Are Shipping Containers Waterproof and Airtight?

What Makes a Shipping Container Waterproof?

Shipping containers are designed to keep goods safe from the elements. However, their waterproofness can vary depending on their design, age, condition, and maintenance history.

Key Factors That Influence Waterproofing:

• Design: Corrugated steel walls, rubber door seals, and welded seams are all intended to prevent water ingress.
• Condition: Older or heavily used containers may have rust, dents, or weakened seals, making them less waterproof.
• Environment: Coastal, humid, or heavy rainfall areas can accelerate wear and increase the risk of leaks.
• Maintenance: Regular inspections, applying protective coatings, and timely repairs are essential to maintain waterproof performance.

New containers will generally be more waterproof than used units, but with careful maintenance, used containers can also provide excellent protection.

Are Shipping Containers Completely Airtight?

Shipping containers are built to be highly secure and weather-resistant, but they are not entirely airtight. Standard containers feature small ventilation openings designed to allow minimal airflow. This helps prevent condensation inside the unit during storage or transit.

Modifications, such as installing additional seals or adjusting ventilation systems, can enhance a container's airtightness for specialist uses, such as chemical storage or sensitive goods.

Factors Affecting Airtightness:

• Door Seals: Heavy-duty gaskets create a good seal but are not fully airtight by default.
• Ventilation: Small factory-fitted vents allow airflow to prevent moisture buildup inside the container.
• Modifications: New doors, windows, or utility connections can impact airtightness if not properly sealed.
• Structural Condition: Rust, dents, or poor welding at seams can allow air and moisture infiltration over time.

Improving Waterproofing and Airtightness

If you plan to use your shipping container for storage, living spaces, or sensitive goods, it's worth taking extra steps to enhance its protection:

1. Inspect thoroughly: Check for rust, dents, weakened door seals, and any damage that could allow leaks.
2. Repair promptly: Seal cracks, replace damaged seals, and repaint using marine-grade protective coatings.
3. Apply waterproof coatings: A rubberised roof membrane and protective side coatings can significantly improve waterproofing.
4. Seal modifications: To maintain the container's integrity, windows, doors, and vents should be installed with airtight and watertight materials.
5. Regular maintenance: Inspect your container seasonally to catch any early signs of wear or damage.

Waterproof vs. Watertight: What's the Difference?

While often used interchangeably, "waterproof" and "watertight" mean slightly different things:

• Waterproof: Resists water entry even in extreme conditions like submersion.
• Watertight: Resists water entry during normal conditions like rain and splashing waves.

Most shipping containers are designed to be watertight under typical conditions, but not necessarily waterproof against extreme flooding unless specially modified.

FAQs About Shipping Containers

Can a shipping container survive a flood? 

Shipping containers are highly durable and can resist short-term flooding if properly maintained. Elevation and anchoring are recommended for flood-prone areas.

Can water get inside a shipping container?

Yes, if seals are damaged, rust forms, or maintenance is neglected. Regular inspections and protective coatings help prevent leaks.

Can I make a container completely airtight?

While containers are not naturally 100% airtight, you can enhance airtightness with extra sealing, welding, and specialised ventilation systems, depending on your requirements.

Need a Waterproof or Airtight Container?

At Shipping Containers of Felixstowe, we offer high-quality new and used containers that are secure, durable, and ready for your project. We also advise on modifications to meet your waterproofing and airtightness needs.