Attic Rain and How to Prevent It

If you have moisture spots and stains on the ceiling below your roof space, then you may have attic rain. The root cause is relatively humid air from the house entering the loft during winter, encountering cold air, and freezing.

The ice remains there on rafters and on top of ceilings until there’s a break and warmer temperatures return again. When they do, the ice melts and causes the water stains and spots you can see from below.

It goes further than that after extremely cold, long spells causing more significant accumulations. Gravity draws moisture down walls, light fittings and bathroom exhaust fans when the ice eventually melts in spring. There’s little you can do but wait for it to stop

Calgary’s unusually cold winter is causing headaches for homeowners and more business for roofers although ventilation is not the answer. Freeze-thaw cycles have traditionally prevented excessive ice accumulation but this is not happening this year.

There Are Two Types of Attic Rain

In the first instance you have a large opening into the attic space, or unsealed exhaust vents pouring humid air into the loft. These are easy to spot if you enter the roof space and look for localized ice, and are relatively easy to fix.

In the second instance, you find ice throughout the attic when you look. This indicates high humidity is finding a way through so there is something wrong with your home’s system. Increasing loft ventilation will not fix this. It will just draw more humidity through.

How We Fix These Two Problems

We locate the holes causing the problem by slightly reducing the pressure inside the house, after installing a temporary blower door in an existing opening. Negative pressure draws colder air down from the attic which we can detect with a thermal scanner. Placing the back of a hand over the leak confirms the strength of the flow.

We can then close the leaks, on the attic side wherever possible. Ceiling fans and down lighters are likely to be major causes. We undertake to conceal the repairs wherever possible. However, there may be times when we need to replace a fitting to achieve this.

Valiant Exteriors knows how to stop humid air from entering attics and freezing in winter. If you have this problem, you need it attended to promptly before you have permanent ceiling damage. Please call us on (403)829-1661 or message us at [email protected] for a free estimate based on extensive experience.