Shipping container flooring has seen various changes over the years, and the type of flooring can depend on the type of container or the company that originally had the container built. If you’re plans are to purchase a container for intermodal shipping or to use as a mobile storage unit, you may not need to be overly concerned with the flooring material and structure. If you plan to modify a container into a modular housing unit or some other type of residence, you may want to consider the structure of the container and flooring material.
|The structure of the floor is typically made of steel joists or cross members that are six inches deep (150mm), and placed 20 inches apart (508 mm). These cross members run across the container and are welded to each of the beams on either side of the container. This design allows for the weight to be carried corner posts and the floor. If you make any modifications to the cross members it can weaken and compromise the structural integrity of the container. Without any modification, containers can carry as much as 30 tons; enough to support the weight of a forklift packing the container with cargo.
The container flooring itself can be made from several different materials. Historically, it has been constructed from 25-30mm thick marine plywood, consisting of the hardwoods Apitong or Keruing. Wood is ideal because of its strength, ability to withstand abuse and resist denting, and its natural friction. And while these two woods are strong and pest resistant, the available supply has decreased in availability of over the years.
A recent trend has been to use bamboo flooring in shipping containers. Bamboo grows quickly and can be cut in similar sizes to plywood. Another alternative to the traditional Apitong or Keruing is steel flooring. The steel flooring typically plates designed with a non-stick pattern or painted.
Refrigerated shipping containers typically have aluminium flooring. The aluminium flooring is designed to have "T" section planks running the length of the container. The planks are raised slightly to allow for cold air flow and circulation. In some cases, refrigerated containers used for domestic transport have flat aluminium checked plate flooring.
Modifying or replacing the flooring is relatively easy, by design. It’s normal for the floor to have some natural "wear and tear". Expect some cracks, holes, or missing layers in the shipping container floor. Considering the history of the flooring is typically unknown, and it’s safe to assume that it’s been treated with various chemicals to prevent insects or rodents from destroying it. It’s often suggested that the flooring be replaced rather than covered over. If you’re not able to replace the flooring then it’s a good idea to seal the floor with polyurethane or apply a coat of epoxy paint. Most importantly, be very careful if you sand the floor. Sanding can release trapped fumigants and the exposure could be dangerous. After a couple of years the fumigants and chemicals will naturally dissipate, but it’s always good to take extra precautions.