Construction and manufacturing both deliver a finished product by transforming raw materials. However, there are important differences: manufacturing focuses on large batches of identical products in controlled factory environments, while construction deals with unique projects that are built in exposed sites. As a result, manufacturing wastes a reduced percentage of the input materials, and quality control is simpler.
Prefabrication is a very promising concept for building developers, since it brings many benefits of manufacturing. Buildings are assembled from modular elements that are produced off-site, reducing the scope of work and man-hours at the project location. A controlled factory environment is also safer for the project staff, compared with an active construction site.
With a conventional construction process, all materials are delivered to the project site to be transformed into a building. However, this approach turns construction into a wasteful process:
Contractors can implement waste management practices, but some forms of waste are unavoidable even when materials are used efficiently. However, since prefabrication is carried out in a controlled factory environment, recycling and waste reduction are simplified.
When materials are used more efficiently, project costs are reduced accordingly. Prefabrication achieves further cost efficiencies by allowing automation in a factory environment, reducing the man-hours required in a project.
When the entire building process is completed outdoors, construction may be suspended due to external factors like unfavorable weather. However, this issue is minimized with prefabrication, since production can continue in a factory floor under any weather conditions.
Regardless of how a building will be used, fast construction is always beneficial for the owner:
Construction involves heavy machinery in constant movement and frequent material deliveries, while producing plenty of noise. Also, material deliveries and truck movement can disrupt traffic when a project is located on a busy street.
By moving construction work off-site, prefabrication minimizes disruption for neighbors. Although the modular components must be delivered to the project site, handling finished products is easier that working with basic materials.
3D modeling tools have a well-established role in manufacturing, but the concept is relatively new in the building sector. Since prefabrication brings part of the construction process to a factory environment, it allows automated manufacturing methods that are based on digital component models. Machine-tools controlled by CNC robots are a well known example.
Building Information Modeling (BIM) can produce highly detailed documents and specifications, but meeting these requirements in an exposed construction site is a significant challenge. On the other hand, a controlled factory environment allows improved quality and higher accuracy.
There is a common misconception that a prefabricated building is more expensive than one built with traditional methods. It is true that prefabrication consumes large amounts of resources upfront, while material expenses are spread more evenly during the project with traditional construction. However, when prefabrication is planned and implemented correctly, it reduces total project costs.
Prefabrication also involves a learning curve for project staff members, who may be used to decades of traditional construction methods. However, the work of supervisors and contractors is actually simplified with prefabrication. Consider that the design approach must be changed slightly, since the building must be specified in terms of modular components produced off-site.