--- title: "cross member: Definition and Meaning | NPSA" description: "A cross member is a steel beam that runs across the width of a container floor. It joins the two bottom side rails and supports the floor." url: https://npsa.preview.multisites.ai/glossary/cross-member publisher: National Portable Storage Association (NPSA) phone: "(816) 960-6552" email: info@npsa.org --- Container parts # cross member A cross member is a steel beam that runs across the width of a container floor. It joins the two bottom side rails and supports the floor. Extra cross members sit between the rails to hold the floor covering. It is a key part of the base frame and floor. ## Why it matters Cross members are the floor ribs of a container. They carry the weight of cargo, pallets and forklift wheels. For a storage operator, they matter when customers load heavy items or drive a forklift into the box. Rust, bent members or weak welds under the floor can make the box unsafe for loading. A common mistake is to look only at the top of the plywood floor. Water and rot can hide the damage underneath. Check the underside of the box during inspection, especially near the doors, where wheel loads are highest. If a unit has been floor-treated or repaired, ask what was done to the members. [Read: Shipping container sizes and dimensions for rental fleets](https://npsa.preview.multisites.ai/guides/container-sizes-and-dimensions) Definition source: [containerhandbuch.de](https://www.containerhandbuch.de/chb_e/stra/stra_03_01_00.html) ## Related terms [### bottom side rail A bottom side rail is the long steel beam along the lower edge of each side of a container. It joins the corner castings and holds the cross members that support the floor. Each box has two. It is a main part of the base frame of the box.](https://npsa.preview.multisites.ai/glossary/bottom-side-rail)[### marine plywood floor A marine plywood floor is the wood floor in a shipping container, made of thick laminated plywood fixed to steel cross members. Sea Box describes a 1 1/8 inch thick marine plywood floor. It carries the cargo load, including forklift traffic.](https://npsa.preview.multisites.ai/glossary/marine-plywood-floor)[### floor treatment Floor treatment is the chemical or coating treatment applied to a container's plywood floor. Container floors are often treated with pesticides to protect the wood from insects during transport. Treatments differ by maker. Ask the seller what treatment a floor has and whether it was sealed or replaced.](https://npsa.preview.multisites.ai/glossary/floor-treatment)[### payload Payload is the weight of cargo a container can carry. It equals the maximum gross weight minus the container's own empty (tare) weight. Carrier specs list payload next to tare weight for each container size and type, so buyers can compare them side by side.](https://npsa.preview.multisites.ai/glossary/payload)[### container inspection A container inspection is a check of a container's outside, inside, doors, floor and roof for damage, leaks and wear. Buyers do it before purchase. Operators do it when units go out and come back. It can be a quick look or a formal review to a standard.](https://npsa.preview.multisites.ai/glossary/container-inspection)[### forklift pocket A forklift pocket is a slot in the bottom side rail of a container. Forklift tines slide into it to lift and move the box. Twenty foot containers often have them. Many 40 ft containers do not. Check the maker's limits before any lift.](https://npsa.preview.multisites.ai/glossary/forklift-pocket) [All 220 terms](https://npsa.preview.multisites.ai/glossary) For the industry ## Grow your portable storage business with NPSA Members get event rates, the Community Forum, the directory listing and leads from this website. [Join NPSA](https://npsa.preview.multisites.ai/join-us)[See member benefits](https://npsa.preview.multisites.ai/member-benefits) Need storage? ## Get quotes from NPSA member companies Tell us what you need and where. A member company that serves your area will contact you. [Request a quote](https://npsa.preview.multisites.ai/request-a-quote)[Which unit do I need?](https://npsa.preview.multisites.ai/find-storage)