The cold winter weather can bring all manner of property maintenance issues, but few can cause as many headaches (or large repair bills) as unchecked condensation.

“You’d be surprised at what condensation can do if it isn’t looked after,” says Jack Albert, Associate at RJC Engineers (RJC). “Once that moisture is present, it can damage finishes, drywall, flooring, and even lead to air quality and health concerns.”

According to Albert, condensation occurs when interior humidity levels combine with colder surface temperatures, usually at windows and doors, leading to moisture in the air condensing on those surfaces. The quality of the windows, as well as the details at the perimeters where windows transition to adjacent systems (e.g. precast, concrete or brick), are often major contributing factors. Air barriers and thermal control layers are used to protect these connecting points but can fail over time or be improperly installed.

Although condensation can happen all year round, it is especially pronounced in colder seasons. One reason is that air conditioning equipment is no longer removing humidity from the environment; another is that condo owners will often use humidifiers to combat cold and dry air, and enhance comfort. Additionally, in the shoulder season (particularly, the fall), condensation often shows up as nighttime temperatures drop but interior humidity levels remain high, especially with ERV mechanical systems.

Fungus and dampness near window

Condensation can be a common issue in older buildings with less thermally efficient windows and walls. It can also show up in newer buildings due to poor building envelope detailing or lack of dehumidification.

“It is something that we address all through the year, but typically more calls about condensation come in the winter when the conditions are more extreme, such as fogged up windows,” notes Albert.

Preventative ways to control condensation 

Appropriate window detailing will often prevent condensation; however, in the absence of that, residents do have a few techniques at their disposal. These include:

• opening blinds to allow heat to get to the windows
• using exhaust fans when cooking and washing
• and, generally monitoring and controlling humidity levels throughout the season.

In cases where condensation has taken root over long periods of time, or if the above steps are not sufficient to eliminate the problem, Albert says it pays to call on professionals: “This isn’t something you want to leave unchecked over a long period, because the repairs will add up.”

To that end, building envelope professionals like Albert will work with mechanical engineers to evaluate those HVAC systems and make sure they’re both working properly and in concert with the building envelope system. They can also perform infrared thermography scans, conduct air leakage tests, carry out thermal analysis, and review building designs to find the root cause of the issue.

“There’s always the possibility that the walls or windows weren’t constructed properly to begin with, in which case we’d move to a repair or retrofit,” Albert notes, adding, “Of course, being proactive about condensation is a better bet. That’s why we also work with developers in the early stages of a development to assist in design detailing and specification during the design phase to reduce the risk of condensation in the first place.”

Condensation may not look like much of a problem at first glance, but like all building performance issues, it pays to take notice before it becomes serious.

Jack Albert is an Associate with RJC Engineers’ Building Science and Restoration. To find out more about what RJC can do for you, please visit rjc.ca or contact Jack Albert directly.