How to Insulate a Shipping Container – DIY – (Inside and Outside)

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Are you looking for a way to save money on your power bill and keep cool/warm? If so, insulating your shipping container is a great idea. Shipping containers are incredibly energy efficient, but they’re also designed to keep large amounts of air out in order to prevent corrosion. This means that the heat inside the container can escape very quickly and it’s easy for outside air to come inside. With some insulation, this problem can be solved!

Today we’re going to have a deeper look at how to insulate a shipping container from the inside as well as the outside yourself. We will look at the different types of insulation available, inside vs outside insulation, what you’ll need to get started, and a step by step guide on how to do it.

What Materials You’ll Need to Insulate a Shipping Container

Much like any other tutorial you follow, there are a couple of things you’re going to need before starting. The following items are some of the things that will help you when insulating the container using closed-foam boards for the insulation material:

How to Insulate a Shipping Container

Inside Insulation

First we’ll take a look at insulating a shipping container from the inside because it is the more popular choice among container homeowners. We’ll also link to a couple of YouTube videos that we thought explained the process well.

When installing insulation inside, you want to do it in this order:

  1. Floors first
  2. Ceiling second
  3. Walls are last

Ok, now that we’ve got that out of the way, let’s get to it.

Step 1: Choose the Type of Insulation You’re Going to Use

There are numerous forms of insulation that you can choose from and you will need to choose the one that works the best for your needs. Closed-cell spray foam is one of the best methods you can choose for insulating a shipping container, and that’s the one we recommend using if your budget allows.

It eliminates condensation and has a much higher R-value than open-cell foam. The higher R-value means the unit will be much better at withstanding heat and it will also keep air and water from entering the container. Unfortunately, it is one of the more expensive types of insulation, but worth it if you are looking to keep the container for years to come. Right now it’s around $2 – 2.50/sq. ft. for closed-cell foam insulation.

However, spray foam insulation isn’t really a DIY method, and one you’ll definitely want to hire somebody to do for you. A good alternative to closed-cell spray foam is closed-cell foam boards. While there will be a small gap between the wall of the container and the insulation, if you combine this method with proper venting of your container, condensation shouldn’t be an issue.

Any time you’re doing insulation against the metal, you always want to use closed-foam insulation because the metal is going to get extremely hot in the summer, mix with the cold air, and cause condensation. Same thing goes for in the winter but in reverse. Closed foam does the best at mitigating this in my opinion, with spray foam at the top of the list.

Step 2: Clean The Inside Of The Shipping Container

Before doing anything, it is important to clean the inside of the container. Depending on how long it’s been since the container has been used, it might be corroded or dirty on the inside. Using a simple cleaning detergent, you can wipe the sides, floor, and ceiling of the container or have it professionally cleaned or sterilized before you proceed with the insulation.

dirty shipping container home that needs cleaned

Step 3: Decide How Much Insulation You Need

Once your container is cleaned and ready to go, you need to measure the container in order to determine how many foam boards you’re going to need.

Ideally, you want to insulate the walls, floor, and ceiling, but if that’s not in the budget, then just stick with the ceiling and walls. For best results though, do all three.

The main thing to keep in mind is that you want to maximize each insulation sheet as much as possible because it is EXPENSIVE! So, you want to leave as little scraps as possible when cutting the boards.

When measuring the container, you want to get the foam boards pretty tight in there, but give it a little bit of play as shown in the image below.

guy installing closed-foam board on the floor of a container

Step 4: Cut the Insulation to Size

Next, you want to cut each sheet to size based on your measurements from the previous step. Use your level and marker to mark off each cut so that you can be as accurate as possible. Again, this stuff is expensive, so you don’t want to be wasting it with lazy cuts.

guy measuring the insulation board

Note: When installing insulation, you want to start with the floor and ceiling first and then move onto the walls afterwards. This will make for a tighter fit.

Pro Tip: You want to use Great Stuff Window and Door Foam Sealant instead of the regular Great Stuff sealant so that it doesn’t push and bend the foam boards.

Step 5: Glue the Back of the Boards

gluing the back of the foam boards

After you’ve cut out the insulation boards, it’s time to install them! In order for the closed-foam insulation boards to stay in place, you need to glue them to the sides/ceiling of the container. We recommend using the Loctite PL Premium Polyurethane Construction Adhesive.

Note: You do not need to glue the back of the floor boards because they will naturally stay in place.

Step 6: Install the Closed Cell Foam Insulation Sheets

It’s finally time to install the insulation! When installing the boards, make sure to get as close to the sides of the container as possible. Once you’re ready to install the wall insulation, you want to spray the foam sealant before you place each wall board.

fill gaps in the container walls with spray foam
fill the gaps as you place the boards

Make sure the boards slide into place so that the spray foam is able to expand behind the boards and cover any gaps.

When you’re putting in the ceiling foam, the glue should be enough to hold it into place, but if you want to be extra safe, you can use wooden boards to keep them tight to the ceiling until they dry.

boards to hold ceiling foam in place
wooden support boards used to keep the ceiling foam in place while it dries

Step 7: Ensure the Container is Fully Insulated

Once all of the insulation is in place, you’ll want to do a walk-through and make sure no spots were missed. If you see any cracks, make sure to fill them in with the foam sealant to avoid issues down the road.

For each seem, you want to tape them with the Extreme Weather HVAC Foil Tape to ensure the container is fully insulated.

Exterior Insulation

Interior vs Exterior Insulation: How They Differ

You can choose whether you want to insulate the inside or the outside of your shipping container. Interior insulation is the most common option due to it being more resistant to the elements and having the added protection of the container materials. However, it can also reduce some of the space you have available on the inside.

The other alternative is to insulate the outside of the container. While the external part of the container can be insulated successfully, it requires a lot more work.

Interior insulation is the most common form of insulation. Most shipping container homeowners I know have chosen to insulate the interior and not the exterior.

Types of Insulation Materials for Shipping Container Homes

Closed-cell polyurethane insulation might be the best method of insulation. However, it is far from the cheapest. Insulating your container will depend on your budget and what you plan on using the container for. When using the shipping container as a home, the closed-cell polyurethane has the highest R-value. But, if it’s going to be used as an office, cabin, or workshop, closed-cell spray foam may not be necessary. Here are some of the additional options to consider:

Expanded Foam Insulation

One of the main alternatives to spray foam is the expanded foam insulation. Expanded foam insulation is similar to spray foam insulation, but it is already sprayed. These insulations are sold as pre-fabricated sheets that vary in length and size. However, they are much easier to use than spray foam due to be measurable and easy to cut to the correct size. There are numerous different versions of expanded foam insulation you can consider:

  • Open Cell Polyurethane: This is one of the other alternatives to consider, but can create pockets of air in the foam.
  • Polyisocyanurate: Polyisocyanurate has many of the same properties as polyurethane. However, it is more thermally resistant.
  • Extruded Polystyrene Foam (EPS): EPS is perfect for those looking for something affordable and it is made from small plastic beads for the best insulation possible.
  • Expanded Polystyrene Foam (XPS): If plastic is not enough in bead form, the melted plastic from XPS is also formed into sheets that are easy to use.

All of these foam insulations can work for your shipping container. However, closed-cell polyurethane is one of the best options on the market today. It might be slightly more expensive, but should keep the heat out, while resisting most of the elements.

Insulating With a Blanket

Blanket insulation is one of the most useful and affordable methods you can use for insulating your home shipping container. These forms of insulation are easy to set up and pre-cut. You can buy these blankets in large squares and cut them to size on your own. Here are common ways of using blanket insulation:

  • Fiberglass: Fiberglass is one of the top options to consider. However, it is a delicate material, which is known for irritating the eyes and skin. You might need an expert to assist you with the insulation.
  • Mineral Wool: Wool is another great alternative and while it might not be water-resistant, it has excellent heat retention.
  • Natural Fibers: Cotton is another alternative you can consider. However, it is slightly more expensive, with decent heat retention.
  • Plastic: Plastic is one of the cheapest options on the market today. However, it is not as good as insulating as the others.

These methods of insulation can also be referred to as batt and the R-value will vary depending on the thickness of the insulation. For 3.5-inch thick insulation, the R-value is 13. However, when it comes to 6-inches of insulation, the R-value can be 19.

Denim Insulation

If you are not concerned about using a renewable material, you can consider using recycled jeans. This is one of the more expensive methods of insulation. However, when done correctly, it has an average R-value of around 3.5.

While denim is a great DIY method of insulation, it does come with a few downsides. Some of these downsides include the lack of being fire retardant. Most of the other methods are fire retardant, and denim cannot wick away moisture. It is not recommended that you use denim for a home shipping container.

Cork Insulation

Cork is one of the top options when you need a biodegradable method of insulation. Cork trees do not need to be cut down for someone to harvest the cork from the tree. Aside from having, an average R-value of 3, cork has one added benefit in that it will also keep your container protected from noise. The downside is that cork is one of the more expensive materials.

inside container home
Source: Corklink

5 Factors To Consider Before Insulating Your Shipping Container

By now, you should understand exactly how to insulate your shipping container. However, there are a few important things we would like to note. The factors can make life so much easier for you and ensure that you get the best value for your money. Here are some of the most important considerations to keep in mind:

Climate Of The Area

One of the most important things to keep in mind is the climate of the surrounding area. Since you will be using the insulation to make the container livable or more sustainable, your level of insulation will depend on the surrounding environment. In extreme conditions, you might prefer more insulation. It is important that you can spend a day inside the container with the right climate if it is to be used for a shipping container home.

Vapor Barrier

You will need to look at the vapor barrier when it comes to keeping the container sustainable in the long run. The vapor barrier will mitigate the effects of moisture being stuck to the container materials. Since containers tend to “sweat”, you will be using the vapor barrier to prevent rust.

Heat Or Cooling

One of the main decisions you will need to make is whether you want the container to be heated or cooled. It will depend on the reason you are insulating the container, but the thickness and type of insulation will greatly vary depending on what you choose.

Layout

The insulation process is very important when it comes to the layout. The layout should be kept in mind to ensure that you leave enough space for anything you would like to place in the unit. We recommend planning the layout.

Eco-Friendly Materials

If at all possible, you would want to use eco-friendly materials to ensure you have sustainable living quarters. Oftentimes, you might need to patch up the insulation and when you use something eco-friendly it is much easier. Natural materials are always better to use in almost every situation you find yourself.

Frequently Asked Questions

With most of the information for insulating your shipping container now out there, you might still have a couple more questions. There are numerous questions we found around the web. Many of these questions could be what you might be wondering about. Here are some of the most prominent questions about shipping container insulation.

What Is Shipping Container Insulation?

Shipping container insulation refers to the methods you can use to insulate a shipping container. The insulated containers can serve multiple purposes, which include a cooling room or even a living area for yourself.

What is Shipping Container Condensation?

Shipping container condensation occurs once the walls become cooler thane the dew point. It is also commonly referred to as sweat and you will find moisture along the sides of the container. One of the risks to condensation is that it can spur on rust.

What Affects the Amount of Condensation in a Shipping Container?

There are numerous things you need to keep in mind when fighting condensation. One of these issues is the temperature and steep temperature drops. Moisture in the air can also have an effect on condensation.

What Is The Best Shipping Container Home Insulation?

The best shipping container insulation is PU spray foam. It has the highest R-value and will ensure that the container remains insulted for a longer period.

Final Thoughts

How to insulate a shipping container is not as hard as it seems and when you have the right equipment, you can easily get to work. There are tons of methods and many of these can be done by the individual in the comfort of their home. However, you might want to consider having expert advice.

We hope that you have enjoyed this article and the basic tutorial and would love to read some of your thoughts in the comment section below.

Ryan Stetson

Ryan Stetson

Currently own two 20' and 40' containers converted into an office/workshop. Having worked in the shipping industry for 6 years, my goal is to share my personal experiences as well as connect potential container buyers with suppliers around the US.

Ryan Stetson

Ryan Stetson

Currently own two 20' and 40' containers converted into an office/workshop. Having worked in the shipping industry for 6 years, my goal is to share my personal experiences as well as connect potential container buyers with suppliers around the US.

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