我应该向平屋顶添加新的护套吗？
Chris Bowman|发布了能源效率和耐用性在
I own an old brick multi family building.
I am planning on getting five layers of an old built up roof torn off and replaced with 5” of polyISO and a TPO covering. Insulating from below is not an option right now.
Longevity and performance is always a top priority for me when getting a major repair done. Is it worthwhile to add an air barrier like zip sheathing on top of the roof deck before installing the new rigid foam and TPO?
替代方案只是简单地录制旧屋顶装饰的关节帮助创造一个良好的空中障碍？
Any advice would be helpful, looking to do this right the first time and not have to worry about the roof for many decades.
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嗨克里斯，
I'll give your post a bump. I suspect the experts will say you want the air barrier close to the thermal boundary.
What do you anticipate for an total R-value for your 5 inches of polyiso? R-30 maybe? Are you planning to add air permeable insulation under the roof sheathing as well?
Also... Are you using reclaimed foam? It's a lot cheaper than new stock.
Hi Steve,
Much appreciated! The r-value of the polyISO should be around R-30 maybe R-32. Have a few quotes pending for reclaimed polyISO, much cheaper! I may add rockwool insulation underneath at a later date as funds permit but as of now, the cavity between the upstairs ceiling and roof is uninsulated. (Building was built in 1907) Removing all the plaster and lathe in the ceilings and insulating from underneath would cost me almost as much as the new roof.
我可以逃脱只需抓住屋顶甲板的接缝并加入机械连接的蒸气屏障？或者是在屋顶甲板上加入拉链护套吗？
克里斯，
到你的前两个问题，是的。绝缘下方的空气屏障在所有情况下都是一个好主意。屋顶甲板的材料和条件如果您计划胶带接缝和穿透以充当空中屏障。在所有穿透和接缝处添加密封的膜更有可能是更快的，并且与拉链护套一样有效。
Your climate zone matters in determining relative risk for condensation if you plan to add rockwool insulation underneath the deck, and also whether or not additional vapor control measures are needed beyond an air barrier. In most but not all cases an air barrier is sufficient.
https://www.buildingscience.com/documents/insights/bsi-019-uplifting-moments-roof-failures
Best,
j
Most retrofit guides show an air barrier bellow the foam:
https://www.buildingscience.com/file/5763
This makes sense as you don't want interior air to make it between the seams of the foam and condense on the roof membrane. How best to do that is up to you. I generally go with full peel and stick under foam for small flat roofs. I like the fact that it acts as secondary roof in when the roof membrane inevitably fails.
谢谢你们所有人的乐于助人的答案。我很高兴我在这里发布。2015年ZEHR正是我正在寻找的！不确定我是否要将对待的胶合板贴在我的栏杆墙上，但这不会影响砖栏的冻结/解冻周期？
I’m in climate zone 4, but very close to 5.
您是否对剥离和粘贴空气障碍有任何建议？
无论您的屋顶绝缘，膜细节或添加胶合板，砖护栏都暴露在冻融周期。限制暴露于散装水可减少冻融风险。
Adding insulation to the inside of the walls is a different story.. If you ever plan to do that, the parapets can give you a sense of the freeze/thaw resistance inherent in the brick itself, especially if they run a few feet above the roof and are more exposed.
Go with whatever is available locally. For me it tends to be Henry/Grace/Soprema. Anything without a granular surface will work.
P.S. Make sure they install the foam in layers with staggered seams. This reduces the heat loss through the gaps in the foam as they tend to shrink over time.