Just getting started, first question about insulation
我昨晚重新发现了这个网站/论坛，在寻找一个解决方案的阵雨问题时，在这里发现了一个关于类似情况的问题。我需要注册，以便搜索那张海报，看看他是否找到了一个解决方案，发现我已经注册了。显然我几年前注册了几年前，也许当我需要寻找解决方案时。The poster either never found a solution to his problem, or didn’t post about it if he did, but I started reading some of the posts that did come up in my search and was surprised to see how similar our goals for our new build are with the green building goals. We have built traditional homes before, but we are in new territory now and have a lot of questions with few people to ask.
背景：我们正在建造一个谷仓家 - 一个焊接金属建筑。我知道这些都不受欢迎，但我们选择了这种方法有几个原因。只有时间才能判断是否是正确的选择。我们在潮湿，潮湿，德克萨斯州。
我们的建筑是一个矩形，坐落在崛起的顶部（不是真正的山坡，而不是平坦的土地）。风休息很小;春天和秋天非常刮风。长边面对北部和南部，拥有大部分窗户。除了两个南窗外，除了一个北窗户之外，所有南部窗户都在10英尺以下。门廊下的窗户也有百叶窗，可以关闭，以保护它们和内部空间。西侧有两个窗户，也有百叶窗，东侧有两个窗户，没有挂起，没有百叶窗，但面向东，他们不应该有问题。
Next to the living space is a drive through garage which will have screens so it can double as outdoor living/breezeway and will also have a mini kitchen to reduce cooking heat in the living space in the summer. The stairs are in the center of the living space with a cupola above it to pull heat out and hopefully reduce the need for as much air-conditioning. Air-conditioning is a big concern, but it’s not immediate so I’ll come back to that later.
The plan is to spray closed cell foam the inside of the entire metal building, 1 inch. The living space will be built with 2×4’s inside the metal building faced with solid foam core and set 2″ apart from the metal framework. We’ll use batt insulation between the 2×4 exterior walls and between first and second floor. Then sheetrock on walls, beadboard ceilings, hollowcore interior doors, insulated steel exterior doors. Windows are vinyl clad aluminum.
We have received so much conflicting information about insulation, mainly from the people giving us bids. And reading here, I see there is also a difference of opinions. Builder of the metal shell said use 1-1/2 inch of closed cell because it is waterproof and will insulate better than 3 inches of open cell. Insulation company #1 says use 1 inch of closed and 3 inches of open on top of it to give better Rvalue and to make the walls have less flex and so less noise when the wind blows. Company #2 says no, use only closed cell and do 2 inches and it will have the same R value as the combination of closed and open. These are people who have never done the wood framing separated from the metal framing. The usual way these barn homes are built is to attach the studs directly to the metal. We aren’t doing that for 2 reasons: 1) temperature transfer 2) sheetrock damage due to metal expanding and contracting.
Because we are insulating the wood structure well, and because there is an air space between the insulated metal building and the insulated wood building, husband doesn’t feel that the metal part needs more than 1 inch to seal all the openings (and there are many) and make it watertight.
We have company #3 scheduled to spray in 10 days, so we have plenty of time to second guess our decision. What are your thoughts on this?
答复
Mattie,
1.If you leave 2 inches between the metal frame and the 2x4s, with the 2 inch gap be insulated or uninsulated?
2. What is your plan for the ceiling above the top floor -- also 2x4s filled with fiberglass, or something more substantial?
-- Martin Holladay
Mattie,
还有一个问题：你能描述金属建筑内部的样子 - 将用泡沫绝缘喷涂的表面吗？我假设内部具有暴露的钢柱（柱），暴露的钢梁和齿槽，并且（在这些柱子和梁的外侧）某种类型的钢包层。它是否正确？
换句话说，它看起来像下面照片中的建筑物吗？
.
Martin, I'll answer your questions as best I can, but my terminology may not be right.
1.据我所知,领空不会有任何thing in it and will just be to keep the wood from contacting the metal. It may not be a full 2 inches depending on if a scrap of 2x4 is used for a spacer. One barn home we visited during its construction had 5/8 inch air space and had used metal brackets to attach the wood framing to the metal framing every 10 feet top and bottom. I don't know if that is the plan for ours. It will be attached at all the windows and doors so will have to be attached in places with something, I'm just not sure what.
2. The plan for the ceiling, I think, is 2 inches of foam on the metal above the living area, and insulation in the wood framing. Whether that is 2x4, I don't know.
3. Yes, the inside of our building looks a lot like your photos. Red metal. The columns are larger and just two girts that look further apart than those pictured. No trusses like those pictured though, it's all open. I don't have any pictures of ours inside but will see if I can find one online like ours is made.
How do I add an image I found online?
Mattie,
要添加图像，请单击“注释”框下的“文件附件”选项。将出现选项;单击“浏览”框，然后选择已保存到计算机硬盘或桌面的照片。选择正确的图像后，单击“附加”，然后单击“帖子”。
-- Martin Holladay
Mattie,
If you want to use fiberglass batts as insulation between 2x4 studs, you need air barriers on both sides of the studs.
用某种类型的绝缘层填充螺柱和固化喷雾泡沫之间的空气空间真的更好，而不是留下空气空间。空气空间为对流环和隐藏的空气泄漏路径留下了机会。
-- Martin Holladay
I showed my husband this discussion as well as information I found on convective loops and double wall construction. He has been researching the insulation side more than I have and his brother used to be in the metal building insulation business - here is what he said, but in simple language. Since the metal wall will be insulated as well as the stud wall, it won't be a big temperature difference between the two. We both wonder if it would make a big difference to fill the entire void between metal, but cost is a factor right now and we're stretching it to put 1 inch over the whole building.
The 2 inch air gap will actually be more like 3/4-1 inch when finished but it is necessary to have an airspace for foil faced rigid insulation. Using a 2x4 spacer between the metal and wood framing makes the air space 1-1/2 inch, and the rigid insulation will be on the air space side of the framing. Batt insulation will be between the studs, and sheetrock on the living space side of the studs.
我们已经读过的一切并被建造的人告诉这些是木材不应该反对金属。那些用空调建造它们的人说他们真的很好地工作。那些把木头放在金属上的人说这一开始就很好，但是在它开始有几年，他们开始在建筑出汗和薄片裂缝中存在问题。
我忘了问我们的上层天花板是否将是2x4或其他东西。
Mattie,
It wasn't clear to me (from reading your first post) that you planned to install foil-faced rigid insulation between the cured spray foam and the 2x4 framing. That layer (the foil-faced rigid foam insulation) will definitely improve the performance of the wall assembly compared to a wall assembly without the foil-faced rigid foam.
Since your husband appears to know more about these details than you do, here's what I'm wondering: Does your husband have any questions? If so, perhaps your husband should post them. Otherwise, it feels a little bit like we are playing telephone.
-- Martin Holladay
是的，如果他会发帖会很好。所以我想我会让这一滴，因为他不会去做。