墙壁内部收集水分。关于管理进入墙内内部的水分的任何技巧或建议吗？我渴望使自己的家用空气紧密，隔热，杀死附近繁忙的街道，并避免在墙内种植一个漂亮的模具农场。
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马修，
如果您在螺柱托架中安装闭孔喷雾泡沫，以及在螺柱内部连续的polyiso层，只要您拥有良好的外部闪光和水管理细节，墙壁护套和螺柱可能会保持干燥。这种类型的壁只能干燥到外部，因此它将受益于通风的降雨间隙。
That said, there are lots of ways to build a wall. It sounds like you want to build a double-stud wall -- is that correct? Were you planning to insulate between the studs of the new 2x3 wall? Most double-stud walls are insulated with dense-packed cellulose, not spray foam. (Many green builders try to limit their use of closed-cell spray foam because most brands of closed-cell spray foam use a blowing agent with a high global warming potential.)
For more information, seeHow to Design a Wall。
Closed cell foam installed in 2x4 framing 16" o.c. is a waste of good foam (at a high envrionmental & financial cost), due to the thermal bridging of the 25% frmaing fraction. Even though you would have a center-cavity R north of 20, after factoring in the thermal bridging it only adds about R1 to the "whole wall-R" perforamance beyond the same wall with ~R13 half-pound density open cell foam that uses 1/4 the polymer, and water as the blowing agent instead of climate-damaging HFC245fa (with a global warming potential of about 1000x CO2).
仅在0.5磅的泡沫腔填充上，将仅1/4英寸添加1/4英寸，将超过2磅泡沫的性能增长，并在较大的环境击中。使用1磅polyiso（而不是1.5-2磅的屋顶polyiso）使用一半的聚合物每R的2磅闭合细胞泡沫，并用戊烷吹，其GWP约为7倍CO2。
With 2" polyiso (all facer types) in the middle of the assembly, the exterior studs & sheathing will have to dry toward the exterior, and the interior needs to dry toward the interior. The interiror studs will not have an issue- there is PLENTY of exterior R for keeping those materials above the ~45F interior air dew point in that climate. But the siding type , roof overhangs, and flashing details will determine how dry the structural sheathing remains.
在美国气候4的位置，可以使用PV阵列以大约R20-R25的全壁表演在房屋上击中净零能量。请参阅本文档的表2，第10页：
https://buildingscience.com/sites/default/files/migrate/pdf/ba-1005_high%20r-value_walls_walls_case_study.pdf
在2010年，当它写得更好的无管热泵时，HSPF的HSPF约为10-13-13，而高输出光伏太阳能（PV）的效率约为15％，现在运行量约为20％。屋顶光伏的价格也约为2-2.5倍。2016年的价格。典型的2x4/R13墙，具有典型的壁板和室内装饰选项的全壁约为R10。即使没有内部螺柱，添加连续的R13（Polyiso的2英寸）即使在R20的北部也使其在R20中的北部。在某个时候，与安装屋顶PV（甚至在西雅图脱落的西雅图）或将钱投入其他物品（例如基础隔热等）相比，它不再具有财务意义表2.该文件的墙壁而不是越来越多的墙。在那个索赔中，我自己的倾斜度将是2x4s和2“ polyiso的开放式细胞泡沫（或3磅+密度纤维素），将石膏直接粘合并长期拧紧到Polyiso，跳过室内螺柱。
在许多地方，有二手屋面多丽莎的供应商（通常是2磅密度，r5.5/英寸），占原始库存商品的一小部分。在我的地区，在您所在地区的2英寸厚屋顶ISO的2英寸厚屋顶ISO的回收4x8张（显然在您所在的地区也大约相同的每平方英尺）：https://seattle.craigslist.org/sno/mat/5937828295.html) Reclaimed/reused foam (any type) is by far greener than any virgin stock, since the environmental hit has already been taken, and re-using it is just piling on to the benefit side of the cost-benefit equation.