When the average person sees moisture around the upper level of a building or the underside of the roof, a leak is often the first concern that comes to mind. While you should undoubtedly not rule out a leak if you encounter this problem, it's important to understand that roof condensation can also be a possible concern.
In short, roof condensation is the result of poor ventilation in the area around the roof. As your building heats up throughout the day, much of the heat generated will move towards the upper level of your building. However, when the air temperature outside is cold, the area just below the roof will also feel cool.
The problem occurs when the cool and warm mix. Once the two collide, the cool air dominates and works o quickly cool the warm air. The result of this process is condensation. Depending on the reason for the moisture, you should be able to correct the problem with new venting to control ventilation in the area or with the installation of a vapor barrier to your existing roof.
While the thought of roof condensation might not send you into the same level of panic as a roof leak, it is an issue that comes with all sorts of risks. It's important to keep in mind that moisture damage is all the same. Whether it be mold or rotting, the moisture from condensation can still target the wood structures that support your roof, and as a result, weaken your roof. Condensation issues can also cause damage to the insulation that is installed in the roof area, which can cause temperature control issues and increase your building's heating and cooling costs.
Detecting a condensation issue is likely a lot easier than you might suspect. First, pay attention to when you see the moisture most often. For instance, if you only see the moisture buildup when it's raining outside, it's likely that condensation is not to blame, but instead a leak in your roof that needs to be repaired. Second, damage from condensation is often more widespread, in that condensation can affect a larger area, whereas, with a leak, the damage is more likely to be restricted to the specific area where the leak occurred.
If you suspect a roof condensation or another moisture-related issue with your roof, you need to contact a commercial roofing professional as soon as possible.