One of the most important points for constructing your shipping container building is making sure you get your insulation right. Failure to do this will cause you a whole host of issues such as dampness, rust, condensation, and highly fluctuating internal temperatures.
Equally important to insulating your container home is ventilating it properly. Without providing your container with effective ventilation, whether passive or mechanical, serious problems can develop with your newly built home. Ventilation is even more important when we consider tiny shipping container homes which are less than 600 square feet, because any ventilation issue is enhanced due to the small space.
Shipping containers are designed to be inherently airtight. This is due to them being used to ship goods in all kinds of weather across the ocean. When goods are inside of containers they must not be exposed to corrosive saltwater!
When we use shipping containers as habitable buildings, this can cause issues. Buildings require ventilation. Today we are going to address exactly how you can ventilate your shipping container building.
Problems Caused By a Lack of Ventilation
Poor ventilation can go be described in two ways. You can have a home which has a lack of ventilation and doesn’t allow the movement of external air to enter your shipping container. You can have a home which provides so much ventilation that it is either impossible, or very expensive, to maintain a consistent temperature inside the container.
Having poor ventilation within your container can cause harm to both your home and the people living inside. One of the biggest problems caused by poor ventilation is mold.
Mold is a fungus which when left untreated can be very expensive to remove and when its fumes are inhaled by a human can cause harm.
Poor ventilation has been linked with numerous human diseases such as pneumonia, dry eyes, and nausea. In addition, it has been linked with respiratory diseases, the most common of which is asthma.
Poor ventilation can also lead to a buildup of condensation which can cause your steel containers to rust. This rust can also affect any metal pipework (such as your plumbing). Repairs to rusting containers can be a time consuming and costly job.
Poor ventilation can lead to dampness which creates musty odors. You’ve probably smelled this before if you’ve walked into an old room which hasn’t had any fresh air for a while.
Because the air has nowhere to go, any scent within your home will linger and cause a buildup of generally unwanted scents.
Enemy #1: Condensation
A lack of ventilation can cause a whole host of problems, but perhaps the biggest problem it will cause is condensation.
Condensation is the collection of droplets of water on a surface.
How do these droplets occur?
When warm air touches a surface that is colder than itself, the moisture within the warm air escapes onto the colder surface.
And as we know, where there is water, shortly after there will be mold.
Various Forms of Condensation
This occurs when warm air touches a surface that is colder than itself. This is most common on the external walls of your container.
This occurs when warm air gets inside your home and touches the cold internal walls of your containers. However, in poorly ventilated homes this isn’t so common.
Passive and Mechanical Ventilation
So now that we know what can happen if your containers don’t have sufficient ventilation, let’s address how to ventilate your containers.
There are two overarching methodologies when it comes to ventilation. The first method being passive ventilation and the second method being mechanical ventilation.
Passive ventilation gives you the ability to ventilate your home without having to spend lots of money. Mechanical ventilation such as air conditioning requires a hefty energy bill, however, passive ventilation utilizes the earth’s natural elements to ventilate your home.
The cheapest, and most common, way to provide your containers with passive ventilation is to install either vents or a whirly bird onto your container. Placing vents onto your containers allows air to blow both in and out of your containers just by the wind.
This is most commonly referred to as cross ventilation. You place vents on the side of your container so that wind blows into them. Then install vents on the opposite side of your container. This allows air to blow in through vents on one side of your container and out of the vents on the other side of your container.
Another great way to passively ventilate your container is by designing it in such a way to utilize the wind to blow through your home.
We first saw this with shipping containers from Containers of Hope.
Containers of Hope is a shipping container home in San Jose, Costa Rica. It uses windows placed just beneath the roof to allow air to blow through the containers. These strategically placed windows keep the container cool on hot summer days and it also helps to reduce the humidity of the containers.
We have also seen a smart building design with Vissershok Primary School in South Africa, who decided to use shipping containers for classrooms.
Vissershok Primary School placed lots of small windows along both sides of the shipping container walls. This allows air to blow straight through the container and also removes stale air.
You can read more about keeping the containers cool at the Vissershok Primary School here.
In certain climates, such as very humid places like southern Brazil, passive ventilation is insufficient and mechanical ventilation is required.
In fact, in many countries like the US, Australia, New Zealand and the United Kingdom it is a building regulation standard to fit mechanical ventilation in kitchens and bathrooms. Depending on your country the minimum amount of extraction required is 15 liters per second in each room.
People normally attach an extractor fan (which is a type of exhaust-only mechanical ventilation) to meet this building regulation.
This fan allows the humidity to be extracted out of your home before it settles on a surface and turns into moisture and dampness. The fan should be attached as high as possible on the wall which is furthest away from the main source of air placement (either your door or window).
Supply Only Ventilation
The opposite of exhaust-only mechanical ventilation is supply-only mechanical ventilation. This is where, instead of the fan pushing stale air out of your home, the fan sucks fresh air into the home. Supply-only ventilation is very useful when your home has passive ventilation systems in place and you just need to increase this passive ventilation on hot days.
Your final, but most expensive option is to use a balanced ventilation system. This involves having fans to both push stale air out and suck fresh air in. The air can then be sent throughout your container using ducts.
In moisture prone areas such as bathrooms and kitchens, air can be extracted, and fresh air can be blown into other areas of your home such as the lounge and bedrooms.
Using a balanced ventilation system does allow you to very easily manage the moisture and humidity levels in your home.
Although not a mechanical ventilation device, a dehumidifier can help stop many of the problems caused by bad ventilation. A dehumidifier reduces the level of humidity in the air and thus can reduce the water content and stop condensation from corroding your containers!
They can be purchased as small stand-alone appliances which can be moved room to room. You can also buy entire home solutions which have ducts fed throughout the container.
One issue which we haven’t discussed so far is the importance of ensuring your foundation is ventilated. This is known as crawl space ventilation.
Not all foundations can be ventilated. For instance, if you have a slab foundation you won’t physically be able to ventilate it. However, if you have a concrete pier foundation, or any other type of raised foundation, then you need to ensure you have sufficient air flow underneath your containers.
Failure to ventilate your foundation can bring back that dreaded condensation which can cause your foundation some serious problem such as mold and rot. In addition, if your shipping container floor hasn’t been insulated, you can experience even more problems such as moisture rising up from underneath the containers into your flooring.
The most common way to stop moisture and allow ventilation underneath your foundation is to use vents.
© Larry Wade
Many areas stipulate through their building code that you must use vents to provide your foundation with air flow. These vents are typically fit with a wire mesh screen which keeps pests and insects out of your crawl space.
Vented crawl spaces work well in cold climates. In humid climates using a vented crawl space can actually do more damage than good because the external air is more humid than the air already in the crawl space.
In humid climates it would be better to seal off the airflow to your crawl space completely and use a dehumidifier.
Let us know how you chose to ventilate your shipping container building in the comments below!