5 Observations about Prefabrication

Why is Australia so far behind other nations 
when it comes to prefab or offsite site modular?

That's the question someone posted at Australian Construction Innovation, a LinkedIn group. Curiously, I hear the same question about prefabricated construction in the United States. So the question is one of perspective.

My sense is that prefabrication is at exactly the right level. Here are five reasons:

1. Prefabrication is very common.

Consider: Prefabricated trusses, metal buildings, precast concrete structures, HUD Code (mobile) housing, prefabricated classrooms, panelized wall systems, and more. Cutting and bending concrete reinforcing used to be done on site; now its prefabricated. I can cite many similar examples.

2. Large Scale Integration are Vulnerable to Economic Cycles. 
I was a consultant to a firm that built a highly automated factory to prefab panels for complete building structures. The high-performance, semi-finished panels assembled quickly in the field to enclose entire buildings in a single day. Then the Great Recession of 2008 hit. While it hurt all of us, capital intensive companies were hit harder. When work fell away the firm had to idle the factory and then went bankrupt due to financing costs.

3.  Site Work Can't be Prefabricated.
Next time you hear about how quickly the Chinese can erect a prefabricated building, note that the days until completion does not include the time it takes to run utilities to the site, place foundations, and attend to other sitework. When projects are built on site, above ground construction overlaps the sitework.

4.  Prefabrication Imposes Design Restraints.
While fabrication automation continues to improve, no prefabricated whole-building system can provide as much design flexibility as a project assembled from open sourced components. Designers and developers like flexibility. They also require it to deal with unique site conditions.

5. Site Assembly Is Amazingly Efficient.
This is my favorite explanation. Today's construction systems can be really efficient. Consider what the screw gun and pneumatic fasteners mean to the time required for framing. Concrete masonry units may take more time to set than precast, but they are in inventory and can can be installed in the time it takes to engineer, get approvals, fabricate and ship prefab components.

Looking ahead, the whole discussion about prefab will change when we start using onsite systems to print structures, assemble them with robots, or using other emerging technologies.

prefabAUS, an Aussie trade association that promotes prefabrication says, on its website, "Prefab has often been referred to as ‘architecture’s oldest new idea’." They chronology begins with the Romans in 43 AD. I push the beginning of prefabrication back to even earlier to the tents of nomads.

Animation from Wikimedia Commons