How Should I Protect My Shipping Container Home from Rust?

All homes need to be protected from the elements. Wood rots; mortar between bricks or stone crumbles. Container homes are no different—they are at risk of rusting if they are not handled carefully.

Prevention

As with many things, prevention is the first—and best—step in solving a problem. Most shipping containers are made from COR-TEN steel, which is strong, durable, and resistant to corrosion. Cor-ten steel is also known as the “weathering steel.”

Cor-ten steel forms a protective layer of rust when exposed to air and water, providing corrosion protection for the steel. This layer requires a wet and dry cycle to develop; in predominantly wet climates, the necessary dryness is lacking, while dry climates miss the moisture needed for protection.

Cor-ten steel is commonly used in containers because manufacturers guarantee a 3-5 year corrosion-free period. While this might seem sufficient given the harsh conditions containers endure at sea, it's important to remember that homes should ideally last longer, and any container home must account for various environmental factors.

Design

To ensure your container home is well-designed, it’s crucial to minimize the containers’ exposure to weather elements and consider your site’s physical conditions. For example, if prevailing winds come from the west, incorporate additional plantings or shelters on that side to manage water exposure.

Utilizing shade can help keep your home cooler in summer, enhancing occupant comfort and reducing condensation. Excess moisture can lead to rust, mold, and damage to insulation. Proper ventilation is essential for maintaining a cooler and drier environment within the container.

If you’re building in coastal areas, be aware that salt-laden air can accelerate corrosion in Cor-ten steel. It’s often advised not to use shipping containers for homes within three miles of the shoreline.

Most locations will require a foundation for your home; avoid placing containers directly on a slab. A full basement or crawl space is preferable, as it provides access to the underside of the container.

During the design phase, ensure that any areas prone to water accumulation are either eliminated or adequately covered. Joints between containers can become corrosion traps, so it’s important to address any potential spots where debris, such as leaves, might collect.

Insulation

When planning insulation for container homes, it’s important to strike a balance, as excessive insulation can reduce interior space. In cold climates, proper insulation is essential to maintain warmth and prevent condensation. Here are several insulation options to consider:

Spray Foam: This creates a vapor barrier that helps reduce condensation and mold. It can be applied to the exterior and painted over, maintaining the container's aesthetic while providing effective insulation.

Insulation Panels: These panels offer excellent insulation relative to their thickness and are easy to install.

Blanket Insulation: Typically the most cost-effective option, blanket insulation comes in rolls and requires stud walls for installation, which can reduce floor space.

Eco-Friendly Options: If sustainability is a priority, consider eco-friendly insulation materials like wool or cotton, though they can be pricier.

Home design is also crucial. In rainy areas, incorporating a shed roof over the container can help manage water runoff and provide additional insulation. This type of roof can also serve as an ideal location for solar panels and rainwater collection systems, enhancing the home's sustainability.

Recognizing Signs of Potential Corrosion

Regular inspections are essential for a container home, as they are for any home.

The most vulnerable areas for rust and corrosion are where the container has been dented or damaged. After storms, check the roof and walls for any impacts; branches and acorns can create dings that compromise the paint or oxidation layer. Promptly repair any dents you discover.

Additionally, be vigilant about standing water on the roof, as it poses a significant risk to the container’s integrity.

Document any cosmetic rust spots you find; while they may seem harmless initially, they can grow and affect the home's stability over time.

Container homes are designed to withstand severe weather, including hurricanes and earthquakes. However, it’s crucial to inspect your container after any major weather events, as flying debris can cause damage that may lead to corrosion.

Treatment

Treatment should start as soon as the containers arrive on-site. It’s advisable to sandblast any rust to expose the bare metal. Once the surface is clear, you can proceed with priming, sealing, and painting.

If rust develops over time, use a wire brush and sandpaper to remove it effectively. After cleaning the area, apply vinegar and allow it to dry. Finally, paint the treated surface with an appropriate coating, such as ceramic paint or direct-to-metal paint, to protect the container from further corrosion.