如何将钢梁悬臂隔离到外部？
I am building a home with a large amount of steel beam cantilevers to the outside of the structure. I am worried about thermal bridges to the inside of the home, condensation, etc.
Directly against the web of the beam would be placed the sheathing, and then the siding (stucco). Directly below the flange would be a stucco board and then stucco.
由于网络和法兰都在外部旁边, what is the best method of insulating? I was thinking of filing the web with rigid, foam, or wool, and then applying a Dow insulated sheathing (R-3 to R-5).
As for the flange, the only thing I could think of is using a 1/2″ thick foam insulating board, with a wire lath and then applying the stucco. That would maybe give it a R-2.5 below the flange. On the other side of the web we are stuffing the wood TGI’s. So likely it won’t be insulated or I could spray an 1″ of foam in there.
Recommendations? Products? Anyone have any better ideas?
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I'm not sure exactly how this beam is being used but you call it a cantilever and say you are considering only 1/2" of insulation at the flanges. Assuming you are somewhere in the great cold north, this is not going to be enough to provide any help. In addition to the thermal bridging, which will be significant, the possibility of condensation will be high. Even worse is that it sounds like you are covering it all up so that when things start rotting, and the steel starts corroding, you won't know until it is too late and you have to tear it all down. Again, without knowing the details, I would look at using a wood beam instead of steel. LVL or PSL engineered beams may end up being deeper than steel, for the same span an loading, but have far less thermal transfer and are much easier to apply normal finishes to. They are also easier to push up into traditional framing which may get a major portion up into whatever the floor system is that you are using.
Brandon,
I would talk to your architect about changing your design. You don't want steel beam cantilevers penetrating your thermal envelope. Back to the drawing board.
i disagree with martin - you can penetrate the envelope w/ structural members (even steel) and still hit passivhaus, so a redesign isn't needed.
在欧洲和加拿大（关于热桥接问题，我们面前的Waaay）有一些产品 - 尽管通常是钢上的混凝土。
schoeck isokorb KST is designed for steel-steel connections through envelope. i think this may have even been used recently here in seattle but might be thinking of another product.
http://www.schoeck.co.uk/en_gb/new-construction/kst-36#category
images:
http://www.passivehouse-korea.com/assets/images/autogen/a_massnahme_isokorb_typ_kst1.jpg
http://www.dako-pr.de/uploads/media/10-01_Isokorb_KST_Detail_02.JPG
I saw these products on display at the International Passive House conference in Innsbruck last week. There are a myriad of applications that will provide a thermal break in steel beam construction. With planning and new product choices you can hang most anything you want, where you want, and design it to be thermally broken from the steel or concrete structure within the conditioned space.
You gotta love "thermal progress"!
我不确定我是否正确地可视化这种布置 - 光束是否完全位于正确绝缘的二楼平台下方，还是完全或部分嵌入其中？它们是外观的表达设计功能吗？显然，您不能在不破坏其结构目的的情况下“热打破”梁本身，但是如果设计参数不排除在内，则可以将光束包裹在外部上，以便它们有效地在建筑物的围栏内。做到这一点的最有效方法是将悬臂的地板擦到钢下方的完整深度，然后正确绝缘整个组件。但是，您似乎不会走这条路线。
只是包装和梁的底部you seem to be planning would be a rather poor substitute, though in Seattle's mild climate you could probably get away with it. But why not use at least an inch of foam board? I wouldn't recommend the Dow SIS for this application, the hardboard backer of the SIS is intended for wind bracing of a stick frame, would serve no purpose here. You just need a secure fixing for your wire lath - 2X furring behind the foam will do it. I agree with Mike you don't need a full redesign as Martin suggests, however it is pitiful that this issue was not considered and fully resolved at an early stage in the design process rather than subjected to a last-minute kludge during construction. Par for the course I know, but still, just pitiful.
好吧，您知道那些西雅图建筑师及其对钢制悬臂的事物！大悬臂是赢得奖项的最简单方法（作为部落的同伴说话...）。
I'm with the others, either wrapping in foam board, or coating the exposed steel in adhering spray foam and then casing the steel in stucco is your best bet.
在添加隔热材料之前，请确保通过信封的穿透性很好地进行空中密封，并希望使用柔性胶带可以承受随着时间的推移而承受差分热运动而不会松动的胶带。悬臂横梁是海洋气候下甲板和悬垂的经典泄漏点，并且非常棘手地将它们进入建筑物的位置。如果有机会，他们可以长距离水。
在该行业中，将建筑学美学和技术表现保持一致是一个巨大的问题，它们通常是强烈的。这是我们所有人都需要进行更改的事情。
解决方案是将钢的进一步exterior. It probably needs nearly as much insulation outside of it as all other parts of the house. If it's currently positioned right at the exterior surface of the building, it's going to be hard to insulate it.
This is the part that would really concern me. How is this going to be detailed so that the beams don't get wet and possibly even draw moisture into the building? I'm a little north of Seattle and stucco is a tough choice in this climate. You are probably going for a modern look. And, it's not arctic cold here, but people tend to use at least some heat about 8 months of the year.
Jesse,
Thanks. Your observation -- "Cantilevered beams are classic leak points on decks and overhangs in a marine climate, and very tricky to seal where they enter the building. They can wick water long distances if they get a chance" -- is one of the reasons I advised a redesign without the cantilevered steel beams. When I see beams like that, I cringe.
其他认为我反应过度的评论者可能有一点。可以将钢梁包裹在泡沫绝缘材料中并使其起作用。但是通常，这些细节是湿润的，没有足够的隔热材料和不良的空气密封 - 因此，值得一提的是，设计师像我这样的能量书呆子认为这些光束渗透到热信封中是一个可怕的想法。
The home is already being built. We were planning on just adding a thermal break below the flange of the beam (R-0.6). What if I tell them to fur all the ceilings down 2" and put in 2" of R-7 spray insulation or rigid board. Giving us a R-14 there. Plus then use the R-2.5 stucco board. Thus I would have about an R-14 to R16 below the flange of the beams (W14). Seattle code says R-29 on exterior walls and they would all be super insulated in between the joists except for the flange of the beams. Do you think this would give it enough of a thermal protection from the elements and keep the moisture at bay. Still the outside corners of the web of the beam would likely be an R-4 to R-6, but the inner side of the web would be about a R-20.
The steel beams are fully encased by the siding. They are not exposed to the exterior air at all. But are right up against the sheating and air barrier, etc. The steel beams are stuffed (with wood) and then TGI's are running in between them. The area will not be vented. Spray foam will be sprayed all around the joists to air seal the area. Although the spray foam is not directly sorrounding the steel beam. Will I have to worry about future rot of the stuffed lumber and joists. Because of the beams sweating / dew points / condensation because the flanges are so close to the exterior. Would it have been better to place a weatherproofing material fully around the steel beams before stuffing them?
They are wholly embeded below the second floor. Then subfloor placed directly on top of the top of the flange (beams stuffed). No water proofing planned above the top of the flange. Although I could ask the GC to add some layer of tarp or something below the subfloor (warmboard) to keep the moisture (if any exists) below the subfloor. I could also ask them to take out all the stuffing and apply some type of water proofing material (around each steel beam on all sides). They said spray foam sorrounding each steel beam would not be good as it would provide an uneven surface for filing the webs. recommendations?
Brandon, your most recent written descriptions create a very different impression than has seemed the case before. I think you'll need to post a drawn detail of the existing setup - and maybe some photographs - to clear up the confusion and then you'll be more likely to get a clear response to your concerns.
Here is a picture of the ongoing framing. You can see toward the back of the picture some of the beams webs are stuffed - wood directly against steel. Those beams cantilever the foundation walls.
Its a 3 story home. the second floor cantilevers over the first, the third cantilevers over the second. The steel beams support the cantilevers. The steel beams are not directly exposed to the elements but are very close (1" off or so). There will have to be R-29 insulation under the cantilevered floor between the joists. However, the flange part of the beam would maybe have just an R-2.5 sourading it. The home is being built in Seattle WA. So we have a mild marine climate.
Here are some sketchup photos of the home. The steel is embeded beneath the siding. Its just that the steel is very close to the exterior and the bottom of those flanges are not sorrounded by much other than the siding and maybe a R-3 beneath them. We will be doing our best to seal all air out of the underside of the cantilevers using spray foam, taping to make it a air-tight space. I'm just worried about those beams getting cold in the winter, reaching the dew point, sweating and rotting the stuffed beams on my house, TGI's, and subfloor (warmboard). Plus them bringing in cold to the structure and subfloor which is directly on top of them and raising my heating bills. The rot, if it happens, Its something that would never be covered under my warranty with the GC because it would likely be something I deal with 10+ years down the line. should I have a concern or have him make any changes so that the wood is not against the steel (wrap beams in visqueen before stuffing and putting the subfloor on top to keep moisture if it happens off the wood, etc) ideas. ? Or do you think I'm worried for nothing because the beams will be fully encassed under the siding in an air tight environment and the likely hood of problems is very small.
Thank you for all your help.
I see lots of "issues"
有些比其他人更令人恐惧。
Brandon,
感谢您提供的更多详细信息。现在，我看到您的光束问题与我可视化的问题不同。但是，您还有很多问题要解决。
设计师将热绝缘和空气密封的细节留在了这样的晚期之后，这是不合情理的 - 施工已经开始！我只是不明白建筑学校如何有可能毕业这些无知。
好一幅值得他们说,一千字nd this demonstrates the point very well. From a quick glance I'd hazard a guess that condensation on your cantilever beams might be the least of your problems ten years or so down the road. Yes, this amount of steel will create excellent thermal conduits to/from the interior of the building unless they're covered with the equivalent of at least a couple of inches of foam on all exterior surfaces: I don't see why this would be difficult to achieve though from what you say it doesn't seem to be in the contractor's current plans. With this much glazing you can't afford to cut corners on the thermal performance of the other parts of the building enclosure. But also watch for failed parapet flashings, clogged roof drains and all the other well-documented performance problems of 'white modernist' buildings in rainy climates. Your framing is far more likely to rot from liquid water penetration resulting from these kinds of failings than from any amount of condensation on the steel. Get the drawings reviewed by a competent third-party engineer before it's too late. This kind of building is not fault-tolerant. Unless you're careful it's going to be a very high-maintenance home.
Just to be clear...
我建议一名工程师查看物业线附近的挡土墙
I am not familiar with your soil... This does not look "safe" to me
I looks like the windows a level above the garage door and down the left side in the center rendering would interfere with insulating under the beams. If those can slide down you can insulate to your hearts content
don't order the glass yet............
是的，詹姆斯说的话，问你设计师是否知道平坦的屋顶不是真正平坦的。
我同意建筑学校有一些“不好的”
And the Profession
Brandon,
As Keith said, at the least, dropping the cantilevered soffit down 3 - 4" would allow a real layer of rigid foam to be added to the underside of steel, which would do wonders to isolate that steel from the exterior vertically. The rear of the house will have issues with the window hard up against that soffit (would have to shrink), but you could end up with a consistent window to soffit detail around the house front to back in the end with this revision if you raise the front windows in tandem with rear lowering.
Width issues are difficult to judge without a wall section, but 2" minimum rigid would be a starting point to the outside face of packed out steel.
布鲁克斯，你绝对是残酷的。我确定永远不要发布我的任何项目的照片！
PSHAW！
建筑学校不是问题。专业也不是。建筑师不到3％的单个家庭住宅。
but to respond to your "dwell" crits - i've seen all of those details successfully implemented on a passivhaus. granted - this house won't meet passivhaus - but you couldn't discern that from the rendering alone.
for example - your约翰·波特曼（颤抖）混凝土热桥很可能是一个valerio olgiati paspels schulew/ concrete sandwich wall w/ ample insulation and an incredibly awesome structural feat of hanging the outer leaf on massive shear studs... stunner! bonus points for the corbusian scupper!
http://www.pratval.ch/assets/images/Oberstufe%20Paspels.JPG
additionally, you need more glass here in the NW - it's absurdly difficult to dwell comfortably in your home without it. Even with high VT glass - "normal" windows just don't let in enough of our overly limited daylight.
btw, the kundig-designed corten beaut jesse posted @8 comes with some really cool rental facilities - the herd:
http://www.rollinghuts.com/the_herd.htm
David,
You are right
I will accept the "nice lesson"
I did not intend to insult the owner or the Architect.
From what I have seen .....
建筑学校和建筑媒体似乎荣耀了玻璃和钢
and drop the ball on Low Energy and Durability.
Mike,
You wrote, "Architecture schools aren't the problem. Neither is the profession. Architects are responsible for less than 3% of single family homes."
我当然同意，大多数住宅设计不涉及建筑师。但是我从来没有声称他们做到了。
1. I'll bet that an architect designed the house under discussion in this thread. If there is no architect on the project, I'll apologize for my slandering of architecture schools.
2. It appears to me to be a little late in the project for everyone on the job site to be scratching their heads and asking, "How do we insulate the exterior of all these steel beams?"
3. Such thermal bridges are sadly common on commercial buildings designed by architects, and I am not the first person to note the problem. Somehow, architecture schools are producing graduates who repeatedly ignore the fact that buildings need air barriers and thermal envelopes. This is astonishing to me.