Build a 20-Foot Double-Wide Shipping Container With a Weldless Kit
Follow along as Channing tests a new DIY-friendly Double-Wide Shipping Container Kit designed to connect two 20-foot shipping containers into one large open-span structure.
Unlike traditional double-wide container builds that require extensive welding and structural fabrication, this system uses bolt-on components to create a low-profile connection between the containers. The result is a wider interior that could be used for a shipping container home, office, workshop, or other modular building.
Starting With MODBOX Shipping Containers
This project uses two MODBOX containers designed specifically with future modifications in mind.
Instead of the typical 60 mm square tubing along the upper sidewall, MODBOX uses a larger 60 x 80 mm rectangular tube. Rectangular tubing is also used along the floor instead of a traditional C-channel.
These changes add strength to the container after the sidewall corrugations are removed and help make a full 20-foot open span possible.
The lower rectangular tube also sits approximately flush with the finished wood floor, reducing the tripping hazard that can occur when joining standard shipping containers.
Installing the Weldless Double-Wide Header Kit
The bolt-in Double-Wide Header Kit is installed before removing the container sidewalls.
Multiple header components fasten directly into the upper structural tubing, helping keep the roof straight and properly supported while the corrugated wall panels are removed.
A 3-inch gap is intentionally maintained between the two containers. This provides enough space for specially folded flashing profiles while allowing water to drain between the containers instead of entering the finished interior.
The prototype was also water tested before and after spray foam insulation and remained leak-free.
Alignment Cones and Bridge Fittings
Container Modification World Alignment Cones help establish the exact 3-inch spacing between the containers.
Bolt-Style Bridge Fittings can then be used to pull the containers tightly together during installation. These are especially useful for DIY builders because they can align the containers without requiring specialized equipment.
Fork Pocket Sleeves are also installed between the containers to connect the two floors and reduce differential movement between them.
Together, the sleeves, center floor channel, and alignment system help make the two individual containers behave more like one structure.
Strut Channel Framing System
Inside, the container is finished using Container Modification World's strut channel framing system.
A lower strut channel acts like a baseboard, while upper profiles establish the wall and ceiling framing. Laser-cut strut strapping helps position the vertical framing consistently and keeps each strut parallel.
This system also makes surface-mounted electrical easy to install and modify later, making it particularly useful for commercial and industrial shipping container builds.
Wall Flashing Kits and Door Flashing Kits are used around the original container doors to create clean transitions between the framing, insulation, and finished surfaces.
Spray Foam and PVC Interior Panels
The interior is insulated with two-pound closed-cell spray foam before being finished with white PVC wall panels.
The spray foam creates a continuous insulated envelope while helping stiffen the container structure. The bright PVC panels reflect natural light and create a clean finished appearance inside the double-wide space.
A Mini Split Mounting Kit with MSS Exterior Brackets supports the exterior condenser while rubber isolators help prevent vibration from transferring into the shipping container.
A New DIY Double-Wide Container System
The finished structure combines two containers into one open interior using the Double-Wide Header Kit, Alignment Cones, Fork Pocket Sleeves, Bridge Fittings, Wall Flashing Kits, Door Flashing Kits, strut framing system, Mini Split Mounting Kit, and MSS Exterior Brackets.
The goal is to make double-wide shipping container construction more accessible by replacing complicated custom fabrication with repeatable bolt-on components.
For anyone looking to build a wider shipping container home, office, or modular structure, this system offers a promising new approach to joining containers while keeping the installation as DIY-friendly as possible.