Conex Box in Denver: A Complete Guide for Colorado Buyers

What is a Conex Box?

The word conex (sometimes spelled CONEX) is short for "container express," a term coined by the United States military in the 1950s for a standardized steel shipping container used to move equipment and supplies during the Korean War. The original CONEX boxes were 8.5 feet by 6 feet by 6.8 feet, much smaller than today's intermodal units, but the principle was identical: a stackable, lockable, weatherproof steel box that could move by truck, rail, or ship without unpacking.

By the late 1960s the commercial shipping industry had standardized on 20-foot and 40-foot intermodal containers (the units you see on every cargo ship and rail line today). The military term stuck in everyday speech. In Colorado, contractors, ranchers, and homeowners still call any large steel storage box a conex, even when the unit is technically an ISO shipping container or a purpose-built storage container.

For practical buying purposes the three terms describe the same thing in Front Range (Denver, Aurora, Colorado Springs), Western Slope, and mountain towns from Summit to Garfield County: a corrugated steel container, 20 or 40 feet long, with cargo doors on one end, designed to keep wind and water out for decades.

Conex Box vs Shipping Container vs Storage Container

The vocabulary lines up like this:

• Conex box. Originally a military-spec container. In modern use, a colloquial name for any steel shipping container used for storage. Applied to 20-foot and 40-foot units in residential and contractor settings.
• Shipping container. The technical term for an ISO-standard intermodal container. These are the units that cross oceans on cargo ships. They are built to ISO 1496 specifications, which dictate dimensions, lifting points, and structural strength.
• Storage container. A general retail and rental term used by ground-storage companies. Often refers to the same intermodal unit, but the phrase also covers purpose-built ground-level containers that have never seen ocean service.

If you are shopping for storage, the difference rarely matters. The same physical unit can be sold as any of the three. What matters more is the size, the condition grade, and the delivery logistics.

Standard Conex Box Sizes

The three standard sizes are:

• 20-foot standard. Length 20 ft, width 8 ft, height 8 ft 6 in. Roughly 1,170 cubic feet of interior space: an interior floor about 19 ft 4 in by 7 ft 9 in with 7 ft 10 in of height. Fits many residential driveways.
• 40-foot standard. Length 40 ft, width 8 ft, height 8 ft 6 in. Roughly 2,350 cubic feet of interior space. Best for contractors, ranches, and businesses.
• 40-foot high cube. Length 40 ft, width 8 ft, height 9 ft 6 in. The extra foot of headroom adds about 350 cubic feet of usable space, which matters when you store racked goods or tall equipment.

Uses by Industry

Containers can serve construction along the Front Range, cannabis cultivation and processing, wildfire rebuild work in Boulder and Larimer counties, and oil and gas service yards in the DJ Basin.

Uses include:

• Construction jobsite tool and material storage along the I-25 corridor. Steel walls, lockable doors, and on-site placement make a conex a substitute for a built shed, a fenced compound, or a temporary office.
• Cannabis cultivation and processing storage that meets state compliance requirements. Long-cycle uses where the container becomes part of the operation, not a temporary fix.
• Wildfire rebuild storage on Boulder, Jefferson, and Larimer county properties. Project-driven needs where timing, access, and short-term affordability all matter.
• Mountain-property gear storage for ATVs, snowmobiles, and seasonal equipment. Permanent storage for the things a garage or barn cannot fit.

How to Choose the Right Conex Box

Three questions narrow the decision:

1. How much space do you need? Photograph what you intend to store. A 20-foot unit holds the contents of a household storage unit, the materials for one residential framing job, or about ten standard pallets. A 40-foot unit doubles that.
2. How clean does the interior need to be? If you are storing tools, equipment, or boxed goods, a used wind-and-water-tight unit is fine. If the unit will be converted to an office, a workshop, or a clean-room storage space, a one-trip unit saves the cost of repainting and floor refinishing later.
3. Will it move? If the container will sit on a single property for the whole life of its use, buying makes sense. For a project that ends in a few months, compare the cost of renting from a rental company with the cost of buying.

How Delivery Works in Colorado

Conex boxes are delivered on a tilt-bed (sometimes called a roll-off) truck. The driver tilts the bed up, and the container slides off onto your placement site. Deliveries follow this sequence:

1. Site assessment. When you book, we walk through the access route, the placement spot, and overhead clearance. A 20-foot delivery needs 110 feet of straight clearance and at least 15 feet of driving clearance, with 22 feet of clearance along the entire unloading path. A 40-foot delivery needs 130 feet of straight clearance.
2. Surface check. Concrete, asphalt, gravel, hard-packed dirt, and grass all work. Soft, waterlogged, or steeply sloped ground may need preparation. We can advise.
3. Final placement. The driver positions the truck, levels the container, and confirms placement before leaving. Repositioning later is possible but usually requires a second visit.

Permits and Local Rules

Permit rules depend on the municipality. Urban codes are stricter, and some HOAs prohibit container placement entirely. Before ordering, check with your local building or planning department, and verify HOA rules if applicable. Our guide to permits in Colorado walks through common scenarios. See: Container permits in Colorado.

What a Conex Box Costs in Colorado

Pricing is ZIP-specific because delivery distance from the nearest depot drives a meaningful portion of the total. Tell us your ZIP and what you need, and a Container One sales representative will send back a quote. The written quote lists the delivery and container charges.

Frequently Asked Questions About Conex Boxes