Dryer Vent Ice Dam

Mark has an ice buildup and ice leaking out of his soffit where his dryer vent exits his home. It's pretty severe. Here's his story:

"I am getting icicles on the side of my house near the dryer vent. This happens in Nebraska sub-zero weather. This side of my house faces the northwest.

I made sure the duct extends all the way to the exit. The vent flaps on the hood outside properly open slightly when the dryer is on.

There is no obstruction that I could see in the duct when I shined a flashlight in the duct.

Do I have a problem with my siding and/or dryer vent that should be corrected?

I am concerned this could, in the long term, rot the under-layer siding and/or get moldy underneath.

Or it could just be the condensation that I have to deal with in these conditions? Here's a photo of the ice."

This amount of ice indicates vast amounts of water vapor are seeping behind the siding where it WILL CAUSE rot and mold. Photo credit: Mark

Mark, I know exactly what's going on.

First and foremost this is a serious problem. You're correct that it's condensation from the hot water vapor from the dryer. You're going to deal with this in the spring or at an earlier warmup.

If you don't you will have rot and mold for sure.

If you have access right on the other side of that wall in the basement where the pipe is, it's going to be easy.

You just need to disconnect the pipe from in the basement and pull it OUT to the outside.

It's best if you can pipe from the basement to the outside wall louvered wall cap as ONE SOLID PIPE with no joints. Also, you MUST get access to the soffit once the pipe is reinstalled.

It’s imperative that you insulate completely around the pipe. It's got to be WARM so condensation is at a minimum while the dryer operates.

You will get some condensation in the pipe no matter how well you insulate it. The longitudinal seam in the pipe must face the SKY so any condensate heads back to the basement.

Slope the pipe back to the basement if possible so condensate collects in the basement, not in the pipe in the wall.