屋顶更换问题；怪异的气流；increasing R-value
This is my first post and its long.. I attached an image of what I think the current setup of our house is. Until the actual roof is opened I won’t know for sure. I’m also new to all this and the correct terms to use. Zone 6.
95％的屋顶是大教堂的天花板，有一个小阁楼。内部天花板是干墙和TG。干墙后面似乎有一层透明的塑料。80％确保TG板后面有石膏板。
I think that the attic air flow is from soffits in the front, these soffits are in an open area with no baffles. Then there is a ridge vent at the top with MDF on top of the rafters leaving a 1 inch air gap to the north side of no where..
I think that on the north side of the house the air is open to a gap that runs down the exterior wall behind the siding.
One reason I suspect this is because we had a lot of mouse activity, then I put copper mesh stuffed into the bottom of this exterior wall gap from the outside and the mouse activity in the attic stopped.
A bathroom exhaust van also seems to lead to this exterior air space! (powder room) There is no exterior vent for it, it is just being run between two floor beams between the first and second floor to the exterior wall. We heated the bathroom and used a thermal camera to check this.
In the front of the house there are also a few vents from the roof/ soffit area that open into the house. These are currently covered with a wood panel and are not air sealed.
We need to get a new roof . The plan is to remove all existing roofing, MDF, and insulation. I want to gut the current one to get rid of all existing pink insulation because of mouse crap in it. The MDF is also not in good shape based on what I saw in the small attic and we have one area that is dipped down.
还有一种可能性,即我们有椽be damaged from water and/or rot. If these are damaged how would they be repaired? (haven’t looked into this yet)
屋顶的后底有加热的冰坝电缆。冰的确会在最小的阳光的后角堆积。
重新构造这种情况的最佳方法是什么？我已经阅读了我在这里可以找到的“隔离大教堂的天花板文章”，但我们似乎有特殊的气流情况。
理想情况下，是否应该关闭墙壁的气流？
How do the open vents to the house play into air sealing? I don’t know the initial purpose of these except maybe airflow for the wood stoves
我们应该如何关注现有的塑料层？
房子里有两个木炉，上面有烟囱。（由于职业不是100％，冬季温度不是恒定的，它在内天花板处的55-80+dEG因使用的热源而变化），如果我们增加屋顶高度，则可能必须扩大管道烟囱。
I would like to use mineral wool between the rafters. I rather not use foam spray if I don’t need to, just a personal preference. I also would like to use a water and ice membrane on the entire north face.
The new roof is likely going to be shingles, we thought about a metal roof but just aren’t sure.
Most articles say to add foam board to the roof sheathing top. If we are removing everything existing is there a way to add height to the rafters and add more mineral wool instead?
如何解决热桥接？
Any input would be appreciated! Thanks for reading to the end.
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答复
How deep are the rafters?
The orientation of the major pitch faces north?
What type of siding?
在第6区中，如果它是未通风的屋顶，则至少需要50％的R在屋顶甲板上方。更多是更好的。对于北方球场来说，欺骗这个数字是不明智的。在第6区中，R49的代码也最小（但通常仍然是经济的。）在带有矿物质羊毛的通风屋顶上击中R49的气隙约为12英寸的气隙，远高于2 x12 rafter的深度。
“合理”解决方案的范围有很大程度上取决于您现有的after深度，该深度尚未指定。
amz，
我们需要更多信息。
1. Many of your sentences talk about the "front" of the house. Does the front face north or south?
2. You refer to MDF, but your sketch shows no MDF. Where is this MDF?
3.您指的是阁楼，但您的草图没有显示阁楼。您能为我们画一个包括阁楼在内的房屋部分的草图，所以我们知道您在说什么？
amz，
您不希望从室内空间开放通风口进入拱腹区域。该通风孔应永久密封。
这是一篇文章的链接，描述了您可以隔离这种屋顶的所有不同方式：如何建造绝缘大教堂的天花板。
房屋检查说我们有10英寸的r子。对不起，我忘了添加。
The siding is T1-11 boards which we eventually will replace or recover.
The front I am calling is the front of the house which is the south side. The roof is sloped down the north side. Its one large rectangle plane.
MDF看起来像从上到下的after子上静置。上方的气隙。我看不到MDF顶部从甲板护套上隔开的东西。
The attic area is small, 6' by 10' or so. This attic area is over a bathroom area only.
Any idea what the vents from the soffit would have been originally for?
I'll assume those are milled 2x10 rafters, which are 9.25" deep, not 10". The most you can get in there and still have a vent space with rock wool or high density fiberglass batts would be R30, which is well shy of code minimum.
如果将纤维素致密，将产生〜r34，这意味着在屋顶甲板上至少需要R35才能在屋顶甲板上具有合理的露点控制。在上方安装自我修复的peel'n'stick和次要组或2x10，您可以在那里堆叠R15摇滚羊毛（3.5英寸厚）和R23摇滚羊毛（5.5英寸厚），它们将留下1.25英寸的通风孔空间，并具有舒适的露点边距，总共有R38摇滚羊毛到R34-ish纤维素。
It sounds like they used MDF for the exterior side air barrier for the insulation on the old low density batts(?). If installed snugly without gaps rock wool doesn't absolutely need an exterior side air barrier, but you may want to install something vapor permeable such as corrugated cardboard insulation baffles side-stapled to the new rafters to reliably preserve the vent space, taping the seams between adjacent baffles for better air tightness. MDF would be too thick to guarantee the minimum 1" unless you compressed the batts. If you go the more rigid board route, half-inch asphalted fiberboard sheathing would be more moisture tolerant than some grades of MDF, and is still sufficiently vapor permeable. If it's asphalted on one side only, the asphalt side faces the vent channel.
With a 3/4" nailer deck atop the add-on rafters for the roofing above that's going to add 10" to the total roof thickness, which is pretty significant. The details of how to fasten the add-on rafters to the structural roof would have to be figured out and reviewed by the inspectors.
“壁板是T1-11板……”
"...air is open to a gap that runs down the exterior wall behind the siding"
T1-11通常是结构性护套，而不仅仅是壁板。描述听起来好像T1-11在某种程度上在它和其他任何护套之间都挂着缝隙吗？
谢谢达娜
I ripped a piece of the existing MDF off and the side to the roof sheathing is black. I assume this may be a asphalted layer.
Adding 10 inches to the roof seems a bit crazy just to meet new codes :( It seems like the only other option would be to go lower inside which would be even a larger construction mess.
I really don't know what is behind the T1-11. I think its just a plywood of sorts. I need to investigate better.
If there is this open air gap from the exterior wall to the roof does this need to be closed and then just have the roof vent to soffits on the rear north slope?
amz，
The description is a little confusing -- but it sounds as if the MDF is a ventilation baffle used to create a ventilation channel. Is there roof sheathing above the 1-inch ventilation channel? If so, what type of roof sheathing -- OSB, plywood, or boards?
Sorry to be confusing, I can only see the roof from the small attic space until its open from above. From what I can tell the MDF is being used as a ventilation channel but I can't tell how its attached to the rafters. There is roof sheathing above this that looks like plywood from the bottom. I made a small hole to look up. I plan to make a larger hole tomorrow to try to see more.
Whatever the existing roof sheathing is will be replaced completely.
amz，
这种情况并不像您听起来那样复杂。我认为您有通风的屋顶组件。
1.打开您的拱腹，以找出发生了什么。密封鼠标高速公路（墙连接）。
2. Install soffit vents.
3.与insulatio椽子之间的隔离n of your choice.
或者，密封所有通风孔，并在现有屋顶护套上方安装刚性泡沫。这是你的选择。
Correcting deficiencies in the roof venting doesn't fix the R- value issue. AMZ expressed an interest in avoiding foam.
岩石羊毛R32s的深度为8英寸，足以继续使用带有更薄的挡板/溜槽的排气2x10屋顶。这与没有屋顶甲板隔热层的情况下一样好。如果在屋顶甲板上方搭配泡沫，则d至少需要7英寸的Polyiso，以露出R32岩羊毛的露点控制，然后依靠屋顶甲板或R34纤维素。但是，由于它是连续的，而不是由Polyiso的Rafter 7英寸热桥接的，即使没有腔体绝缘，也会以U因子为基础。
A thinner solution would be R23 rock wool snugged up to the roof deck with 5" of polyiso above for dew point control. But if you don't have access to the roof deck from below that may be hard to implement.