The Roofing Resource Blog

What Causes the Problem of Roof Condensation During Winter?

Mon, Mar 2, 2015 @ 08:00 AM | Exterior Pro Roofing

With a slope or flat roof, one of the things that must be kept in mind is the threat of moisture condensation during the late fall, winter, and early spring. Several factors combine to create this problem, which can rot timbers, cause mold growth, aggravate allergies, and more. However, one of the most obvious and disturbing things that can be caused by condensation is the appearance of roof leaks.

ceiling_stains_from_condensation on_roofCondensation Leak

Dripping ceilings are almost always blamed on leaks in the roof, but condensation can cause this effect even when the roof's outer surface is completely intact. That's because once the condensation builds up enough, it starts to drip out off of the saturated beams and out of the insulation. Since the interior ceiling isn't waterproof, the condensate drips on through. This can cause damage not only to the ceiling, but to whatever equipment or stock is beneath the dripping points.


A few factors work together to make condensation a bigger problem during cold weather. Warm air tends to hold more moisture, and it also likes to rise. This brings moist air from the building up through the ceiling. Moisture also likes to condense on cold surfaces, and the area between the ceiling and the roof is full of these surfaces. Finally, a lack of ventilation gives the moisture no way to get out of this semi-enclosed area. This leaves the moisture with nowhere to go but back into your building in the form of rain-like drops.


Needless to say, this type of dripping needs to be fixed just as quickly as a standard roof leak. If water is allowed to remain in the interstitial space above the ceiling, rot and mold will set in and cause significant damage to the building. This part may be obvious, but trying to fix this problem yourself can be very frustrating. After all, if you're looking for a hole in the roof but there isn't any, you could spend hours up there for nothing!


Even if you realize that condensation is the problem, fixing it is a lot of work for an individual. There are many factors to keep in mind in order to get the condensation problem fixed right. Some of these factors include whether the roof deck is meant to be cold or warm, how much space there is for ventilation, and how close other buildings are to the area that need to be ventilated. For example, if there's another building jammed up against one side of the roof, there isn't going to be room for side vents in that area. Instead, the vents will need to stick out of the top of the roof.

roof_ventAnother thing that makes fixing this problem a job for a real roofer is the variety of solutions available. Most moisture control methods include some form of vapor barrier as well as steps to improve ventilation. The roofing company will know about all of them and can choose the best one for your roof type and the specifics of its construction.

Having real roofers do the work also gives you other important benefits. You won't have to crawl around in tiny spaces or wake up the next day as stiff as a board from doing a bunch of work that you aren't used to. Not only that, they will warrant their work, so you don't have to worry about getting back up there to do the job again later on. The threat of having to redo a job is one of the biggest drawbacks to doing work yourself. Skip that risk by hiring a roofing company instead.