Before we look at the five methods you can use to insulate your shipping container home, the first question we need to address is whether you should insulate your container home. I can’t stress enough the importance of insulating your home. Although the option of not insulating might seem an attractive, cheaper alternative, in the long run it simply isn’t cost effective.
If you don’t insulate your container, not only will your home be either scorching hot or arctic cold, your home will also be susceptible to condensation, which can cause corrosion or mold.
Now you realize the importance of properly insulating your home, we hope you decided to insulate!
How your climate affects your insulation decision
When it comes to the methods used to insulate your home, the one thing to bear in mind is that it all depends on your climate!
For example, if you are in a very cold climate, you will need lots of insulation to keep your home warm and also, more importantly, to protect your containers against condensation. If this cold environment is also prone to lots of rain and is very moist, then you would need to use spray foam insulation to create a seamless vapor barrier.
If you are in a very dry, hot, climate, you certainly won’t need as much insulation and you should focus on designing your insulation around keeping your container cool (for more information, read How Do I Keep My Container Home Cool?).
Types of Shipping Container Insulation
When it comes to the types of insulation you can use, there are five major ‘types’: foam, blankets (rolls), insulation panels, Eco-friendly and finally, design (more about this later).
If your budget allows, I would choose to use spray foam insulation. Using spray foam insulation ensures you get a seamless vapor barrier of insulation, which helps to prevent against things like corrosion and mold.
Spray foam is by far the quickest method of insulation, and in most cases provides the highest R rating (the R rating is how well the insulating material can resist heat flow; the higher the number the greater the resistance). In addition, spray foam is incredibly flexible and can be sprayed into gaps of any size.
The only downside of using spray foam insulation is that it’s more expensive and a lot messier to use than most of the other insulation methods which we discuss.
For the spray foam, something similar to the DOW Froth Pak 600, would be ideal. This is a two-part mixture, and each inch of foam applied provides an R value of 7.5. If you aren’t looking for an industrial solution you can purchase hand operated spray foam such as Dow Great Stuff foam insulation. Whichever spray foam solution you choose, make sure it’s closed cell polyurethane foam.
Spray foam insulation can be applied on both the external and internal walls of your containers. It can also be sprayed underneath your container to stop any moisture from the ground creeping into your containers.
Image courtesy of Larry Wade
Once the foam has set, you can then decorate straight onto the foam with paint to finish off the external appearance of your containers.
Panel insulation is a very DIY friendly type of insulation and like blanket insulation, it is attached to studs. You can buy the panels in predefined sizes and simply fit them in between the gaps in your stud walling. Panel insulation is quicker to fit than blanket insulation; however, you normally find panel insulation is slightly more expensive.
One thing you should bear in mind, however, is that panel insulation has a high insulating value for its relatively small depth. Depending on the brand and specification, for every inch thickness they normally have an R value of 7.5. So, if you don’t want to spend a lot of money for foam insulation, panel insulation will allow you to keep the thickness of your insulation to a minimum while being moderately priced.
Blanket, or roll, insulation is DIY friendly and is the cheapest of the insulators discussed here. It must be attached to studs, but once the stud walls have been installed, the insulation can be placed in the gaps very quickly. The most common blanket insulation is rock wool.
Image courtesy of Larry Wade
The only difficulty you will find with this type of insulate is attaching it. Some types of blanket insulation are made from fiberglass so need to be handled with care. If you are using this type of insulation, make sure you wear the correct personal protective equipment (i.e. dusk mask, gloves, and safety glasses).
If cost is your primary concern, choose this insulation. However, if possible, we still recommend using spray foam insulation to create a seamless vapor barrier.
Previously, we discussed the question of Why Do People Live In Shipping Container Homes. A common reason people give is that they want to build homes in a sustainable, environmentally friendly manner.
So what better way to continue this theme than to use Eco-friendly insulation to insulate your home?
Over recent years more and more Eco-friendly insulation has become available. Some of our favorites include wool, cotton, mud, and a living roof.
Wool insulation is similar to the blanket insulation discussed above. Instead of using controversial materials such as fiberglass, it uses natural sheep wool, which can be made for a fraction of the energy requirements used to make its synthetic counterpart.
Like wool, cotton insulation is a type of blanket insulation made out of recycled cotton clothes.
What makes cotton so environmentally friendly? Well, it’s a natural, renewable resource which can be grown extremely quickly. The only obvious downside to cotton insulation is that it costs double that of normal fiberglass insulation.
A green or living roof is a garden of sorts on your roof, with various grasses and other plants. Soil and plants aren’t great insulators, but they can help to block solar radiation if you live in a warm climate. A green roof, therefore, isn’t really a replacement for insulation, but a supplement to it.
An additional benefit of green roofs is that they look cool! From the sky, your container will look like just another patch of ground.
Passive Heating and Cooling Design
Your final option is to actually design your home in such a way that it minimized the amount of energy needed to heat and cool it. A good example of this is Vissershok Primary School in South Africa.
Vissershok Primary School decided to extend their school by making classrooms out of shipping containers.
During the summer, external temperatures in South Africa can reach in excess of 86 F, so the school needed a solution to keep the kids from heating up like plants in a greenhouse. The solution to this was to design the containers to use the natural environment as a source of cooler air.
They built the classrooms with a huge sloped roof which allows hot air to rise up and out of the container, and cool intake air to enter into the classroom from below.
They placed lots of small windows on both sides of the container. When the windows are open, it allows cool air to blow across the interior spaces.
While these passive methods can be effective in more temperate climates, they often won’t be enough on their own. For instance, the coolest you’ll ever feel in a passive-designed container is if you were in the shade with a breeze blowing. If even that is too hot, a passive design isn’t going to be enough.
You have quite a few insulation options at your disposal, and what you choose is driven by factors like your climate, design, and budget. All choices have their pros and cons, but now you have a better understanding of what those are.
One thing to keep in mind is that you don’t necessarily have to use a certain type of insulation exclusively. For instance, you could use spray foam insulation for the container walls and roof, and then use rock wool underneath the container to keep the cost down. You can even combine insulation in the same area. For example, you could use rock wool on the underneath of the container and then spray an inch of foam over the rock wool to create an airtight seal. Whatever you do, make sure you understand the implications of condensation if you’re in a climate where it is a concern.
Let us know which type or types of insulation you used on your shipping container home.