寒冷气候地下室嵌入式托梁的内部绝缘
我打算在地下室安装一些绝缘材料时触发，直到我读到绝缘嵌入式边缘托梁的“问题”，并看到了很多相互矛盾的信息。
First, I live in SE Wisconsin (Climate Zone 6) and have a 1930s house with cinder block basement walls, concrete floors, embedded rim joists, no HVAC sources in the basement, and likely no exterior insulation or waterproofing. Basement is almost entirely below grade (even the joists are mostly at or below grade).
我的目标是在地下室周围添加石膏墙墙壁，以及一些天花板，以使事物变亮，但并不希望使其成为完全完成的区域，或者必须寻求满足其代码要求。
我的计划是/只是在地下室周围的墙壁上简单地安装2英寸的XPS刚性绝缘材料，然后将2×4螺柱墙壁带有1/2英寸的干墙，没有隔离板，并且在腔室中没有绝缘材料这是一个完成的空间）。我了解，绝缘水平足以为螺柱和干墙提供防水侵入的保护，并且足够浓密，以避免使用较薄的XPS绝缘材料带来较低的R值。
然后我开始阅读有关嵌入式托梁的阅读（这是我的照片：https://bit.ly/38bOHyD）。托梁似乎搁在煤渣块墙的顶部，然后混凝土或某种类型的砌体在托梁之间一直紧密地填充到顶部，并且该垂直表面齐平，下面的煤渣块墙面表面齐平。托梁没有显示出任何先前水损坏或腐烂的视觉迹象。
I had thought I was going to run the 2″ XPS wall insulation up into this joist space and seal the XPS around the joists and floor, but then started reading about concerns with this causing the joists to rot. I’ve read some different things about what to do here, such as max 1″ XPS insulation (per Canada’s energy website). Some say don’t do it at all. Some say add insulation, but leave a gap between it and the joists.
I’d like to know what the realistic options are here for interior insulation that are least likely to moisture or rotting issues. Not looking to insulate the exterior, cut off joist ends, etc. Again, I’m looking more to protect the studs and drywall walls I’m building from moisture than to provide energy efficiency. Above all, I want to avoid doing anything that could create moisture/mold/rotting issues.
1) Are there any risks if I install the 2″ XPS from the floor to the bottom of the joists and put no insulation in the joist space?
2) Are there any risks if I install the 2″ XPS from the floor to the bottom of the joists and install 1″ XPS in the joist space? If so, should I airseal the XPS around the joists and subfloor? Or leave air gaps between the joists and XPS? I’ve read both ways….
3) Are there any risks if I do same as (2) but with 2″ XPS in the joist space?
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Just to confirm, you have some joists ends that are below grade, and all the joists are embedded? I’ll give your post to see what the experts advise.
That’s right, the grade is essentially near the top of the joists. It’s a city lot and the grade is pretty much level from the house to the adjacent sidewalks; there’s not much that can be done with it. While the whole setup is probably not ideal on paper, it has seemingly lasted 85 years without issue.
All joists are embedded that way on the east and west sides where they terminate into the walls, minus a few that have openings for radiant heat pipes and water pipes for exterior hose spigots. The north and south walls run parallel to the joists but there is also masonry built above the cinder blocks all the way up to the subfloors on those walls.
I'm a non-expert, so YMMV with my input. It seems risky to do anything with the basement if you are unwilling or unable to build new bearing walls and cut off the ends of the embedded joists. I suspect the joists have not rotted over the last 85 years because your leaky old house has enough air infiltration to dry out most of the moisture that is trying to move into the ends of the joists. While wanting to tighten up the house is commendable, you may reduce that drying potential and increase the chance that the entire home will end up in the basement.
Let's see if any of the experts feel differently.
该地区的大多数房屋都有这种嵌入式托梁结构，许多房屋都有较新的地下室，而且我可以肯定没有人切断横梁端，并更改整个房屋的结构，以增加地下室娱乐室或工作室。我也没有听说过任何房屋正在崩溃，这似乎有些警报。我仍然理解这一问题，并试图为此找出一个实用的，具有成本效益的解决方案。如果这意味着托梁空间没有完全绝缘，那就这样吧。正如我提到的那样，我使用刚性泡沫的目标更是一种水分屏障，而不是提供温暖。
Given that, I'm mostly curious about whether it would be better to leave the joist spaces free of insulation or go the 1" insulation route suggested by Canada's energy agency (although I still have questions about the finer details of doing so and whether to air seal).
在阅读了有关此内容的几乎所有内容之后，任何专家是否对是否最好放开托梁空间没有隔热效果有意见？还是我会在托梁空间中使用1英寸的刚性隔热材料来表现更好，这是加拿大能源机构在托梁周围的空中密封的建议？地下室的两侧与墙壁平行的情况如何？
也许您阅读了此讨论：//m.etiketa4.com/question/what-to-do-when-the-ends-of-the-floor-joists-are-embedded-in-concrete. It outlines the pros and cons of different approaches in some detail.
I'm not sure any of the experts will venture an opinion that supports the plan you want to use. It may be that there is little risk of catastrophic failure, but that doesn't mean there is zero risk. My concern would be what happens 20 or 30 years down the road. In your case, the piled up soils on the outside of the home are probably keeping the ends of the joists warm and air leakage and stack effect are keeping moisture from accumulating in those structural elements. But what happens when you add insulation, conditioned air, and people into that spaces?
If you decide to move forward, I would install a few humidity sensors near the exterior and monitor things (using current conditions as your baseline).
I think you are safer leaving insulation out of that area, maybe even ending it 6" below the joists.
When you go to buy insulation, make sure you get the new "NGX" version of Owens Corning XPS foam that has low global warming potential, 1/10th that of their old stuff. Or use a different type of foam--EPS, GPS, or polyiso--that doesnt' have that problem.
You could insulate that area from the outside, perhaps with mineral wool board, to keep that part even warmer and lower risk more. If you aren't fully insulating on the exterior it's a lot easier than if you are going down 6'.
Thank you, that's what I might be leaning to. I guess I’m a bit confused how having the very top of the insulation touch the bottom of the joists would materially change how they dry out. But if it’s safer to keep them not touching, I can add some space. Would it still be a good idea to caulk around the joists to seal any gaps? Or are those gaps beneficial for drying?
您如何保护矿物羊毛免受天气和昆虫的侵害？我不是因为担心白蚁和蚂蚁而使用外部绝缘
至少看起来蚂蚁,可能和白蚁, either don't like or can't chew through mineral wool boards. We protected ours with stuccoed concrete backer board. That worked well where we back filed with good soil; where we made the mistake of back filling with clay, frost heaving cracked the backer board. There could be concerns about the board wicking moisture up from wet soil, so it's best where the soil is well drained.
嘿，
I have a similar situation. (Link to my post below).
我决定要做的是在轮辋托梁上喷泡沫1'，然后用硼酸杆杆注入任何可疑托梁。杆很大程度上是为了安心。我的边缘托梁嵌入了砖块中，比您的坡度高一点，但也许这种方法对您有用。
In response to my question, Khoa Ueno links to some good resources and seems to endorse the idea of borate as a reasonable, not too extreme solution. Maybe you’ve read the links, but I found them useful enough to read a few times.
Good luck!
//m.etiketa4.com/question/embedded-joists-in-cold-cold-climate-brick-basement-bassement-sunsulate-heat-heat-heat-heat-heat-heat-heat-heat-heaterate
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Thank you! Is there any reason to do spray foam in the joist space versus something like 1" of rigid foam? And I assume you are air sealing tightly against the joists then? Do you have rigid foam underneath the joists down to the floor?
I’m using spray foam in the joist space only because the brick and mortar there is so uneven it makes installing rigid foam impractical if not impossible. I have a few other areas in the basement that are like that so it just made sense to buy a spray foam kit and not drive myself nuts trying to cut and patch a bunch of rough areas with rigid foam.
The rest of the walls below the joists are a lot smoother, so yeah, those areas are rigid foam. I used 2” of EPS, foamed and taped at the seams.
我的家中的1堵墙也有类似的情况。我也想知道为什么您不能将刚性的泡沫放在托梁上并留下。托梁将自由干燥，值得牺牲的热量损失
Hey,
If I understand the literature correctly, the issue is that you risk condensation in the cavities. The 1” of foam is working as an air barrier, which is almost more important than the insulating value, though you lose a lot of r-value as well.
“消除边缘托梁区域的绝缘材料导致温度接近原始条件。然而，静态热模拟表明，基于横梁袖珍表面温度相对于室内露点，在典型的内部湿度条件下，腔内可能存在冬季凝结的巨大风险。此外，该措施丢失了完全绝缘病的能源节省的很大一部分（大约是R-14到R-7的热量损失的两倍）。”
https://www.buildingscience.com/sites/default/files/migrate/pdf/cp-1201_masonry_wall_wall_interior_interior_insulation_retrofit_embed_embed_embed_beam_beam_simulations.pdf
当然，我只是一名发烧友，也不是一位新手，所以希望拥有更多专业知识的人可以在这里体重，哈。
I thought that you didn't want an air barrier though to avoid the potential rotting and moisture issues? Isn't the theory that the joists and masonry or concrete infill between the joists should be exposed to warm air to allow for drying to occur?