Comparing Two Wall Assemblies Based on Costs
你好，
I’m planning a renovation for a 110 year old house in Southern VT (zone 6). The house has cedar clapboards with board sheathing and no WBR. Exterior walls are 2X4 7/8″ studs and have never seen insulation.
I’m looking for advice on the relative costs (material & labor) for two potential wall assemblies for general comparison, plus any thoughts and feedback on these options in general.
In either scenario interior surfaces and windows will be replaced. We’d inspect for major water problems and fix them. Old window weight pockets will be foamed in. New windows to be <=U0.17 and don’t represent an outsized % of the wall area. We’d add flashing, etc. at the windows as feasible. 3 stories – 3rd floor under the rafters. Nice big overhangs at the eaves so we have some protection of the siding if we keep the exterior as is or room to add exterior continuous insulation if we go that route.
选项1 - 使用喷雾泡沫并避免重大外部工作
内部到内部：
保持现有的搭扣和护套。
在护套的背面安装凹痕式房屋包裹，钉在螺柱上，以进行一些水分管理/保险……也许可以帮助油漆保持。
2x2s furred to interior of studs horizontally to extend existing cavity depth to 6 3/8.
HDSF以填充腔体和1英寸的旧螺柱前，以进行热休息。泡沫深度为5 7/8英寸，其腔体的最后1/2英寸正如干墙后面假设的，因为它是HDSF。
没有其他蒸气屏障。
5/8英寸的干墙
我相信，这个总墙件组件（不包括窗户）最终会在R29（U 0.34）左右，并且将满足U0.45或更少的替代路径代码要求。（〜R14框架路径，〜R39绝缘路径，20％框架因子）。
优点：一种用于空气和蒸气控制的解决方案。避免使用外部绝缘层复杂。保留历史性。
Cons: Higher risk of water issues. Paint retention may be a concern. Lead paint still there to deal with.
Option 2 – No-spray foam route with exterior insulation
Replace the clapboards and trim, freeze boards, etc. and add exterior CI and proper WRB/AIR barrier, flashing, etc.
内部到内部：
New fiber cement or cedar clapboards
3/4″ rain-screen gap / furring
3″ of Rockwool comfortboard 80 OR recycled EPS
WBR（亨利·布鲁斯金）
Existing sheathing
现有的4 7/8英寸腔中的致密计划 /喷雾纤维素。
Vapor retarder? – maybe smart membrane, maybe just paint the drywall and call it good? (Seems like I can use a class III VR since the mix of interior and exterior CI should provide the right hygrothermal management and this assemble can dry both ways)
5/8英寸的干墙
也许…我们也使用aerobarrier之前填补the cavities to improve the air barrier vs. relying only on the blueskin with an old structure and tricky details at transition points.
我认为总墙件组件（不包括窗户）最终左右左右R24或25（〜U 0.4），并且将满足U0.45或更少的替代路径代码要求。（R17〜18框架路径，R27〜28绝缘路径）。
What do you think of these options?
您能否建议来源我可以在其中找到每个平方英尺安装成本的信息？
Thanks!
斯科特
GBA细节库
由气候和房屋部分组织的一千个建筑细节的集合
答复
斯科特，
If you haven't already, be sure to check out this article on deep energy retrofits (//m.etiketa4.com/article/a-practical-look-at-deep-energy-retrofits）。
Thanks Steve. I'll check it out.
嗨，斯科特，
这是一个很棒的房子和项目。这使我想起了哈德逊河谷保存的一位梅森勋爵：Deep-Energy Retrofit of an Old Timber Frame, Part Oneand旧木材框架的深度能源改造，第二部分. The house is in Washington Depot, CT, zone 5. Mason could be a great contact for you. I imagine he could certainly talk costs.
Kiley，谢谢。我感谢这些信息。
这是很多壁板。如果您还需要更换壁板，那么任何外部绝缘工作的唯一方法是值得的。如果壁板的形状不错，则仅内部是较低的成本选择。
您的选项1听起来好像您的大多数东西都很好。我建议一些调整。去寻找具有真正厚度的可排水WRB，例如Slicker HP，以具有不错的气隙。更多总是更好，将1x1固定在角落，并在其之间伸展标准的房屋包裹会更好，但劳动更多。
There is no need for closed cell foam in your walls. Instead of cross strapping, I would go for foam strips like this:
https://www.finehomebuilding.com/project-guides/insulation/breaking-the-thermal-bridge
Instead of foam+1x3, simpler option is to rip R9 ZipR and nail that to your studs. The foam strip + oc SPF in the cavity would get you close to an R22 assembly (VS R26 ccSPF) but would allow for moisture to move through the wall, use significantly less polymer and be much cheaper.
With half story construction and dormers your roof is complicated, I think the simplest there is closed cell foam against the roof deck. Make sure to carry the SPF down all the way to your wall top plates for air barrier continuity.
Akos, Thanks! Love the idea of extending the cavities with strips of ZipR on the studs. Great suggestion.
我同意您对屋顶SPF的想法。我处于50〜60 psf雪地，但是我们需要一个冷屋顶，否则我们可能会遇到冰坝麻烦。三楼的居住空间直接在the子下方。我们对屋顶的想法是使拱腹通道用令人振奋的挡板般的山脊通道，以使我们在屋顶下方的气流〜1.5英寸，延伸腔体，并填充它们。房间通过扩展腔体，但这没什么大不了的。细节如何围绕座舱工作，以及我们是否可以在屋顶下有效地通风，一旦我们打开墙壁，我们需要弄清楚某些东西天花板可以很好地了解正在发生的事情。