更多能量智能细节
节能改造总是充满挑战。他们是a delicate balance between what to keep, what to eliminate, and what to add. That’s what we were facing on this recent project. The existing structure had 2×4 walls 16 in. o.c. and a turn-down concrete slab foundation. We stripped the building down to the studs by removing the exterior fiber-board sheathing and interior gypsum board. With naked 2×4 walls and an exposed slab, we started the retrofit.
The first step was to insulate the slab, which was positioned significantly above exterior grade. We spec’d 2-in.多异尿素刚性刚性绝缘. Because the existing slab is coupled to the ground temperature, which is most likely cooler than the desired conditioned temperature of the living space, there is a constant thermal drive for the room to attempt to warm the ground below. The polyiso provides resistance to that thermal drive.
The continuous nature of the polyiso insulation nearly eliminates thermal bridging across the floor assembly. (Note that the level of insulation here is appropriate for a moderate climate. For colder climates, 4 to 5 in. of rigid foam would be advisable.) On top of the 2 in. of rigid insulation, we added two layers of 3/4-in. Advantech floor sheathing. The second layer was laid perpendicular to the first layer with the joints offset by 2 ft., and the two layers were glued and screwed together to form a 1-1/2-in. “floating floor” assembly. (The Advantech allows for any type of finished flooring—hardwood, tile, carpet, etc.)
在墙上，我们添加了新的7/16英寸。拉链护套到外部框架上。所有关节都被清洗，胶带和卷。拉链是主要的空气屏障。我们安装了2英寸的舷外。箔面的聚异氰透明式刚性绝缘材料，我们施加了1×3木毛圈条，以使壁板远离…
16条评论
Any thoughts on the trade off between adding the insulation over the slab vs continuing it down the edge of the slab?
Continuing it down the edge of the slab doesn't solve for heat loss to the ground.
This looks like a good solution all around and I really appreciate the level of detail provided. I'm curious about two things.
One question is the 2x4 blocking at the base of the drywall. It seems like that would add some minor thermal bridging at a corner that is a bit of a thermal weak point anyway, and I'm not sure what function it serves. Is it to anchor netting for blowing in cellulose? Or to facilitate detailing the drywall as a secondary air barrier?
我的另一个问题是,我觉得有些人avoid polyiso in direct contact with a slab for fear of moisture wicking into it. Is that more of a concern in a basement and less of a concern with a slab that is at or above grade? Or is it a case-by-case decision based on whether it seems like there have been moisture problems in the past?
石膏板底部的阻塞仅在那里，因为建筑商希望它用于底板附件。
至于多丽莎
Alexandra,
A question recently came up ab0ut rain-screens in the comment section of your last blog. Do you worry much about venting the top of rain-screen cavities?
昨天我刚刚制定了类似的细节，以使现有的独立车库转换为ADU。现有的路缘和2x4壁组件，并保留灰泥。我能够将地板组件放在足够的地板上以覆盖路边。
因为在XPS泡沫绝缘之前，我在先前的车库开口上的平板斜坡上倾斜，所以我在混凝土上包括了一个自动化化合物以及蒸气屏障。
Interested in any feedback.
Your detail has a lot more thermal bridging than at the corner than the one in the article, through concrete which is much more conductive than wood. The results will be cold baseboards, increased heating energy consumption, and possible mold problems in those corners. Raising the floor more, similar to what's in the article would be the best solution, but if you can't do that, some exterior insulation would help.
Also, conventional Foamular XPS has huge climate impact, way beyond the other materials that people worry about when they get into worrying about embodied carbon. If you must use XPS, Owens-Corning now has an "NGX" version with only 10% of the impact of their conventional one and that can be special ordered anywhere in North America. Graphite-loaded EPS or polyiso are even better, but no matter what, don't specify conventional XPS.
Hey Charlie, thanks for the input. Just saw this now.... Agree with all you've said. Thanks!
“（Advantech允许任何类型的成品地板 - hardwood，瓷砖，地毯等。OSB现在被批准了吗？
我正在改装现有的平板，看起来整体状态良好。我应该担心使用自我平整器还是不关心？
"To deal with the exposed edge of rigid insulation, we applied a 2x continuous treated wood block." Why can't the edge be exposed?
查尔斯，
为了防止损坏机械保护，并阻止害虫获得通道。
它还为底座上的通风孔提供了后备，并从水平表面开始了外部绝缘层和雨屏毛茸茸。
您是否卸下了以前的外墙护套，或者这所房子除壁板外没有任何护套？如果尚未有壁板，您是否考虑使用Zip-R护套而不是外部Polyiso？
Regarding raising the floor with insulation and Advantech, did any windows now become close enough to the floor causing you to have to replace glass with tempered glass? I presume this may be more of an issue in colder climates where the insulation would be thicker. I forget if it's 18" or 24" from the floor.
谢谢你。
In a colder climate, would you be concerned about frost penetrating under the slab and causing it to heave?
一些有关您的集会的问题以及一些可能的修改以满足我的需求。我也有类似的墙集会，但我处于一个高架基础上：
- If I applied a WARB and spray foamed from crawl space with closed-cell foam and then did Aerobarrier from the interior to the existing flooring (T&G boards) could I get an improvement in airtightness that is comparable to replacing the subfloor with Advantech or some other subfloor?
- Regarding the wall exterior sheathing - what kind of disadvantage is there to keeping existing sheathing (uncertain on type - could be T&G or plywood sheets), applying a fluid applied WARB, and doing Aerobarrier? Will this setup help cover the airtightness effectiveness gap, if any, relative to replacing the exterior sheathing completely?
上面的想法是减少我从项目中产生的浪费 - 假设现有的地板和外部护套状况良好，我的想法是，我继续使用现有的和使用现有的系统来改进这些系统，而不是生成太多。从基本上好的材料中浪费。这个想法有缺陷吗？
A few more questions:
- For the rain screening, how do you do ventilation at the top for the air gap on such a retrofit?
- What is the function of the acoustic sealant? is it only on the bottom sill or also the vertical 2*4s?
- Can you use 2” Rockwook instead of the poly-iso?
- You show the 5” screw to secure the furring through everything into the framing, but none are shown for the insulation - what are you specifying for this? Does it go directly into framing or is supported by the sheathing?
- 您显示1*3条毛茸茸的条而不是1*2条毛茸茸的条 - 是否有较大条带有任何性能优势，还是为了更轻松地安装？
Thanks for the article Alexandra. I found it when I was searching for an answer to my question regarding top of slab insulation in a remodel in Taos NM (Zone 5B).
我想我会转向蜂巢的头脑，以帮助我尝试解决这个问题。
I am using BEOpt V2.8.0.0 to model a semi deep energy retrofit of a home my wife and I recently purchased. I was quite shocked to find when I added insulation to the top of the slab that it dramatically increased my loads not met (Hrs/year) with the same sized equipment (24,000Btuh minisplit for a single story 1200sf house). BEOpt doesn’t have a way to add “insulation” to the top of the slab so I used the Foundation Floors>Carpet input which allows you to specify the R-value of the carpet pad.
In the attached graph:
点1是一个没有绝缘的平板
点2是平板R-10绝缘的100％顶部
点3是平板R-20绝缘的100％顶部
Point 4 is 4ft R-20 vertical insulation on the exterior of the slab (no top of slab insulation)
Point 5 is 4ft R-20 vertical insulation on the exterior of the slab and 100% top of slab R-10 insulation
点6是平板外部的4英尺R-20垂直绝缘材料，平板R-20绝缘的100％顶部
I assume the increased loads not met have something to do with de-coupling the slab (thermal mass) from the interior space but I’d love for someone to give me a sanity check that I am modeling this correctly and, if so, does it make sense to insulate the top of the slab at all?
Is using the carpet input as a way to model top of slab insulation a reasonable approach?
I ran a second case with just 40% top of slab insulation (approximately the same area that would be covered by 4ft of insulation around the inside perimeter of the house. While the model doesn’t know what the exact location of this insulation is the Loads Not Met numbers were lower but still significant and followed the same pattern of the higher the R-value of the top of slab insulation the higher the Loads Not Met hours.
对这里发生的事情的任何洞察力都将不胜感激！！！
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