How do you seal windows from the exterior for water and air but not create a vapor seal?
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How do you seal windows from the exterior for water and air but not create a vapor seal?
Piyush Prince
Nov. 7, 2018Last updated: Aug. 2, 2020
I am following your technique to seal the windows from inside that is to use Rockwool to insulate the gap and tape for water, air and vapor barrier. I am concern that taping it outside might cause the vapor sandwich which I want to avoid. I am not sure what you have done for 2015 model home for exterior.
Your help on this is highly appreciated.
Thank you.
I guess you saw ourDIY video onhow to install windowsin our Edelweiss House videos. If you did then you knowwe tried two approaches, backer rod and caulkingas well astaping the window to the rough opening, on the interior side, no tape was installed on the exterior. If there is no hole where air can escape on one side of the wall then it won’t enter on the other side, so one air barrier is enough. We covered the exterior gap with wood, and caulked at the joints and junctions to prevent water from entering.
We were really happy with the air seal the tape provided, and when we conducted our blower door test we didn’t find a single leak through the taped windows but we found a few where it was caulked. Though that is more than likely a quality of work issue, if you are very cautious with your tape installation it’s a bit easier to ensure you’ve sealed it properly that with caulking in our experience.
As for your moisture concerns, there wouldn’t be a lot of moisture buildup in an airtight space that small even if you did tape both sides. Think about it like any section of a typical wall – you have a vapour barrier on one side, insulation, and wood sheathing on the exterior. With our window installation technique we had the same: a vapor / air barrier (tape) on the interior, insulation in the cavity, and wood on the exterior. In The absence of any leaks, the source of any moisture in there would be the framing lumber itself, which as an ability (or at leastshouldhave the ability) to dry to the other side.
The most important thing to make sure there is no moisture buildup between windows and rough openings is to prevent any air leaks, as warm humid air leaking out in winter will deposit moisture in that very spot you are concerned about. Again, that’s why we are more confident in the tape.
很多人都用喷雾泡沫来处理那个洞,我们自己也发现这种方法会导致更多的水分问题。原因是喷雾泡沫会变脆,在任何转移的情况下,降低其长期保持适当空气密封的能力。A high-quality tape (and I stress a HIGH quality – Airstop, Siga, Delta多波段是一些名称)将允许一定数量的运动和不影响空气密封。你的典型的一卷廉价的建筑胶带在相当短的时间内变得脆弱,容易开裂和不粘。When air-sealing a home, its very much worth the extra money it costs to get a better tape.