Why do I have Moisture on Basement Support Beams?

Steepdriveway asks,

There are small moisture spots on the steel support beams in my basement. I could be wrong but to me it seems like they originate from the inside of the beams. I tried priming and painting them with Rust-Oleum oil based primer and paint. After that didn’t work I tried again using the primer for rusty metal with another coat of paint. I don’t get water into my basement and I run a dehumidifier during the summer. Can you tell me what is causing them and what do I do? Thanks! I always learning something from your show!

Our Answer

Water leaking from inside a steel beam? Now THAT would be quite a trick! The problem is actually a lot simpler./ What you are sein is simply condensation. The basement air is damp, and the steel beam cold. As that warmer, moist air strikes the beam, it release moisture which condenses on the beams surface, ultimately showing up as drips that could appear likes it coming right out of the beam!

The solution is to reduce that humidity. A dehumidifier is one approach, but there are many other things I’d do before that. Primarily, you need to reduce the volume of water that is close to your foundation outside, by carefully and methodically extending downspouts, keeping the gutters clean and regrading the foundation perimeter if necessary. Follow the advice in our post about how to stop a leaking basement. Even though your basement isn’t leaking, the very same principles apply.