Let Your Container Breathe to Keep the Inside Air and Contents Safe

Proper Ventilation is the Key to a Healthy Living Environment


By nature, shipping containers are sealed up very tight so that the goods shipped inside of the containers will survive the trips across the ocean in every kind of weather condition you can imagine. In addition to weather, shipping containers must protect against the corrosive saltwater and salt air always present during ocean crossings. Those who have have built or designed houses, had one re roofed or turned an attic area into a living area know that proper venting is critical to keeping maintaining a healthy, comfortable environment, this same theory applies to containers.


I won’t get into the science here of how and why an improperly vented building envelope or container in this case can create ice conditions on the roof during the winter months causing roof leaks due to freeze thaw cycles or how condensation will occur on the interior creating the perfect environment for mold conditions to develop.  Some have reported so much condensation inside containers used for storage that it is actually dripping large rain like drops from the container roof onto the contents. I’ve seen articles suggesting the use of gluing foam board insulation to the inside of the roof being offered as a solution to dripping condensation but this is the worst thing you can do. The condensation will continue to develop between the steel and the foam but the foam will trap the moisture between it and the roof causing the roof to rust from the inside. In order to add insulation to the roof you need to have a vented air space between the roof and the insulation. This would take some work and unless you are trying to keep heat in the insulation is not doing anything that simply adding vents without insulation wouldn’t have cured anyway.

Like a properly functioning roof system on your home, your shipping container should be vented in order to keep the interior healthy from mold and the contents dry. You can install fancy automatic vents or vents with solar powered fans or just simple vents, it doesn’t matter. In this situation, placement is more critical than style. A single vent is not going to help; you need multiple vents to create an air flow through the container in order to remove the humid air. Some have cut standard roof vents into their container roof and this works well, but I prefer to minimize future leak potentials by minimizing roof penetration so I like to place them high on the side walls. At the bare minimum, you should install four vents on the side walls about 4’ from the corners up near the roof with another set of vents on the middle of the side walls on 40’ containers. While not perfect it will move some air and limit some condensation.
LOUVRE AIR VENT VENTILATION GRILLE EXTERIOR OR INTERIOR USE 100MM

vent 1 storage containers for saleAs air warms, it rises so the best fix is to use this convection by installing vents on all four container sides on the side walls down by the floor and up by the roof (and an extra set on the middle of the side wall on 40’s) creating an air flow through the entire container.

You can use almost any type of vent; just put some thought into the type of vent you select and how you position them so rain does not enter the container. Make sure you cut a snug hole and weld the vents in if possible, if you don’t have access to a welder then properly flash and caulk your vents, remember, in addition to moisture you want to make sure rodents and other small animals can’t take up residence in your container. Crawl space vents or foundation vents work great for this application, they mount flush are easy to install and can be painted. Once installed, the results from a properly vented container will be immediate and long lasting. Please contact me if you have any questions or need some help.

2 Comments
  • Caleb
    Posted at 10:42h, 22 November Reply

    A vent is definitely a necessity for crawl spaces. It is the best way to help prevent mold from growing and letting moisture out.

  • Brian McDaniel
    Posted at 19:20h, 30 April Reply

    Need a quote on some vents for my 20ft storage containers been looking for a while. Conex is the name on it. Please contact me as soon as you can Thank you

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