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 or not. 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 realise the importance of properly insulating your home, I hope you decided to insulate!
Climate, Climate, Climate!
When it comes to the methods used to insulate your home, the one thing to bear in mind throughout this entire post is: 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 vapour barrier.
Whereas, if you are in a very dry, hot, climate, you certainly won’t need much insulation and you should focus on designing your insulation around keeping your container cool (see the section below on design or read: How Do I Keep My Container Home Cool?).
When reviewing the methods of insulation below, keep this issue about climate differences in your mind and feel free to ask any questions in the comments below!
When it comes to the types of insulation you can use, you have five major options: you can use 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 vapour barrier of insulation- this 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 fit than most of the other insulation methods which we discuss later.
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; you can also spray it underneath your container to stop any moisture from the ground creeping into your containers.
Image From 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 the most DIY friendly type of insulation and like blanket insulation, it requires stud walls to fit. You can buy the panels at 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 whilst being moderately priced.
Blanket, or roll, insulation is DIY friendly and is the cheapest of the insulators discussed here. It requires stud walls to place the insulation in, but once the stud walls have been fitted the insulation can be placed in the gaps very quickly. The most common blanket insulation is mineral, and you probably know it as rock wool.
Image From Larry Wade
The only difficulty you will find with this type of insulate is fitting it; some types of blanket insulation are made from fibreglass so they need to be handled with care. If you are fitting this type of insulation make sure you wear the correct personal protective equipment (i.e. dusk mask, gloves, protective closing and safety glasses).
If cost is your primary concern I would choose this insulation, however if possible, I would again recommend using spray foam insulation so you can create a seamless vapour barrier.
As we discovered in our last blog post, Why Do People Live In Shipping Container Homes, the second most common reason people live in shipping containers is because 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 and some of our favourites include: wool, cotton, mud and a living roof.
Wool insulation is similar to the blanket insulation discussed above. However instead of using controversial materials such as fibreglass, it uses natural sheep wool which can be made for a fraction of the energy requirements used to make its synthetic counterpart.
Again like wool, cotton insulation is a type of blanket insulation; it is made out of recycled cotton clothes.
So what makes cotton so environmentally friendly? Well, it’s a natural, renewable resource which can be grown extremely quick. The only obvious downside to cotton insulation is, it costs double that of normal fibreglass insulation.
Creating a living roof isn’t a direct replacement for your insulation, but it can certainly be used to help reduce your indoor temperatures during the summer.
During the rainy seasons, a living roof offers no insulation benefits, however during warm summers indoor temperatures can be reduced by up to 8 percent. Not only that- how cool do they look!?
Much better than a traditional sloped roof I’m sure.
Mud, can be used as an insulator or it can be used to build entire houses on its own. Much similar to the living roof mentioned above, mud can be used in dry-hot climates to keep heat out.
This has traditionally been done for centuries in places like North India, where entire homes are cladded with mud.
With shipping containers, mud can be used on the containers roof and also on the containers walls. If you are using mud on the containers external walls you will need to use battens which will allow the mud to stick to the container.
Using mud is only recommended in places where rainfall is scare.
Your final option is to actually design your home in such a way that it cools/heats itself. The best example we have seen of this is Vissershok Primary School in South Africa.
Vissershok Primary School decided to extend their school by making stand-alone classrooms out of shipping containers.
During the summer external temperatures in South Africa can reach in excess of 86 Fahrenheit, so it was crucial that the containers were insulated properly to stop them heating up like a green house. The solution to this was to design the containers in such a way to use the natural environment to cool the containers down.
They built the classroom with a huge sloped roof which does two things: Firstly, it allows hot air to rise up and out of the container. Secondly, cold air blows in and gets pushed down by the roof into the classroom.
Another design used to help keep the containers cool was to place lots of small windows on both sides of the container. When the windows are open, it allows cool air to blow across the container taking the warm air out of the container.
One thing to bear in mind here is that you don’t 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 on the same section, for instance 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.
The best shipping containers use a variety of insulation methods which have been specifically chosen to best meet the needs of their local climate.