Hello Green Building Advisor Professionals,

我们在2020年秋天在艾伯塔省卡尔加里完成了一份100多年的房屋的工作。2月22日星期一^nd2021年，我接到了所有者的电话，通知我他们正在泄漏。虽然我承认我们有时会犯错误，但这听起来对我来说并不正确，所以我去了调查。

我们刚刚从一个冷的快照中出来，平均每日温度低至-20°F（-28°C）大约两个星期。在周一，他们注意到水从天花板中流出，过去几天的温度迅速上升至平均温度 +40°F（4°C）。

前一周，我碰巧是另一个密封不良的房子的阁楼，我自己看到了在屋顶甲板的底面形成的霜冻数量。我一直都知道它可能发生，但是我被多少人震惊了。不幸的是，我没有分享这种情况的照片。

我相信，霜冻在两周的极度寒冷中建立了，然后在白天在一天中的一天中迅速融化。强化了这一理论是在问题区域中，屋顶甲板的整个底面是湿的，无法检测到水的点基。此外，我们在该区域使用了剥皮膜，使水很难从外部渗透。

With the building’s age and the hodge-podge of renovations and additions onto it, the roof structure and attic space are bizarre. I would describe the roof as a sort of Mansard style. But that does not quite get it right. It is more like a hip roof with its top cut off and replaced with a flat roof. The sides are 6/12; the top flat portion is close to a square, so all the sloped pieces are relatively equal. At the front of the house, there is a dormer that extends over a covered porch. This is where the water was noticed, luckily not inside on drywall.

窗户向其他阁楼开放。但是，与其以相同的方式被隔热，而是堆积了几个玻璃纤维棒，从而减少了两个阁楼空间之间的开口。在覆盖的门廊的一部分上，没有隔热材料。然后，屋顶的这一部分被冷空所包围。没有迹象表明阁楼中央部分中的凝结或霜冻形成。

在roreof之前，屋顶顶部附近有四个阁楼通风孔（Duraflo 6050）。它们位于屋顶平坦部分下方的倾斜表面上。由于屋檐不向阁楼空间开放，因此没有进气通风。根据制造商的说明，我们在屋顶的底部和顶部三分之一的三分之一中使用了线性通风孔，以实现我们的50/50摄入量与排气率。我们的进气口之一位于问题发生的窗户中。我们还提高了通风的无净面积，以符合我们的本地代码。（在某些条件下，绝缘天花板区域的1/300或绝缘天花板区域的1/150）。据我所知，这些比率并不基于任何特定的科学。

The homeowner informed me that their thermostat was reading humidity levels of about 30% and lower during the cold snap. They got a small humidifier to help with interior comfort but did not run it long. Only as much to bump up the humidity by about 5% or so. They are new owners; this is their first full winter in the house, so cannot say if the problem has occurred before.

关于half of the interior ceiling was redone before reroofing. Hopefully, sealing was done properly around the perimeter, at seams, and penetrations for lights, etc. The other half of the ceiling has no vapour barrier and likely no extra sealing around penetrations. The access to the attic is not mechanically held in place, and there is no gasket for it to seal against.

I’m convinced the issue was condensation in the attic. It’s a widespread problem with the dramatic temperature swings we experience. But what is my best bet to address it?

Many companies in the area would throw in more ventilation, but according to some articles I’ve read here, additional ventilation is not always the answer. I’m a little worried the shape of the dormer in relation to the rest of the roof might be creating a dead air space where moisture can’t easily escape. (I moved the batts blocking it up to encourage more airflow between the two attic spaces.)

Should I suggest focusing on sealing between the conditioned living space and the unconditioned attic? Sealing penetrations, putting in a gasket at the attic access, etc.

将遮盖甲板上的阁楼部分绝缘至与房屋其余部分相同的水平吗？

Or will it be some combination of all three, additional ventilation, sealing, and insulation?

I want to come back to the homeowner with a potential solution that is well thought out, rather than swinging wildly and hope I hit something that works.

Thank you all for your time. I will appreciate any feedback or suggestions you may be able to offer me.

Ethan