The majority of ISO shipping containers do have some vents fitted in the long sides of the units, at the top of the container wall, to allow for ventilation to try and reduce the risk of condensation build-up. However, these vents have to be small to ensure that no water enters the container on its voyage. And due to their size, limited air flow is achieved so, condensation can still occur. The vents in a shipping container are approx 1 inch (2.5cm) square and are covered with mesh to prevent bugs and insects getting in and out of the container. You will get 2-10 vents on a 20ft container and 4-12 vents on a 40ft container.
To minimise the risk of condensation, you can opt for one of our high-spec 20ft shipping containers. These units have 10-vents allowing increased air flow through the container which will help to reduce condensation when compared to a standard container. You will always find new (One trip) shipping containers suffer from condensation less than a used shipping container.
However, in our experience, to effectively reduce or eliminate the risk of condensation, we recommend installing additional ventilation on opposite sides of the unit to allow cross-ventilation. For a 20ft container, we recommend installing 2 to 4 vents. Fitting one vent is of little use and a waste of your money as the air flow will be much more effective with a minimum 2 vents.
If you’ve already got a shipping container, we can supply louvre vents for you to install yourself and if you’re buying one from us, we can install the vents prior to delivery.
Our louvre vents are made using extruded aluminium and are fitted with a wire mesh to keep unwanted ‘guests’ out of your container. Our most popular vents are 350 x 350mm and 500 x 500mm but, we do have other sizes available.
Whilst fitting additional vents to reduce condensation, consideration must be taken regarding the materials being stored within the container. For instance, products with high moisture content such as cardboard, books, paper etc. will increase the level of condensation within the container. The same is true for pallets. New pallets have a very high moisture content so, we recommend you let them dry out first or use plastic pallets.
Aside from problems with condensation, additional ventilation is normally fitted to containers that house equipment that is likely to give off a large amount of heat, such as a biomass boiler.
Of course, if you want to make absolutely certain that condensation does not occur in your container, we’d recommend looking at other options such as applying Grafo-Therm to the ceiling of the container.
Grafo-Therm is a condensation prevention product that is applied in depot and then allowed to dry before the container is delivered to you. It’s very effective at absorbing moisture with a typical 1.5mm thick coating being able to absorb about 1litre of moisture per square metre.
If you intend to use the container as an office, you may wish to consider having insulation and ply-lining installed. This insulation will significantly slow the rate at which the inside of the container heats up and cools down. This will prevent condensation forming and help maintain a more even temperature and for the colder months. We can also install a complete electrics package including lighting, wall sockets and heaters. Some customers have also run their own de-humidifiers from the installed electrics to ensure any moisture is removed from the sir, completely removing any chance of condensation build up.
For more info on tacking condensation issues in shipping containers please feel free to check out our ultimate guide to shipping container condensation treatment options. If you have any questions on this please feel free to contact us (Our offices are open 08:30am – 7pm weekdays) or if you are looking to source a shipping container for your own use, either for storage or for export use then please feel free to browse our online catalogue for the biggest online range of shipping containers and accessories for sale in the UK.