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How to Insulate a Shipping Container?

13 June 2024

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Tips & GuidesConversions
inside of an insulated shipping container

Gone are the days of shipping containers being solely used for their traditional purpose of transporting items. Nowadays, these sturdy steel boxes are used for much more than storage. People are turning them into trendy pop-up venues, cozy home offices, and even comfortable living spaces

Because of these new uses, it’s becoming increasingly important to insulate shipping containers, especially if they’re being used as a place to live or work. Proper insulation helps make sure that the inside of the container stays comfortable, no matter the weather outside. It’s important to know about the different types of insulation available and choose the right one for your needs.

Do shipping containers need to be insulated?

The short answer is – it depends on what you’re using your container for.

Shipping containers typically don’t need additional insulation when they’re used just for transporting goods, as they are designed to be durable and withstand various weather conditions during transit. The exception being sensitive cargo that requires temperature control, such as perishable food items or certain chemicals. Often, refrigerated containers, known as “reefers,” or chemical store containers are used to maintain these specific conditions rather than insulating the containers. 

However, if you intend to use your shipping container for a conversion project, insulating it is usually necessary. Insulation helps keep the inside temperature comfortable and saves on energy costs. Whether the container is a home, office, or shop, insulation prevents extreme temperatures. It also reduces condensation in your shipping container, which helps stop mould and rust from damaging the container.

Condensation

Whether you’re using your container to ship sensitive goods or as a living space, insulation is essential for avoiding condensation. Unprotected metal shipping containers experience condensation when warm air meets the cool metal. This can result in water vapour getting through, causing mould, rust and corrosion.

Thermal properties

Metal is an excellent conductor of heat and cold. But this means your container can experience extreme environmental temperature changes without insulation. For example, in winter it will feel much colder and the summer months will make the container really hot.

Living spaces

If you’ve chosen to create a container home or living space, insulation can prevent condensation and regulate temperature. It can also help you save energy and money as you won’t need to use your heating or air conditioning as much.

How to insulate a shipping container?

Now that you know when a shipping container might need insulation, you’ll also need to know how to actually insulate a shipping container. From setting up the initial framework to applying the final touches, here’s what you need to know to ensure your container is properly insulated for any use.

Step 1: Choose your insulation

Consider which type of insulation will best meet your needs by evaluating factors like thermal performance, budget, availability, and ease of installation, especially if you plan to do the work yourself.

Step 2: Clean the container

Before you do anything in your container, you must thoroughly clean and repair it, if required. You’ll need to remove dirt, debris, and rust to ensure your insulation works as efficiently as possible. 

Step 3: Determine how much insulation you need

Measure the inside of your container to see how much insulation you need. Ideally, you should insulate the walls, floor, and ceiling for maximum efficiency. However, if that’s not feasible, the walls and ceiling will do. 

Step 4: Cut the insulation (if required)

If you’re using insulation board or blanket insulation, you need to cut it to size accurately so that it fits your container. You don’t want gaps that can decrease the efficiency of your insulation, so be sure to take accurate measurements and make precise cuts.

Step 5: Install the insulation

Insulation should be installed as per the manufacturer’s guidelines on your chosen insulation material, ensuring it’s effectively providing thermal and sound insulation. Be sure to pay attention to any fixtures, electrical wires or outlets during the installation process.

Step 6: Seal gaps & joints

Once you’ve installed the bulk of your insulation, check thoroughly for gaps or joints where air could get in or out. Look particularly at the corners, edges and connecting points of your insulating material. You’ll then need to seal any gaps or joints with a compatible material – this could be caulk, sealant or expanding spray foam. 

Step 7: Insulate the doors & windows

Your doors and windows are the most common places for insulation to lose effectiveness. Weatherstripping or insulation tape can prevent drafts and maintain insulation effectiveness. Without doing this, you’re at risk of heat loss, air infiltration, and unregulated temperatures. 

Step 8: Add interior finishes

After insulating, you can add interior finishes like wall panels or drywall to cover the insulation and provide a better finish. This can even add an extra layer of insulation in some cases. Be mindful of your insulation and try to avoid any damage that could affect thermal efficiency. 

Step 9: Insulate the exterior (Optional)

If you’ve chosen to use external insulation, now’s the time to do it. This additional layer of insulation can help minimise thermal bridging and heat transfer. In turn, this improves energy efficiency and thermal performance. 

Step 10: Inspect the insulation

Your last step is to thoroughly check your work to ensure the shipping container is fully insulated, addressing any issues as you go. Look for gaps, cracks or areas where insulation has been damaged or moved. While this is an essential step once you’ve completed the insulation, you should also do it periodically to check for damage, wear, or deterioration. 

Types of insulation for shipping containers

To help you make an informed decision, it’s a good idea to familiarise yourself with all insulation types and their benefits. The best way to insulate a shipping container will depend on your requirements and the outcome you want to achieve.

Blanket insulation

This is the most commonly used and often cheapest type of insulation available. It consists of flexible fibres made from a variety of different materials. Fibreglass is the most common and is made from superheated sand or recycled glass. Other options include sheep wool, cotton or denim insulation. 

Batt insulation

Blanket insulation is available in batt form, which means it is pre-cut in flat pieces. This is typically used for insulating containers and living spaces because it’s flexible and easy to install in walls and ceilings. 

Rockwool or mineral wool insulation

Rockwool or mineral wool insulation is great for insulating areas that need even greater flexibility, for example around wires or pipes. This insulation offers fire resistance, moisture resistance, and high R-values, making it an effective choice for containers.

Loose-fill insulation

This type of insulation is formed when small particles join together and conform to a space. It’s good for adding insulation to irregularly shaped areas or around obstructions. The different types of loose-fill insulation include cellulose, vermiculite, perlite, and loose-fill fibreglass. 

Styrofoam insulation

You’ve likely heard of Styrofoam already, it’s a brand of closed-cell extruded polystyrene foam (XPS) that’s both lightweight and durable. It’s ideal for basic storage containers as it’s easy to install and cost-effective. Styrofoam also offers some soundproofing, making it a great choice for a garden office.  

Expanded foam insulation

expanded foam insulation

There are several different types of expanding foam insulation that can be used to insulate a shipping container. Most are available in spray form. The different types include:

  • Open Cell Polyurethane Foam – filled with air to give a spongy texture
  • Closed Cell Polyurethane Foam – filled with gas for better heat conduction and improved R-value
  • Extruded Polystyrene Foam – small plastic beads fused together
  • Expanded Polystyrene Foam – molten material pressed into closed-cell foam sheets
  • Polyisocyanurate (polyiso) – similar to polyurethane but more rigid

Expanding foam insulation is particularly useful for tricky areas where cutting insulation boards is not an option. For example, filling small wall cavities, sealing gaps or preventing air intrusion around windows.

Spray foam insulation

Expanded foam insulation is mainly available as spray foam, with the two terms often used interchangeably. Spray foam is an easy and effective way to maintain a consistent temperature and humidity in your shipping container. It can be applied both internally and externally and also acts as a sound barrier.

Ply wood insulation

Ply lined insulation is a popular choice for shipping containers, especially when converting them into habitable or office spaces. This method involves lining the interior walls of the container with sheets of plywood over a layer of insulation material such as fiberglass or foam.

Plywood not only adds an additional layer of thermal protection but also provides a smooth, finished look that can easily be painted or decorated. Ply lining also acts as a barrier that improves the container’s acoustic properties, making the space quieter and more private.

Aluminium insulation

Aluminium insulation, often used in shipping containers, involves using aluminium sheets as a radiant barrier along with other insulation materials. Typically, aluminium sheets are combined with materials like polyethylene bubble film or fiberglass to enhance its insulative capabilities. This combination not only provides excellent thermal insulation but also contributes to moisture resistance, preventing condensation inside the container.

Aluminium insulation is lightweight, easy to install, and a cost-effective solution for modifying shipping containers for various uses, from storage spaces to fully functional living areas.

Need professional help to insulate your shipping container? Get in touch with our team today to learn all about how we can help for all your insulation needs!

Other insulation options

Any material with the capability to insulate can be used as an insulator for your shipping container. If you’re a keen recycler, you can use repurposed materials in your conversion or find a cheaper way to keep your goods protected in transit. 

Living roof insulation

A living roof can act as insulation for the shipping container. In warm weather, living roofs can reduce indoor temperatures by up to 8%. While this is good, it’s worth noting that a living roof cannot be used as a complete alternative to insulation. It can, however, be used alongside insulation to improve efficiency.

Eco-friendly insulation

Many of us are seeking environmentally friendly alternatives and insulation is no different. Opt for wool, cotton or recycled denim insulation if you’re looking for something sustainable that also provides good thermal resistance.

Choosing the right insulation for your shipping container

Insulating your shipping container isn’t as simple as just picking up some board insulation. There are several factors to consider. Your choice of insulation will determine the level of thermal regulation, acoustic dampening, the longevity of your shipping container, as well as it’s performance. 

Climate

Your first consideration will be the climate and how hot or cold your container is likely to get. 

Hot climates

If you’re lucky enough to live somewhere warm, your primary concern will be keeping heat out of your container to maintain a comfortable temperature inside. Consider insulation with reflective or radiant barriers, like aluminium foil, to reflect heat away from the space. 

Cold climates

In contrast, containers located in cold places will need insulation that keeps the warmth inside. Look for insulation with a high R-value (a measure of thermal resistance), like foam insulation or rigid foam board. 

Interested in learning more about protecting your container in cold climates? Read all about how to protect your shipping container from frost damage in our detailed guide: 4 Tips To Prevent Frost Damage To Shipping Containers

Humid climates

Containers placed in humid locations need moisture-resistant insulation to prevent dampness, mould, and corrosion. This is important whether you’re using a container as a living space or storage. Spray foam is a good option and most commonly used in humid climates.

Variable climates

Many geographical locations experience all the seasons. For storage containers placed in variable climates, you’ll need a combination of insulation. For example, you might want insulation with a high R-value and reflective outer to both retain and reflect heat.

Budget

Your budget will play a significant role in deciding which insulation you choose. Consider both the immediate and long-term costs surrounding energy efficiency and maintenance. 

Material costs

Different types of insulation will vary in price. For example, blanket insulation is often the cheapest option because it’s easier to install. Rigid foam boards and spray foams are usually more expensive due to their complex installation. 

Installation costs

If you can’t install your insulation yourself, you’ll need to factor in the cost of hiring a professional. Spray foam insulation, for example, requires special equipment and skilled labour. 

Maintenance costs

Depending on your choice of insulation, you may need to maintain or replace it more frequently than others. For example, insulation without moisture-resistance properties might need replacing sooner than an alternative. It’s worth considering whether a more efficient and expensive material might offer more long-term cost benefits.

Intended use

Your container usage will also play a role in deciding which insulation to choose. Considering the intended use will help ensure that the insulation you select not only enhances comfort but also meets the specific needs of your project.

Residential use

If your container is going to be a living space, you’ll need to use insulation that can maintain a comfortable temperature and control moisture. Your container home insulation might also be subject to local building regulations. It’s worth familiarising yourself with those before you choose.

Commercial use or office space

Like residential use, your office should have insulation that keeps it comfortably warm enough to work in. You might also want to consider something that offers greater soundproofing or noise reduction alongside temperature regulation.

Storage

If you’re using your shipping container for storage, you could use cheaper insulation with fewer properties. This is because your main concern will be protecting your items from humidity and moisture as you won’t need to worry about creating a comfortable temperature for living.

Agricultural use

From housing animals to cultivating plants (in a “growtainer”), shipping containers offer a variety of agricultural uses. You’ll need to choose insulation that maintains a consistent humidity and temperature level. Something moisture-resistant and eco-friendly would also be beneficial. 

Interior vs exterior insulation

When it comes to insulating your shipping container, you can choose from interior and exterior insulation, or both. Your choice will depend on your needs, budget, and intended use.

Interior insulation

internal insulation for shipping container

The most common method of insulation is interior application. This is because it tends to be more resistant to the elements with the added protection of the container shell. It’s especially beneficial for containers located in places susceptible to damage. 

Advantages:

  • Cheaper
  • Easy to install
  • Easy to replace

Disadvantages:

  • Reduces internal space of the container
  • Installation can be complex if the container has been modified
  • Poor installation can lead to condensation

Exterior insulation

Some containers benefit from exterior insulation alone, or in addition to interior insulation. Insulating a shipping container from the outside will usually include a two-layer system. One layer insulates the container and another protects it from the elements. 

Advantages:

  • Doesn’t affect internal living space
  • Prevents thermal bridging
  • Prevents condensation

Disadvantages:

  • More expensive
  • More complex to install
  • Requires cladding the container or a similar layer to protect from weather and UV damage
  • Can alter the look of the container

How much does it cost to insulate a shipping container in the UK?

It’s difficult to put an exact price on how much it costs to insulate a shipping container as it depends on several different factors:

  • Container size
  • Type of insulation
  • How much of the container is being insulated
  • Labour costs

Usually, blanket insulation is the cheapest option with costs between £1 and £3 per square foot. Rigid foam board is next at £1.5 to £5 depending on the brand and thickness. Spray foam insulation is usually the most expensive option, with prices between £3 and £6 including labour. 

The bottom line

Whether you’ve already got your container and you’re ready to insulate, or you’re planning a home project and want to be fully informed, our insulation guide should have helped you make a few decisions. If you’re still looking for the perfect container for your project, check out our available shipping containers

Looking for a completely custom solution?

We have a wide range of base containers that can be customised to your needs, however we realise that sometimes you need something completely ‘Outside the box’.

Contact us and one of our experts will be in touch to help design the container of your dreams

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