What to Inspect Before Buying a Used Unit?

AI Summary

• Inspecting a used shipping container correctly ensures you get a durable, weather-tight, and structurally sound unit.

• Key inspection areas include exterior integrity, doors and seals, flooring, roof condition, rust levels, and frame alignment.

• A thorough check prevents problems like leaks, corrosion, and warped doors that affect usability and lifespan.

• Mann’s Cans offers reliable used containers and guidance to help buyers choose units that meet storage or custom build-out needs.

Buying a used shipping container is an excellent way to gain secure, long-lasting storage or begin a custom build-out project at an affordable cost. Used units can perform exceptionally well for decades, but only if they are inspected properly before purchase. Not all containers age the same way. Factors like ocean exposure, handling, and time in service affect their condition, which is why knowing what to look for is essential.

This guide walks you through the most important things to inspect before purchasing a used shipping container so you can invest confidently and avoid future repairs or structural issues.

The Problem: Used Containers Vary Greatly in Condition

Although shipping containers are built to be durable, years of use can cause:

• Corrosion or deep rust spots

• Dents that compromise structural integrity

• Roof damage leading to leaks

• Stiff or misaligned doors

• Damaged flooring from heavy loads

• Worn weather seals that no longer keep moisture out

  
  

Many issues are easy to miss unless you know what to check. Failing to inspect a unit properly can lead to unexpected maintenance costs, moisture damage inside the container, or difficulty using the doors.

The Solution: A Detailed, Step-by-Step Container Inspection

Step 1: Examine the Exterior Walls

Walk around the entire container and look for:

• Large dents or creases that affect the structure

• Areas with deep rust or corrosion

• Bowing or bulging panels

• Previous repairs or patches

  
  

Surface rust is normal on used units, but deep flaking or pitting indicates weakened metal. Structural dents near corners or edges may reduce durability, especially if you plan to stack units or convert the container into a custom structure.

Step 2: Inspect the Corner Castings and Frame

Corner castings are critical since they carry most of the container’s structural load.

Check for:

• Cracks or deformation

• Excessive rust

• Weld damage or repairs

  
  

Also, inspect the bottom and top frame rails to make sure the container is square and not leaning or twisted. A warped frame can make the doors nearly impossible to operate smoothly.

Step 3: Check the Roof for Damage or Water Concerns

Climb up only if it is safe, or view from a higher vantage point.

Inspect for:

• Standing water that indicates sagging

• Soft spots in the steel

• Rust holes or thinning metal

• Previously patched areas

  
  

Roofs endure the harshest weather exposure, so this is one of the most important inspection points. Even small dents can trap water and lead to leaks over time.

Step 4: Test the Doors and Locks

Doors should open fully and seal tightly.

Evaluate:

• Door alignment

• Ease of opening and closing

• Rust around hinges and locking bars

• Functioning gaskets and rubber seals

  
  

Stiff or misaligned doors often indicate frame warping. Worn seals can allow moisture and pests inside, causing damage to your stored items.

Step 5: Inspect the Floor for Structural Integrity

Most container floors are made of marine-grade plywood supported by steel crossmembers.

Check the interior for:

• Soft spots or rot

• Deep gouges or cracks

• Oil or chemical stains

• Loose boards

  
  

Flooring issues may affect load capacity and interior usability, especially if you plan to convert the container into a workspace or insulated unit.

Step 6: Look Inside for Light Leaks

Light leaks are an easy way to identify hidden holes.

To check:

• Close both doors

• Look for sunlight entering through pinholes or gaps

  
  

Any visible light means the walls or roof have openings that could allow moisture, insects, or drafts inside.

Step 7: Smell for Odors or Contaminants

Previous container use matters. Some units hauled food, textiles, or household goods, while others held industrial materials.

Inspect for:

• Strong chemical smells

• Mold or mildew

• Residue from previous cargo

  
  

If the container has a persistent odor, it may require deep cleaning or may not be suitable for certain uses.

Step 8: Review the Container’s Grading or Condition Rating

Used containers are often categorized as:

• Cargo-worthy (CW)

• Wind and Watertight (WWT)

• As-is

  
  

CW units meet shipping standards, WWT units are suitable for storage, and as-is units may need repairs. Know which category you’re purchasing.

Step 9: Confirm Measurements and Structural Needs for Your Project

Before finalizing your purchase, consider how you plan to use the container.

Ask yourself:

• Is the size (20 ft or 40 ft) sufficient for storage or build-out plans?

• Do I need extra height (high-cube units)?

• Will I modify the walls or add utilities?

• Do I need a unit with excellent door function for daily access?

  
  

Planning ahead prevents choosing a unit that doesn’t align with long-term goals.

People Also Ask

Are the used containers still secure?

Yes. Even used units offer strong steel construction. Just ensure the locks, doors, and frame are in good condition.

What level of rust is acceptable?

Surface rust is normal. Deep rust, holes, or flaking metal can compromise structural integrity.

Do used containers leak?

Not if you choose a wind and watertight unit. Always inspect the roof and corners thoroughly.

FAQ Section

Q: How long does a used container typically last?

A: With proper care, many used containers last 15 to 25 additional years on land.

Q: Can used containers be customized?

A: Absolutely. Used units are great starting points for offices, workshops, storage, and specialty build-outs.

Q: Do used containers require maintenance?

A: Minimal maintenance is needed. Inspect seals, repaint exposed metal, and ensure proper drainage around the site.

Q: Should I buy a used or new container?

A: Used containers are more affordable and suitable for most storage or build-out needs. New one-trip units offer the cleanest condition and longest lifespan.

Find a Reliable Used Unit You Can Trust

A thorough inspection is the key to choosing a used container that performs well for years. By checking structure, doors, flooring, seals, and overall condition, you ensure you’re investing in a secure, weather-tight, dependable unit. Whether you need storage or plan to build something unique, selecting a quality used container makes all the difference.

Mann’s Cans offers dependable used units and expert guidance so you can choose confidently and avoid common issues.

Call 724-790-5040 or fill out the online form to explore available used containers and get help selecting the right one for your property.