Shipping container condensation?

[MNBobcat]

Hi All,

I just got two 40-foot high cubes to store stuff that I cannot have destroyed

I have read here some talk about condensation issues and some of you installing whirly vents


What has been your experience with condensation? Have you had issues?

If you installed a whirly vent, do you have a photo you could share?

I would appreciate hearing any and all advice! Thank you!

 

[quicksandfarmer]

Condensation is a symptom of high humidity. Even if you don't have condensation, if you have humidity above about 60% you're going to have issues with mold, mildew, rot and rust, depending on what you're storing.

The best way to control humidity is to run a dehumidifier. If a structure is airtight and watertight running a dehumidifier doesn't take much energy, it just needs to remove whatever moisture leaks in through air or water. Of course that assumes you have electricity.

Ventilation is useful for controlling humidity if the outside dew point is lower than the inside dew point, or if there is a source of humidity inside the structure, like water leaks, people or plumbing fixtures. I don't see that in a storage container.

 

[RNeumann]

When the inside and outside container temps are different you can get condensation. The vents help keep the temps inside and out about the same. The “dew point” will also play a role.

 

[Roadworthy]

If you can insulate the inner wall of the container to prevent contact with air the humidity is less likely to condense there.

 

[EddieWalker]

The best way to deal with condensation is air flow. Heat rises. Cut a vent into the bottom on the wall at one end and then install a roof vent at the opposite end of the container. The difference in temperture is enough to create air flow through the entire container, which will reduce the amount of condensation significantly. I'm in East Texas and we have significant humidity. My container remains dry on the inside. If there is any moisture that forms, it's minimal and after about ten years, I haven't noticed any damage from it, staining or wet areas. This is also how a house attic remains dry.

 

[Alien]

We bought 2 new 30 footers about 8 years ago. They had small vents in them. We don't get humidity or frosts/cold here so have never had a mould or condensation problem. They do get darn hot inside them though. Some days I just leave the doors open as it can get up to 60 deg Celcius inside them. You have mould, we have heat.