Prefabricated Construction

Table of Contents

A prefabricated wall panel being installed [1]

An image of a wall panel being installed by a large crane on top of a building.

Overview 

Prefabricated construction, also known as prefab, is a type of construction that uses preassembled components to create a structure [2]. Components are built in factories off-site, then are brought together and assembled on-site. Prefabrication is slowly gaining popularity and is used in most modern construction projects to some extent. 


Prefabricated vs. Modular Construction

Prefabricated and modular construction are terms that are often interchanged and confused. Modular construction refers to construction of entire modules or units that can then interface with identical modules to create a building with identical sections, such as a hotel. Prefabrication however, can refer to something as small as a single wall panel that includes preinstalled electrical and plumbing connections. Because of this, all modular constructs are by definition, prefabricated, but not all prefabricated constructs are modular [2]. To learn more about modular construction, view the modular construction page.


Advantages and Disadvantages of Prefabricated Construction

Prefabricated construction has a large number of advantages, but also a number a disadvantages to consider [3].

Advantages

Disadvantages

  • Less waste generated
  • Can be built faster 
    • Parts can be made in parallel rather than in series
    • Construction is not limited by weather conditions
  • Lower cost
  • Better quality, tolerances, and workmanship
  • Requires less skilled construction labour
  • Easier for construction with smaller site sizes
  • Transportation
    • Risk of damage to the construct
    • Size limitations of the prefabrication
    • Cost of transporting 
    • Cost of temporary bracing for transportation
  • Requires predictable and consistent demand which is unusual in the construction industry


Types of Prefabricated Construction

Many types of prefabricated construct exist, with the primary methods being shown below [4]. The methods shown here are generally smaller assemblies, as many larger assembly types are covered in the modular construction page


Panelized Wood Framing 

This prefabrication technique combines laminated timber and plywood to create wood panels that can be as long as 72 feet. Panelized wood panels are generally used as roofing panels as they cover a large area and can be covered with a more weather resistant layer later in the construction process.

A preassembled roof panel being installed [5]

An image of a section of preassembled roof panel being installed on top of a residential home.

Concrete Systems

Most concrete in a construction project is poured and created on-site, however weather conditions can greatly affect time and availability of concrete construction, but more importantly can affect quality of the concrete. For this reason, concrete walls or specific parts such as individual staircases or elevator shafts may be pre-made and transported to the construction site. 

A prefabricated concrete wall panel with installed windows [1]

An image of a concrete wall with 3 pre-installed windows is being installed on top of a large building.

Steel Framing

Similar to concrete, steel framing is widely used in large construction projects, but is almost always completed on site. Prefabricated steel framing is becoming more common as it allows for parallel construction and no weather limitations, as well as decreasing safety risks. In addition to larger projects, some buildings can be completely made from prefabricated steel [6].

A prefabricated steel building frame [6]

An image of a prefabricated steel building structure.



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