How to Lift Modular Buildings: Equipment, Spreader Beams and 4 Point Lifting
Lifting modular buildings requires careful planning, the right crane, and lifting equipment designed for the size, weight, and lifting points of the module.
Unlike many compact loads, modular buildings are typically long and wide. They may also have four, six, eight, or more designated lifting points. Connecting these points directly to a crane hook can create unfavorable sling angles and unwanted forces on the structure.
This is why spreader beams and spreader systems are commonly used when lifting modular buildings, modular homes, prefabricated buildings, and construction modules.
In this guide, we explain how modular building lifting works, how to select a suitable spreader beam, and what needs to be considered when planning a 4 point or multi point lift.
What equipment is used to lift modular buildings?
The exact lifting equipment depends on the weight, dimensions, structure, and lifting points of the module.
A typical modular building lifting setup can include:
- Mobile crane or crane truck
- Spreader beam, X-spreader beam, or spreader frame
- Top slings
- Bottom slings
- Shackles, hooks and links to enable 6- or 8-point lift
- Approved lifting points on the module
The spreader system creates distance between the lifting slings and allows the rigging geometry to better match the lifting points on the building.
For rectangular modules with four lifting points, an X-spreader beam can provide four separate connection points from one central lifting system.
Why are spreader beams used for modular building lifting?
One of the biggest challenges when lifting a modular building is its size.
Imagine a wide building module with lifting points located near each corner. If all four slings are connected directly from those points to a single crane hook, the slings need to travel inward toward the center.
This creates sling angles.
As the angle of a sling increases away from vertical, the tension in the sling increases. The angled slings can also introduce horizontal forces into the load.
A correctly selected spreader beam or spreader system allows the lower lifting slings to be positioned closer to the lifting points.
This can help:
- Improve the lifting geometry
- Keep lower slings closer to vertical
- Reduce unwanted horizontal forces on the module
- Provide clearance between slings and the structure
- Distribute the lifting arrangement across multiple lifting points
For large modular buildings, this can be especially important because walls, roofs, windows, cladding, and structural elements may not be designed to withstand forces caused by incorrect rigging geometry.
4 point lifting for modular buildings
Many modular buildings are designed with four lifting points, often positioned near the corners of the structure.
This makes 4 point lifting a common configuration.
An X-spreader beam is one way to create a four point lifting arrangement. Four arms extend from a central connection point, creating four positions for the lower slings.
The spreader can then be adjusted so that these connection points correspond more closely with the lifting points on the module.
This is particularly useful when the same lifting company handles modules of different lengths and widths.
Instead of using a fixed lifting frame designed for one specific module size, an adjustable spreader beam can be configured for several different lifting dimensions.
How to choose a spreader beam for a modular building
Selecting a spreader beam should not be based only on the total weight of the module.
Several factors need to be considered.
1. Total module weight
Start with the total lifting weight, including anything that will be lifted together with the module.
The complete lifting system must have sufficient capacity for the intended configuration.
2. Module length and width
The dimensions determine how far apart the lifting points are and therefore how much reach is required from the spreader system.
For an adjustable X-spreader beam, both the minimum and maximum working dimensions need to be considered.
3. Lifting point positions
The lifting points determine where the lower slings need to connect to the module.
They should always be lifting points that have been designed and approved for the intended lift.
4. Center of gravity
A module's total weight does not necessarily divide equally between its lifting points.
For example, a 20 tonne module lifted from four points does not automatically mean that every lifting point carries exactly 5 tonnes.
If the center of gravity is offset, some lifting points and rigging components can experience greater forces than others.
5. Sling length and sling angle
The geometry above and below the spreader beam affects the forces throughout the lifting system.
Sling length should therefore be considered during the planning stage.
6. Available lifting height
Spreader systems and slings require vertical space between the crane hook and the load.
On sites where lifting height is limited, the complete rigging height needs to be considered before selecting the setup.
How sling angle affects modular building lifting
Sling angle is one of the most important factors in any multi point lifting arrangement.
When a sling is vertical, its force acts primarily in the vertical direction.
As the sling moves further away from vertical, the tension required to support the same vertical load increases.
This means a sling cannot be selected based simply on dividing the total load by the number of slings.
For example, in a 4 point lift, it would be incorrect to automatically assume that each sling only needs to support exactly 25 percent of the total load.
The actual forces depend on several factors, including:
- Sling angle
- Load distribution
- Center of gravity
- Rigging geometry
- Lifting point positions
These forces should be determined as part of the lift planning process.
Aluminium vs steel spreader beams for modular lifting
Both aluminium and steel spreader beams can be used for lifting large modules, depending on the required capacity and dimensions.
One major advantage of aluminium is weight.
A lighter spreader beam can be easier to transport, handle, and prepare on site. It also means less lifting equipment weight is suspended from the crane hook.
This can be particularly useful for crane trucks where equipment needs to travel with the vehicle from one job to another.
Steel becomes useful when significantly higher capacities or larger configurations are required.
At Aluexbeams, our spreader beam range includes both aluminium and steel systems for different lifting requirements.
Adjustable spreader beams for different module sizes
Modular construction does not always mean standardized lifting dimensions.
One module might be long and narrow, while the next could be considerably wider. Lifting point locations can also vary between manufacturers and projects.
This is where adjustable spreader beams become useful.
Aluex X-spreader beams have adjustable arms that allow the lifting dimensions to be changed according to the load.
This allows one spreader system to be used across a wider range of lifting applications instead of requiring a separate fixed spreader frame for every module dimension.
For lifting companies handling modular buildings regularly, this can also reduce the amount of lifting equipment that needs to be transported between jobs.
Lifting modules with more than four lifting points
Not every modular building can be lifted from four points.
Large or structurally sensitive modules may use six, eight, or more lifting points.
Additional lifting points can be required because of:
- Module length
- Structural design
- Weight distribution
- Maximum permitted load at individual lifting points
- Requirements specified by the module manufacturer
In these situations, the spreader system needs to distribute the load across the required number of lifting points.
For example, an Aluex 50 can be combined with Aluex Link components to create an six or eight point lifting arrangement.
We have used this type of configuration for lifting the module in the image below:
The important principle is that the lifting system should be configured around the requirements of the load, rather than forcing every load into the same four point lifting arrangement.
How to protect a modular building during lifting
A modular building is not simply a heavy object.
Windows, walls, roof structures, cladding, insulation, and other components can be vulnerable to contact or horizontal forces during lifting.
The rigging should therefore provide sufficient clearance between the lifting slings and the building.
Using a spreader system can position the upper connection of the lower slings closer to the module's lifting points. This can reduce the need for the slings to travel sharply inward toward the crane hook.
However, the spreader beam itself does not determine whether a lift is safe.
The complete lifting arrangement must follow the module manufacturer's lifting instructions, the lifting equipment manufacturer's instructions, and the approved lift plan.
Transporting modular building lifting equipment
Transportation is another factor that is sometimes overlooked when choosing modular building lifting equipment.
Large fixed spreader frames can occupy considerable space on a truck.
If a crane operator performs several different types of lifts, carrying a large dedicated lifting frame may not always be practical.
Foldable, adjustable, or detachable spreader systems can make transportation easier.
Several Aluex X-spreader beams are designed so that their transport dimensions can be reduced when they are not being used.
The goal is simple: carry the lifting equipment with the crane truck and configure it when it is needed.
Modular building lifting checklist
Before lifting a modular building, the lifting team should have the information required to verify the complete lifting arrangement.
At minimum, consider:
- Total lifting weight
- Module length and width
- Center of gravity
- Number of lifting points
- Position of each lifting point
- Capacity of each lifting point
- Required spreader dimensions
- Spreader beam capacity
- Sling capacity
- Sling length
- Sling angles
- Shackles and connection hardware
- Crane capacity at the required radius
- Available lifting height
- Clearance between rigging and the module
- Manufacturer's lifting instructions
- Site specific lift plan
We have developed a lifting planner to calculate this more accurately:
Aluex Lifting Planner: (it's free to use)
https://aluexbeams.com/pages/lifting-planner
Choosing modular building lifting equipment
There is no single spreader beam configuration that works for every modular building.
A small modular home and a 25 tonne construction module can require completely different lifting arrangements.
The starting point should always be the load itself.
Determine the weight, dimensions, center of gravity, lifting point positions, and lifting requirements first. From there, the appropriate crane, spreader system, slings, and connection equipment can be selected.
At Aluexbeams, we manufacture adjustable aluminium and steel spreader beams in Finland for lifting applications from 2 to 50 tonnes.
Our X-spreader beams are designed for applications where multiple lifting points, adjustable dimensions, low equipment weight, and efficient transportation are important.
If you need help finding a spreader beam for lifting a modular building, send us the weight, length, width, and lifting point positions of the module. We can help identify an Aluex configuration for the application.