One of the most frequently asked questions we receive is, “Should I remove the original container floor?” When converting containers into a home or office, one of the easiest ways to save money is by keeping the original container floor. However, the main concern with using the existing floor is safety.
Typically, container floors are made of tropical hardwoods that have been treated with harsh pesticides. These aggressive chemicals are dangerous to humans, so using the existing plywood floor is not recommended.
Maritime Container Floors
To understand the container floor, consider the original purpose of containers. They were designed to withstand the rigors of long-distance ocean travel and to protect the goods inside during transportation.
In most cases, container floors are made of one-inch marine plywood, constructed from tropical hardwoods such as Keruing or Apitong. Unfortunately, these types of hardwoods attract pests of all kinds. To prevent damage to the goods from insects and other creatures, the wood floors are treated with pesticides.
While this process is understandable for shipping purposes, it is not safe when using containers for building a home or office. These strong pesticides are harmful to humans, especially children and the elderly, so they should be avoided in container homes.
The good news is that many extremely harmful pesticides, such as Aldrin and Dieldrin, are now banned or highly restricted. However, other pesticides are still used in almost all container floors.
According to the Container Owners Association, a large percentage of container floors are still made with tropical hardwood. So, while many container manufacturers are exploring alternative flooring options like bamboo and steel, it is likely that your container floor has been treated with pesticides.
Inspecting Your Container Floors
If you are fortunate enough to purchase new containers, you can make specific requests to the supplier. You can ask for plywood floors that are not treated with pesticides. Alternatively, you can request the use of an alternative type of flooring such as steel or bamboo.
However, realistically, most people buy used containers rather than new ones when building with containers.
What should you do when building with used containers?
When building with used containers and treated plywood floors, some detective work will be required to determine if the floors are safe to keep.
To confirm what chemicals have been used to treat your floor, locate the Consolidated Data Plate, also known as the Safe Convention Plate, on the front door of the container.
This plate will usually have a section called “Wood Component Treatment.”
This section has three parts:
Part 1: IM (immunity)
Part 2: Chemical treatment
Part 3: Treatment date
Once you have discovered the information about the chemicals used in your container, determine if it will be necessary to remove and replace the floors.
Refer to the World Health Organization’s pesticide classification to better understand the severity of the chemicals used. Keep in mind that the data plate will not tell you everything. For example, if the container floor was damaged at some point and replaced, the plate will not reflect this.
Additionally, the data plate will not inform you of what was shipped inside the container or if any aggressive chemicals were spilled inside the container during its life at sea. If you are seeking more information about container brands, this document may be helpful.
Should You Remove the Original Container Floor?
In general terms, most people completely remove the original plywood floor and replace it with a new floor as a precaution. Ultimately, though, the decision is up to you and your budget. Needless to say, the safest route is to remove the original container floor and install a new one.
This will give you peace of mind and confidence that you have chosen the best option for your family and friends. Let’s now look at how to remove the floor and then discuss how to treat the floor if you decide to keep the original container floor.
How to remove the original container floor
To remove the plywood, you first need to cut the floor bolts using a handsaw or reciprocating saw. The bolts are fixed along the cross members and are usually spaced every twelve inches. Once all the floor bolts have been cut, use a pry bar to force the floor panels up and out of the container.
This is a relatively straightforward task but can take a surprising amount of time! Once the plywood has been removed, you can install your new floor. Another benefit of removing the original container floor is that once the floor is removed, you can insulate beneath the container.
With the floor removed, you can easily access the cross members of the floor and can apply spray foam or insulation panels with ease. Without removing the floor, it can be difficult to insulate beneath the container. Typically, you have to use a crane and then use spray foam while the containers are lifted.
How to treat the original container floor
If you have decided to preserve and treat your original plywood floor, this section is for you. The main concern with maintaining the original plywood floor is the hazardous fumes emanating from the pesticides used to eliminate pests.
Although the chemical potency will dissipate after a few years, there is still a risk. The floors need to be treated to be safe. The most popular solution is to apply epoxy to the floor. This will act as a sealant, containing the vapors emanating from the pesticides.
When choosing your epoxy, ensure that it is solvent-free and, most importantly, recommended for use on wood. Before applying the epoxy, clean the plywood with isopropyl alcohol. As a safety measure when applying isopropyl alcohol and epoxy, ensure there is sufficient ventilation. These fumes can be very strong and toxic.
If you do not wish to use epoxy, an alternative is to use a non-breathable floor base. Larry from Sea Container Cabin converted his used containers years ago and decided to use a non-breathable subfloor. The bottom layer of the floor was placed directly over the original plywood container floors, and tiles were then laid on top of the subfloor.
Another option we have seen is concrete. Again, similar to the base layer discussed earlier, concrete is used to “seal” the plywood floor. Before placing the concrete, a polyethylene plastic is placed over the original plywood. The concrete is then poured over the plastic.
In summary
Most containers have plywood floors made of tropical hardwood. This hardwood is treated with potentially harmful pesticides before being placed in the containers. This makes containers perfect for transportation but means that containers are not ideal for living as the pesticides used to treat the wood floors can also be harmful to humans.
Deciding whether to remove the original container floor or not is a personal decision. It depends on the history of your container, your budget, and your personal preferences.
If you have further questions or comments about the original container floor, please let me know in the comments section below.
