Since shipping container homes are built with metal boxes, we might wonder if the home built from shipping containers will eventually rust.
We have all seen shipping containers that are dented and rusted. Let’s take a look at what metal is used when building shipping containers and how to protect it from rusting and corroding.
Cor-Ten, used in shipping containers, (short for Corrosion resistant and Tensile strength) was designed in the 1930’s as a special metal with a special protective coating triggered by being exposed to oxygen during cycles of wet and dry exposures. Even though it has an oxide file as a corrosive resistant coating, it will still rust. The rust can be removed, primed, and painted to add protection from rust and corrosion in the future.
Here is what can be done to prevent rust from ruining your new shipping container home.
Selecting the Correct Shipping Container
Selecting a shipping container that does not have any or much rust is the best first step at preventing rust from forming in your container home.
If you bought a new shipping container, then it should be free from any rust or damages. But, buying a new shipping container can be expensive and will not contribute to having the home as an eco-friendly dwelling built with recycled parts.
Most shipping container home builders will buy “one trip” containers for their building blocks of their new home. There are several advantages to buy a “one trip” container that include:
- “One Trip” shipping containers are less expensive than new shipping containers.
- They often do not have very much damaged parts and are still water tight.
- They are environmentally conscience as a recycled home building material.
- Older and more used shipping containers might be less expensive than “one trip” shipping containers, but they might have a lot more rust, corrosion, dents, and water-tight issues. It often costs more in the long run to repair older shipping containers than it would cost to buy a “one trip” shipping container.
Properly inspect the shipping containers for structural rust and corrosion areas before purchasing them.
Structural Rust should be avoided
A common place that is overlooked when inspecting shipping containers for rust is underneath them. If the shipping container was left on the ground and not on blocking that would allow the air to flow all around the bottom of the shipping container, then trapped moisture could rust and corrode the metal at the underside of the shipping container.
Dents and damages can cause rust and corrosion in the damaged surfaces.
Any shipping container that has rust on the structural members should be passed up as a candidate for your new home. Don’t start your shipping container home building journey by having to repair the basic structural frame of the shipping container. So, if the floor joists, headers, or columns have a lot of rust or corrosion, pass it up and pick a better shipping container for your home.
Rust on the common surfaces that are not structural damage is acceptable because it can be repaired.
Another place that is overlooked is at the top of the container. If there are common surface and non-structural dents on the top of the shipping container, then water can pond on top of the container. This water can also cause the shipping container to rust and corrode away from easy eye inspection.
Depending on where you are shopping for your shipping container, the climate can have an affect on the condition of the shipping container.
Many shipping containers are sold near the ocean ports. There, the salty sea air and high humidity can accelerate the rusting on dented areas of the shipping containers. Inside the shipping containers, you might find condensation and mold. So, again, inspect thoroughly before purchasing your shipping containers.
Removing the Rust
So, you picked out the shipping container(s) best for your new home. Chances are, they are slightly used and they might have a few areas of rust.
To remove the rust, follow these steps:
Get Protective Gear
You will need to get gloves to protect your hands from the chemicals and abrasives that will be used to remove the rust. I like to use the West Chester Protective Dear yellow Nylon Gloves from Home Depot. They are lightweight and comes in a 3-pack.
Here is the link to those gloves rom Home Depot https://www.homedepot.com/p/West-Chester-Protective-Gear-Touch-Screen-Hi-Vis-Yellow-PU-Palm-Coated-Nylon-Gloves-3-Pack-HVY37165-L3P/301059326
Goggles and a face mask will be needed. Especially if you are going to have rusty dust and chemicals spraying near you.
Pick clothes that will protect your skin from coming into contact with some of the chemicals that will be used.
Since I will have a business attire on during the work week, I will often slip on coveralls you see me wearing in the photo below. The coveralls can be a little hot, so you might choose to wear something else.
If you want to get coveralls from Home Depot, you can find them at: https://www.homedepot.com/p/Walls-OUTDOOR-GOODS-Tatum-Long-Sleeve-Non-Insulated-Work-Coverall-63070NA9-L-RG/311885008
Where shoes that will cover your toes.
Get the proper tools
Use a wire brush to scrape off the loose rust parts. This will require a lot of physical labor and time. So, be patient.
Home Depot has a lot of different shapes and sizes. Pick the one that fits your needs.
Here is their link to the wire brushes: https://www.homedepot.com/p/ANViL-Soft-Grip-Carbon-Wire-Brush-4-x-16-Rows-SB416-ANV/309996562
Get sandpaper to smooth the areas that the rust was scraped off. Silicon carbide sandpaper, usually known as “wet/dry” sandpaper works best with rust. Although you will not need anything more fine of a grit than 320, this type of sandpaper comes in grits ranging from 80 to 1,000.
If you have a lot of rusty areas to remove, you might consider sand blasting the shipping container.
This is best to be done by a 3rd party who has the equipment to do this type of work. Care needs to be taken when removing rust and paint from the shipping container as to not ingest any dangerous particles that is removed from the metal surfaces.
Some people have used a wheel brush bit that is attached to a drill to remove stubborn rust areas. There are several sizes and grades of these types of bit. A common on is a 4 inch crimped wire wheel brush bit.
Home Depot has these wire brush bit at: https://www.homedepot.com/p/Milwaukee-4-in-Crimped-Wire-Wheel-Brush-48-52-5070/100015130
Priming the Rusted Area for New Paint
Get a liquid paint converter. This is a water-based formula that converts rust to a hard and paint-able surface. Read the instructions for the proper application. It might require several coats and time to set between the applications of each coat.
A 32 oz. container will cover up to 150 sq. ft.
It can be applied with a disposable paint brush or a rag.
After the paint converter starts to set, it will turn the rusted area black.
Here are some recommended paint converter/primers to prepare a rusted area for paint:
- Home Depot sells a paint converter called Krud Kutter. Here is a link to this product: https://www.homedepot.com/s/krud%2520kutter%2520rust%2520removalrust%2520converter?NCNI-5
- TotalBoat Rust Primer Converter
- Rust-Oleum Stops Rust Spray Paint Corroseal Water-Based Rust Metal Primer
- FDC Rust Converter ULTRA Primer.
- Krylon Rust Protector Primers.
Painting the Rusted Areas
After the proper rust converter/primer is applied and properly set, put the finish coat of paint on the entire metal shipping container.
The more coats, the better.
There are different types of finish paint that can be used. They all have their pros and cons.
Acrylic latex paint as a top coat can be used.
But, oil-based paints are the most durable. However, oil-based paint can crack and chip. It also can fade over time. So, if you use oil-based paint as the top coat, then consider using a product with a built-in fade protection.
Some have used paint with 90% dry zinc powder. Zinc is used to galvanize metals that are to withstand the outdoor elements. If you choose to use a zinc based paint, use all precautions to protect yourself from any dangers it may have to people that apply the paint on the shipping container.
Some Other Preventive Measures to Protect Your Home from Rusting
Build a roof over the shipping container to shed off the rain and snow. If it slopes, then it will allow the moisture to run off the top and not cause rusting on the top or sides of the shipping container.
If you are going to reuse the shipping container’s doors, then lubricate the doors with quality grease after removing the rust from the hinges.
Proper insulation and good ventilation will prevent condensation. Therefore, it will prevent rust from forming.
Closed cell insulation can be used in a cold climate area. It will act as an insulation and as a water barrier.
In tropical climates, let the walls breath with passive ventilation to prevent moisture to be collected that would invite rust and mold to form.
And finally, place the shipping container on a proper foundation and away from the ground. This will keep the moisture from the ground from deteriorating the bottom of the shipping container.