屋顶/墙交叉口的R值
我位于纽约地区区奥尔巴尼5A区。
我购买了一个破旧的房子，并正在做一个深的能量改造。壁板将被撕掉，大部分是腐烂或柔软的，我将安装Huber Zip，它应该提供空气和蒸汽屏障。Larsen Trusses将安装，腔深将是12英寸，〜R-40。
屋顶是12:12，峰值大约10英尺高。大约三年前据说，新的沥青瓦片被安装到了它们似乎是体面的。屋顶框架是尺寸2×4的24-30“o.c.有一个Shoddily建造的宿舍，将被删除。从探索周围的宿舍，看起来有1x装饰，木制奶昔，1/2“胶合板，焦油纸，然后带瓦。外墙是球囊框架，双2×4（尺寸）顶板。二楼的天花板托梁大约为7“。
我已经附上了一个基本绘图的图像。棕色代表着框架，绿色是纤维素（没有将其延伸到像屋顶椽子上的天花板上，因为清晰的圆顶），橙线空气屏障。
My concern is the R-value achievable around the top plate and roof/wall intersection. Once the 2″ ventilation channel is considered, the top outside corner of the ceiling joist has about a 2.75″ cavity that can be used for insulation which ultimately presents moisture (cold spot on the ceiling) and energy issues. However the minimum depth from the top of the double plate when including the joist cavity is 7″ which is acceptable if spray foam is used.
Now since this is a complete rehab project, there is no issue with running a continuous interior soffit to allow for the proper insulation depth. Anyone have any input on whether that would satisfactorily address the issues? It seems like it would reduce, but not necessarily eliminate, the issues.
我已经考虑过撕下整个屋顶结构，并与平坦的屋顶（劳动力由我做，而不是喜欢在陡峭的屋顶上工作），因为天窗必须脱落，代表约1/4的屋顶区域。我最初担心2×4的24-30“o.c，但它似乎在过去的100年里工作了。它确实有一个漂亮的30年屋顶。我喜欢12:12外观。它会增加费用。最终，我正在努力证明屋顶/墙交叉口的能量问题是重做整个屋顶结构的优点。
GBA Detail Library
由气候和房屋部件组织的一千个建筑细节的集合
答复
Upstate,
这绝对是一个冷角。它将始终受到湿度和模具。您经常在像那样的角落中看到发霉的干墙天花板 - 特别是在浴室里。
The best solution is to install several layers of rigid insulation on top of the roof sheathing. Of course, that means you need new roofing, which is expensive.
Upstate,
您可能对2008年10月发行的本课题写的文章有兴趣能源设计更新。该物品被称为“防止寒冷天花板上的模具生长”。
Reading it will take patience, because I'm attaching the article as 11 image files. I apologize for the awkward format.
Here are the last 5 image files.
I guess there's no chance the added wall depth could go to the inside?
Is raising the roof and cobbing in an energy heel in a situation like this even remotely feasible?
再思考 - 用高R泡沫填充墙板固体上方的空间，并使用这些引入屋顶的通风进一步：http://www.cor-a-vent.com/in-vent.cfm。I have no idea though if this might introduce extra problems in snow country - Martin?
我认为这个问题更多地具有比托梁腔的热桥接。托腔腔提供了大约9“的喷雾泡沫可以提供足够的R值的深度。这将是一个相对较小的体积，所以我认为费用将是可容忍的。
Once the flooring and ceiling is finished I will have about 7' 3" ceilings on the second floor which would make an interior insulation approach very difficult.
I am hesitant to insulate the interior of the walls due to cold sheathing concerns, loss of space, and maintaining the air barrier. Also, there is brick in all of the stud cavities which I am leaving exposed on the first floor and unsure about the second.
The retrofitted energy heal is an interesting idea. I have attached another image with an idea. Basically continue the larsen truss up to the depth of the ceiling insulation. The top of the larsen truss could be essentially flat, though slightly sloped for drainage or it could integrate at another angle. Venting can be achieved through channels above the insulation. I do however wonder about aesthetics and of course the building inspector since the larsen truss would now carry a roof load.
Upstate, you could probably make that work, in fact it's similar to an elegant traditional detail called a swept eave. I'd go with a minimum 4/12 pitch for the sweep so you could stay with the same roof finish. Eaves load could be taken back to the original wall plate with a simple strut. Don't know what Martin will think of the brokeback profile, it's similar to one of the no-no's on his roof design article, from concerns about snow retention. I'm told though that the swept eave is a classic traditional detail in Denmark, where snow is hardly unknown.
顺便说一下，我认为你需要尽可能高的天花板纤维素的全部深度。IIRC博士Joe建议你在墙上的盘子上有同样的r。它可以看起来像这样：
我不是雪国家的横扫屋檐的粉丝，因为他们肯定会增加冰水坝的机会，他们干扰了从屋顶清理的冰块。
但这个想法可以工作。如果你这样做，不要忘记安装一系列冰和防水罩，或者在切换到传统屋顶之前，请考虑用金属闪烁金属闪烁的屋檐。