Are you planning on placing a tiny home on your property, or do you want to live off the grid? Shipping container homes offer a sustainable and cost-effective housing solution, but they can potentially come with a number of challenges. 

Condensation inside the container is risky and can potentially lead to structural damage, health issues, and reduced comfort, so it’s important to know how to prevent condensation.

This article explores shipping container condensation, insulation, and ventilation in shipping containers, their impacts, and how you can identify whether your shipping container home can do the job. After all, a shipping container may be your new home.

What is Condensation?

When warm, moist air contacts a cooler surface, this causes something known as condensation. In shipping container homes, this can manifest as water droplets on the interior walls and ceiling, also called "container rain." This moisture can lead to mould growth, corrosion, and damage to shipping container insulation and interior finishes. 

Let’s take a look at what can cause condensation:

1. Temperature Spikes: The weather can change quickly (especially in Melbourne). Warm interiors during cool nights can result in high humidity and form condensation.
2. Excess Moisture: Cooking, showering, and even breathing release moisture into the air. Unsealed openings or inadequate ventilation can allow humid air to enter the container home, and you don’t want this happening!
3. Container Construction: Shipping containers are made of metal (which is an excellent conductor of heat and cold), but they can heighten temperature differences. This increases the chances of condensation forming on interior surfaces.
4. Type of Goods: Wood, paper, cardboard, books, and mattresses can store moisture inside them, and even too much open space can increase your chances of moisture build-up.

What are some of the impacts of condensation on container homes? 

Condensation can cause:

• Health Issues: Mould and mildew growth can trigger respiratory problems and allergies.
• Structural Damage: If the container’s metal frame corrodes, this can damage the wood or drywall finishes.
• Insulation Issues: Compromised insulation can reduce energy efficiency and increase heating or cooling costs.

How Can You Stop Condensation in Shipping Containers?

Do you want to make your container home comfortable and durable? Here are some things you should consider.

1. Ventilation

Proper air circulation helps to manage indoor humidity levels, such as evening out the interior and exterior temperature of the container home.

• Natural Ventilation: You can install windows and vents to facilitate airflow. Fresh air can enter, and moist air can escape, stabilising humidity levels. 
• Mechanical Ventilation: Use exhaust fans in high-moisture areas like kitchens and bathrooms. For example, container floor insulation supports consistent air exchange.

Although shipping container homes are made to be airtight, they can still be a challenge when converted into homes. This process requires special considerations during the design and construction phases, which Sonic Steel is an expert in.

Although airtightness supports energy efficiency, it also leads to a lack of ventilation–especially when exterior humidity levels fluctuate throughout the year, and interior humidity pushes past comfort levels. A ventilation system needs to adapt well to temperature and humidity changes throughout the seasons.

Do you want to ensure your shipping container home is energy-efficient with proper insulation? One of a kind, Sonic Steel’s ventilation system balances airtightness with fresh air exchange. Pairing HRVs with the VenSulation system reduces energy cost and improves indoor climate control.

2. Insulation

Quality insulation helps regulate interior temperatures and prevents condensation from forming on fully welded corrugated metal walls. Moisture must not come into contact with the internal metal surface.

• Polyurethane: Polyurethane (PUR) panels (not spray foam or EPS) work as a vapour barrier between the container wall and the interior space, increasing thermal and sound insulation while eliminating the internal metal surface’s exposure to moisture.
• Block-Moulded Polyurethane Panels: Manufactured in Australia by block-moulding and stored to cure for at least 30 days, these are precisely CNC cut to fit into the corrugations of container panels. This forms a barrier that eliminates air gaps, maintains a constant temperature, and prevents condensation. To top it off, these panels can accommodate electrical cables and plumbing pipes!

3. Dehumidifiers

Is your container home being lived in the long term and has access to electricity? Dehumidifiers reduce excess moisture in the air, keeping humidity levels in check.

• Portable vs. Whole-House Systems: Portable units are suitable for smaller homes, while integrated systems work well in larger setups. 
• Placement: Dehumidifiers should be placed in areas prone to high humidity, such as bathrooms or basements. For example, you might use one to reduce the moisture content in wooden flooring.

4. Moisture-Resistant Finishes

Water-resistant materials for interior finishes are a great way to stop condensation.

• Paints and Coatings: Apply anti-condensation paints or waterproof coatings to walls and ceilings.
• Flooring: Put in place moisture-resistant flooring materials such as vinyl or sealed concrete. 

Not insulating a shipping container floor can account for up to 20% of heat loss and cooling energy (as well as deterring pests and offering high BAL ratings)! 

Sonic Steel insulates between the container's cross members/floor joints with polyester for its moisture resistance. The entire underside is then closed off by galvanised metal sheets to keep the polyester in place, ultimately creating airtightness of the floor structure. 

5. Seal Gaps and Cracks

Sealing your container home stops moisture outside from entering.

• Weatherproofing: Use weatherstripping around doors and windows. Seal seams and joints with high-quality caulk or silicone.
• Inspection: Regularly inspect for leaks or damage that could allow water ingress.

Sonic Steel uses a high-performance window system which is Australian-made and uses double-glazed windows with a Low-E coating, and a thermally-broken frame by ThermalHeart.

ThermalHeart windows incorporate a thermal insulator within the aluminium frame (typically a polyamide strip), which reduces heat transfer and also prevents condensation. 

In any case, it’s critical to keep doors and windows open as much as possible to let that fresh air through! 

Achieving airtightness requires a lot of attention to detail during construction. Sealing every joint, seam, and penetration requires expertise and specialised materials. If building your home shipping container sounds like too much stress to do alone, Sonic Steel can implement insulation for you. Contact us today or send through an online enquiry. 

Do you want to learn more? Have a read of why insulating your shipping container is essential! In any case, Sonic Steel has a range of building materials and methods to achieve the best home, whether off-grid or in your backyard.

Sonic Steel: Other Shipping Container Ventilation Systems

Some of the benefits of airtight shipping container homes include:

• Better indoor air quality and an overall healthier living environment. You don’t need to worry about pollen or dust mites getting their way in!
• Energy efficient, so heating and cooling costs won’t be as expensive as a traditional home. 
• Reduced noise pollution, meaning it blocks out external noises (such as loud traffic!)
• A foolproof design makes it more difficult for insects and rodents to get inside. 

What are some other ventilation systems Sonic Steel brings to container homes that other shipping container home businesses don’t? 

Heat Recovery Ventilator (HRV)

Sonic Steel uses natural cross ventilation with operable windows, and it has a Heat Recovery Ventilator (HRV) to control mechanical ventilation. This will retain up to 85% of thermal energy while bringing in fresh, filtered air in exchange for stagnant air. 

When it’s a cold winter night, you can keep warm with windows shut and still enjoy a space that is well-ventilated–all from just 8W of energy. Ultimately, HRV reduces the load on your air conditioning system, ensuring a healthy, comfortable living space and maintaining a happy humidity level. 

Air Conditioning

Sonic Steel uses Daikin’s split system A/C for reliable climate control, which everyone can be content with. This split system circulates internal air continuously to maintain the desired indoor temperature. There won’t be any cold spots in your shipping container!

Daikin’s split system also uses inverter technology, which adjusts the compressor speed based on cooling demand. If you want to learn more about Daikin, the Sonic Steel team can explain the benefits of container spaces in more detail.

Airtight Dampers

In any home (but a tiny home in particular), airtight spaces are good, but you want one that balances this airtightness with a steady temperature. 

Sonic Steel uses the Naber THERMOBOX to put a stop to backdraught throughout the kitchen exhaust. It works without electricity and uses air as an insulation medium: it’s genius. 

What does this system consist of? Three dampers are arranged behind the other, sealed by a magnet, and when closed, these flaps form two chambers that trap air (which is a poor heat conductor), reducing heat loss. Hot or cold air stays out, even in strong winds!

Odourless Toilet System

A big part of Sonic Steel’s mission is to give you a fresh, comfortable living environment, and this counts for toilet odour. Let’s look at some of our options for a superior bathroom experience!

The Panfan

Panfan features a sophisticated ventilation system that easily extracts odours directly from the toilet bowl and vents them outside so your bathroom stays fresh. It operates quietly, uses minimal energy, and effectively removes odours.

The Milu

For flushing systems, the Milu Odourless Toilet features an in-built fan that quietly extracts odours from the toilet and discharges them into the sewer–this stops all bad smells. The Milu also uses a hygienic, easy-to-clean rimless bowl with a powerful flush and a soft-closed seat and lid for convenience and comfort. 

Sonic Steel: Durable Container Homes in Australia

As a leading business in the shipping container industry for nearly a decade, Sonic Steel began as a repair and maintenance service provider before expanding into the shipping container modification and construction of unique, functional container homes. 

With a deep understanding of shipping container houses, we bring clients’ personalised design and living spaces to life. Whether you are looking to ship container homes in Victoria, NSW, SA, or across Australia, we value your personal experience and provide transparent, honest service for the duration of the project.

Start your journey today by reaching out to our friendly team! Call 0431 059 331 or email enquiry@sonicsteel.com.au to get in touch! Feel free to explore our shipping container DIY options.

With the Tiny Home Expos in Brisbane, Adelaide and Canberra in the coming months, we are offering FREE DELIVERY (*up to $5000) to each state the Expo is in, in exchange for using your project as a display at the show. Offer expires 8 weeks before each Expo and is limited to ONE project per Expo ONLY, so reach out to us now to secure your spot!