Attic Rain

CBC Calgary recently reported on an unfortunate instance of Attic condensation termed “Attic Rain”. You can read the article HERE. As Attic insulators we come across this phenomena during the Winter months.

It is caused by a combination of 3 factors: penetrations in ceiling Vapor barrier, insufficient Attic insulation and insufficient Attic ventilation. The first cause is difficult to remedy. Once your attic is insulated it is very difficult to find vapor barrier penetrations, akin to a needle in a hay stack. The most prudent process is to remove all current insulation, seal penetrations using poly or spray foam and then re-insulate.

The second issue is much more easily addressed. Low spots or missing insulation can be topped up with new insulation during a simple attic upgrade. These low spots can cause excessive heat loss in a localized area resulting in moisture concentrating in a specific area. During winter months this moisture will freeze to the underside of the Roof, the coldest place in an Attic. During the day when the temperature rises the frost can melt. This cycle of freeze-thaw is what eventually leads to condensation, or Attic rain.

The last issue can also be remedied, but involves a detailed investigation of both Intake and Exhaust ventilation. Most houses draw fresh air into their Attic spaces through the Soffit cavity. Newer houses now utilize Lower roof intake vents that are installed on the roof. This is due to recent changes in Calgary’s fire code. Air is expelled from your Attic through exhaust vents that are installed near the top, or ridges, of your roof. Your attic relies on this air exchange to help equalize the temperature between inside and outside of your Attic, as well as expel moisture. Improper venting will cause heat and moisture to become trapped in your Attic space. The build-up of this heat and moisture is what feeds the freeze-thaw cycle during the Winter months and can lead to condensation and Attic rain.

IDEAL recommends that you take a look into your Attic space once a year for signs of condensation and air movement. We are happy to schedule an inspection where our qualified team will visit your home to assess these factors and positively contribute to your Homes comfort and quality.