Steel Modules vs. Wood Modules: Choosing Materials in Construction Transportation Logistics

Wood Modules vs. Steel Modules

When it comes to prefabricated modular construction, the debate on using wood modules vs. steel modules usually goes like this: Steel offers the most durability, but wood modules are popular for their energy efficiency, affordability, and ease of upkeep. These are important considerations, of course. But, in our firsthand experience with construction logistics, there’s more to the discussion. Whether wood or steel, you have to figure out how to get your modular homes or buildings from the factory to the build site, and both come with their own set of problems and parameters.

Here, the Stream Logistics team weighs in on what you need to know about transporting wood modules vs. steel modules in offsite construction logistics. 

The Basics

Before we take a closer look at the different ways of transporting wood modules vs. steel modules, you have to understand the main differences between the two. We won’t get into all the pros and cons of each — instead, focusing on how their innate properties affect how you need to transport them.

Wood Modules

• Bigger
• Heavier
• More fragile
  

Wood modules are moderately strong and are typically used for large-scale, low-rise projects. Because of this, wood modules are often already outfitted with everything inside, from drywall to FF&E. So while wood is technically lighter than steel, wood modules tend to be heavier because they’re bigger, require more material to make, and are usually fully outfitted inside.

Additionally, because wood modules have torque and twist more easily, transporting them can get tricky. Due to the nature of the wooden structure, there’s always an increased risk of some sort of damage to the finishing inside (like cracked tiles or damaged drywall). The right transport partner will help you figure out how to minimize that. 

Steel Modules

• Smaller
• Lighter
• More rigid
  

On the other hand, steel modules are typically smaller and, to the surprise of some, lighter. Because these mods tend to be smaller — in width, length and even height — steel modules weigh less than wood modules, simply because there is less material. 

By nature, steel modules are more rigid than wood modules, meaning they’re less fragile to transport. Plus, their smaller boxy shape allows them to be transported in a totally different way than wood modules, which we’ll explain. 

Did you know? ​​Wood modules can weigh up to 65,000 pounds, whereas steel modules tend to weigh under 50,000 pounds.

Transporting Wood Modules vs. Steel Modules

With different shapes, weight and degrees of sturdiness, wood and steel building modules have to be handled differently. From the way you load these building components onto trailers to the kinds of trucks you need to transport them.

How do you get wood modules vs. steel modules onto the truck?

The way you get wood modules vs. steel modules onto the truck is very different. Because steel modules are so rigid, boxy and strong, you can use corner castings as hook points for the module and lift it up via a crane to place it on the trailer. When transporting a wood module, however, the module needs to be more supported and lifted in the air as infrequently as possible. 

Do wood and steel modules need different transportation?

The simple answer is yes. Because steel modules can be lifted up from the top, it doesn’t matter what kind of trailer you put it on. You will always have access to the top. Common trailers for steel modules include standard flatbeds, stepdecks, lowboys, and RGNs. The flexibility of trailer type usually makes it easier and cheaper to source trucks for steel modules.

On the other hand, it is best to avoid lifting wood modules via crane. Because of this, most factories prefer to use self-loading and unloading trailers (aka floats), which have the ability to move the carrier up and down. 

It’s important to note that even if you could crane the wood module onto a trailer, the risk for damage and the size of larger modules increases risk of damage. The twisting and torquing that can occur in the air when lifting a wood module can be detrimental. So, hydraulics are the safest bet. But, these trucks are harder to source, and you need an expert driver behind the wheel. 

How do staging yards play into transporting wood modules vs. steel modules?

Many times you’ll work with a staging yard because the manufacturer needs to get the modules out or the build site isn’t ready yet. When you send wood modules to a staging yard, they’ll be taken on and off the hydraulic truck chassis with the help of cribbing. These are basically jacks that hold them up so that when the trailer comes back, it can slide underneath the module, lift it up, the cribbing can be removed, and the module can go on its way. 

On the other hand, moving steel modules is trickier. While they can be lifted easily from the top, you need to bring in cranes and crane operators on site to move them, as well as other crews to guide the modules and keep everything moving. Typically, this is still an affordable option, but the cost of crane equipment and labor does reduce cost savings you get from being able to use just about any truck. 

What are the pros and cons of using wood modules vs. steel modules?

Wood Modules

• Easy to load in the staging yard with the right equipment

• Can only be loaded with specialized hydraulic trucks
• Hydraulic trucks are more expensive and can be harder to source

Steel Modules

• Can be lifted onto just about any truck
• Many more truck options that are cheaper and easier to source
• Crane operators and the crew at staging yard do add on to the price

What other transportation logistics do I need to keep in mind?

Whether you’re moving wood or steel modules, you’re going to need an expert to help you figure out everything from local and federal laws for transportation to permits and escort cars for these oversized loads. A trusted logistics team is also going to help you source the right kind of equipment, whether it’s cranes for offloading steel modules or top-of-the-line hydraulic trucks to move your wood modules. 

Pro-tip

When it comes down to it, it’s all about asking the right questions — like if they have worked with your kind of modules before and if they know what’s needed to move them. 

We’re happy to answer anything you need to know about moving different kinds of prefabricated modular buildings. It’s what we do! 

Stream Modular is a transportation logistics company specializing exclusively in modular construction. We help modular manufacturers and builders transport mods, pods and panels so they arrive on time and safely to the build site.

Read more: 

• Bringing It Home: The Transportation and Assembly of Modular Buildings is a Science and an Art
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