Have you ever wondered what's required to remove the entire side of a shipping container?
In this video we're going to show you a couple different methods on how to structurally reinforce the container to allow you to remove an entire side. This is something a lot of people would be interested in doing if they plan on joining two containers together.
In this video we have a 20-foot shipping container that we're modifying (it's actually a hazardous material storage unit). The customer is going to be leaving the side wide open (kind of like a horse shelter) and because of that we are putting containment pans inside.
How to Structurally Reinforce a Shipping Container After Removing an Entire Side
Removing an entire side panel from a shipping container is one of the most aggressive modifications you can make. Whether you're joining two containers together, building a double-wide, or creating an open-sided hazardous material shelter, structural reinforcement is critical.
In this breakdown, Channing McCorriston, The Container Guy, explains practical methods to maintain container integrity after cutting out a full side wall.
Why Side Removal Requires Reinforcement
Shipping containers are designed as structural boxes. The corrugated side walls play a major role in:
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Load distribution
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Preventing floor sag
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Supporting roof loads
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Maintaining overall rigidity
Once an entire side is removed, the container loses a significant portion of its structural strength. Without proper reinforcement, the floor can sag and the roof can bow.
Floor Reinforcement Strategies
When corrugations are removed down to floor level, the bottom rail and floor system weaken.
Maximum Unsupported Span
Roughly 10 feet of unsupported span is the limit before reinforcement becomes necessary.
Reinforcement Options
Several methods can restore floor strength:
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Welding a ¾-inch thick flat bar (around 5 inches wide) along the bottom channel
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Folding a steel section into a box profile for added rigidity
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Installing heavy flat bars inside the bottom rail to prevent sag
Keeping the bottom channel intact wherever possible greatly improves structural performance.
Containers should also sit on properly leveled foundations. On concrete pads, holes may be chiseled to seat corner castings evenly and prevent twisting.
Wall and Roof Reinforcement
With the side wall removed, vertical and roof loads must be redirected.
J-Channel Structural Support
A laser-cut, folded 1/8-inch (11-gauge) mild steel J-channel can be installed inside the container to replace the structural function of the removed wall.
This J-channel:
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Provides strength across the span
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Can double as a rain drip
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Helps prevent water ingress
Header Installation
Headers support the roof once the side wall is gone.
Important considerations:
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Headers often include a slight pre-camber (an upward curve)
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This prevents sagging under snow load
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Bracing must be even and controlled
Improper tensioning during installation can cause uneven settling, especially when joining two containers together.
Special Considerations by Container Size
20-Foot Containers
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Standard structural design
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Side removal manageable with flat bars and HSS tubing
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10-foot unsupported spans before reinforcement
40-Foot Containers
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Similar structural logic to 20-foot units
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Headers can be positioned above the top tubing for full-height interior clearance
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Reinforcement techniques scale accordingly
53-Foot Containers
53-foot containers are structurally different.
Key differences include:
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Structural posts at the 40-foot mark
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A 12-inch-tall bottom channel
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Approximately 5.5-inch floor depth
Cutting the bottom channel on a 53-foot container can cause irreparable sagging.
Full side removal is not recommended. Instead:
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Remove partial corrugations
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Install vertical support posts from floor to ceiling
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Use shorter header spans (around 18 feet) instead of attempting a full 38-foot opening
Reinforcement often requires flat bars and 2x5 HSS rectangular tubing, making it significantly more expensive and labor-intensive.
Recommended Modification Workflow
A safe workflow for side removal includes:
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Cut a small center section first
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Install a temporary floor-to-ceiling support post
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Remove corrugations progressively
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Use forklift assistance to stabilize panels
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Tack weld structural reinforcements externally
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Complete final welds indoors for better quality control
Temporary bracing with jacks or teleposts must maintain even pressure to prevent distortion.
Headroom Tradeoffs
Installing headers inside the container reduces interior headroom by approximately 10 inches.
While this is a cost-effective alternative to expensive double-wide header kits, it must be factored into final design plans.
Water Management Considerations
Structural reinforcement can also serve dual purposes:
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J-channels can act as rain drips
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Ridge caps and flashing can prevent water ingress
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Maintaining corrugation profiles where possible improves weather resistance
Water control should always be integrated into structural modifications.
Key Takeaways
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Removing a full container side eliminates critical structural components
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Floor sag becomes a risk beyond 10 feet of unsupported span
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Flat bars, box sections, HSS tubing, and J-channels restore strength
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53-foot containers require special caution
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Temporary bracing and careful welding are essential
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Keeping the bottom channel intact wherever possible is critical
Final Thoughts
Side removal is not just a cutting job — it is a structural engineering task.
Understanding how loads transfer through the floor, walls, and roof ensures that modified containers remain safe, level, and durable.
With proper reinforcement techniques, it is possible to safely create large open spans for double-wide builds, shelters, and industrial applications — but only when the structural system is carefully rebuilt.