What Is a Conex Box?
A conex box is a portable steel container manufactured to International Organization for Standardization (ISO) specifications so it can stack and interlock on ships, rail cars, and chassis worldwide. The term “conex” is short for “container express,” a designation that dates back to standardized military and freight shipping systems.
Every conex box shares a few defining traits: a Corten (weathering) steel shell, a rigid corner-casting frame for stacking, cargo doors on at least one end, and a marine-grade plywood floor. Because these units are built to a global standard, a 20-foot conex box in Houston has the same core dimensions as one in any other U.S. port city.
Why Houston Businesses Choose Conex Boxes
Houston’s economy makes it one of the most active conex box markets in the country. As home to the Port of Houston — one of the busiest ports in the United States by tonnage — the region has deep, established supply chains for ISO steel containers.
Several local industries drive steady demand:
- Energy and oil & gas: secure on-site storage for tools, parts, and equipment across the Energy Corridor and surrounding facilities.
- Construction: lockable job-site storage and mobile offices that move as projects progress.
- Retail and events: modified containers used as pop-up shops, concession stands, and ticket booths.
- Agriculture and ranching: durable equipment and supply storage across the greater Houston area.
- Logistics and warehousing: overflow inventory storage that supplements fixed warehouse space.
Conex Box Sizes Available in Houston
The three standard sizes cover the vast majority of Houston use cases. The table below summarizes the key specifications buyers reference most.
| Size | Exterior Dimensions (L×W×H) | Approx. Floor Area | Common Houston Use |
| 10 ft | 10′ × 8′ × 8.5′ | ~80 sq ft | Compact storage, guard shacks, tight lots |
| 20 ft | 20′ × 8′ × 8.5′ | ~160 sq ft | Most popular: contractors, retail, general storage |
| 40 ft | 40′ × 8′ × 8.5′ | ~320 sq ft | Large inventory, equipment, office conversions |
| 40 ft High Cube | 40′ × 8′ × 9.5′ | ~320 sq ft | Extra vertical clearance for tall items or builds |
The 20-foot conex container is the single most common size purchased, offering a balance of capacity and footprint. The 40-foot-high cube adds a full foot of interior height (9.5 ft exterior) for applications that need vertical space, such as retail conversions or racked storage.
Types of Conex Boxes for Houston Buyers
Beyond size, conex boxes are configured for specific jobs. Houston buyers typically choose from the following categories.
| Container Type | Best For |
| Standard cargo door | General-purpose storage with full-width end doors |
| Roll-up door | Frequent access, warehouse-style loading |
| Walk-in door | Personnel access alongside cargo openings |
| Office containers | On-site workspaces with insulation, electrical, and A/C packages |
| Refrigerated (reefer) | Temperature-controlled storage for perishables |
| Insulated | Interior climate stability for sensitive goods |
| Open-side / full-side open | Easy loading and unloading of wide or bulky cargo |
| Custom-modified | Concession stands, guard shacks, break rooms, security offices |
New vs. Used Conex Boxes: Which Should Houston Buyers Choose?
Both new and used conex boxes are widely available in the Houston market, and the right choice depends on budget and intended use.
- New (one-trip) conex boxes have made a single voyage from the manufacturer, so they show minimal wear and a cleaner exterior. They suit buyers who want the longest service life or plan visible-use conversions like offices and retail spaces.
- Used conex boxes are more budget-friendly and remain structurally sound for storage and industrial applications. They may show cosmetic surface marks but retain the strength that makes steel containers reliable for long-term use. For straightforward storage on a Houston job site or yard, a used unit often delivers the best value.
What Affects Conex Box Pricing in Houston?
Conex box prices are not fixed — they move with several factors buyers should weigh before requesting a quote:
- Size: 10ft, 20ft, and 40ft units are priced in ascending order by material and capacity.
- Condition: new/one-trip units carry a premium over used containers.
- Configuration: roll-up doors, windows, insulation, office build-outs, and refrigeration add cost.
- Market supply: availability of specific sizes and grades at a given time.
Because these variables combine differently for every order, the most accurate way to price a conex box in Houston is a direct quote. Aztec Container provides up-front, transparent pricing with no hidden fees.
How to Choose the Right Conex Box in Houston
Use this quick framework to narrow your options before buying:
- Define the primary job:Â storage, office, retail, refrigeration, or a custom build.
- Measure your space:Â confirm the lot or yard can accommodate a 10ft, 20ft, or 40ft footprint.
- Set access needs:Â decide between standard cargo doors, roll-up doors, or a walk-in door.
- Choose condition:Â balance budget against appearance and intended service life.
- Add modifications early:Â specifying windows, doors, or electrical up front is more efficient than retrofitting later.
About Aztec Container
Aztec Container is a leader in the sales of steel ISO shipping containers, storage containers, custom office containers, & conex box sea containers. Our company has built durable containers since 1969 and serves customers nationwide, including Houston and the greater Texas market. Aztec Container is a member of the National Portable Storage Association (NPSA) and has served clients ranging from municipalities to federal agencies.
Call 1-800-399-2126 for a quick quote.
Frequently Asked Questions
What exactly is a conex box, and is it the same as a shipping container?
Yes — “conex box” is another name for a steel ISO shipping container. The term comes from “container express.” In Houston, people use “conex box,” “shipping container,” and “steel storage container” interchangeably to describe the same standardized steel units.
What sizes of conex boxes can I buy in Houston?
The three standard sizes are 10-foot, 20-foot, and 40-foot, plus a 40-foot high cube that adds a foot of interior height. The 20-foot box is the most popular choice for general storage and contractor use.
How much does a conex box cost in Houston?
There’s no single price — cost depends on size, whether it’s new or used, and any modifications like roll-up doors or insulation. The fastest way to get an accurate figure is to request a quote at 1-800-399-2126.
Should I buy a new or a used conex box?
It depends on your goal. New (one-trip) boxes look cleaner and suit office or retail conversions. Used boxes cost less and are structurally solid for storage and industrial jobs. Many Houston buyers pick used units for straightforward storage to save money.
What are conex boxes made of?
They’re built from Corten (weathering) steel with a rigid corner-casting frame and a marine-grade plywood floor. This construction is what gives conex boxes their strength and long service life.
What do Houston businesses typically use conex boxes for?
Common uses include job-site storage for construction, secure equipment storage in energy and oil & gas, mobile offices, retail pop-ups, concession stands, and agricultural supply storage across the greater Houston area.
Can a conex box be customized?
Absolutely. Conex boxes can be modified with roll-up doors, walk-in doors, windows, insulation, electrical packages, and full office build-outs. Aztec Container offers custom units in 10ft, 20ft, 40ft, and 45ft sizes.
What’s the difference between a standard 40ft box and a 40ft high cube?
Both are 40 feet long and 8 feet wide, but the high cube is 9.5 feet tall on the exterior versus 8.5 feet for a standard unit. That extra foot of height helps with tall items, racking, or interior build-outs.
Are conex boxes secure for storing valuable equipment?
Yes. Their steel construction and lockable cargo doors make them a common choice for securing tools, equipment, and inventory. Lockbox add-ons can provide an extra layer of security for higher-value contents.
Why buy a conex box from Aztec Container?
Aztec Container has supplied steel ISO containers since 1969, offers nationwide sales including Houston, and maintains transparent pricing with no hidden fees. As an NPSA member with a long track record, it’s an established source for both standard and custom conex boxes.