If asked a question: Can one wait for years and years to build another building like the Taj Mahal? The answer by many would be no, saying — “who has the time and patience for it, and eventually, it will cost a bomb.” Any building development is about speed and efficiency in construction and ensuring the design techniques are in precision at the site with minimum human errors. It may seem to test the greatest virtue of humankind and may require constant supervision.
The globally trending technique of Pre-fabrication is an example of being the new fab these days, which helps to reduce the time, increase work simultaneously and provide better precision, minimising the error or rework. Many assume that this trend emerged in the late 20th century, although it dates back much further than one can imagine.
Before diving into the history, let us take a look at what Pre-fabrication or Pre-fab means. The conventional method of any building is transporting all the raw materials to the site and seeking skilled labourers and various parties required for the process. Prefab is a method that allows several building elements to be built off-site in a factory or at a workshop as per the design requirements, transported to the site for fit-out or assembly. They can either be in custom sizes or standard sizes for elements such as walls, floors, roofs, sometimes windows and doors together.
Only one needs to construct the foundation at the site. The building components can be transported through packaging or partially assembled, placed at the site through a crane and minimum skilled labours. The theory behind this method is similar to the construction of ships, aircraft, all kinds of vehicles and machines where their parts are manufactured elsewhere and assembled somewhere else.
Indeed, it is a building system revolutionising the industry through:
- Rapid speed in construction by saving time
- Cutting down the construction cost by reducing the need for formwork, shuttering and scaffolding prices, and labour needed at the site.
- Solutions provided towards the shortage of locally available building materials and skilled labours, lack of power.
- Able to be built throughout the year without being affected by the varying weather conditions.
- Lower carbon footprint and low environmental impact by reducing the emissions, minimal waste and inspection
- Quality control
- Flexibility in disassembles and assemble, movement around different sites.
- Allows versatility in structural design with an infinite number of possibilities.
The Umbrella of Pre-fab Construction
A glimpse of different kinds of building systems that fall under Pre-fab, though they belong to the same family, they have few characteristics that set them apart.
Often referred to as Kit-homes or 2D panel homes which are built-in and then delivered to the site for assembly and fit-out in construction. Wood / Timber Framing panels or long pieces of frames built of laminated timber, sandwich panels with insulation, concrete panels or pre-cast concrete blocks are few building components of this type of system.
These are 3D modular components built almost entirely in a workshop or factory and delivered to the location for final installation with finishes for walls, floors and ceilings and delivering the consistent quality designed with the same codes and standards as the conventional building. They are units that are self-sufficient to form complete buildings without the need for an additional superstructure.
Shipping containers are the best example of this kind of system. They do come in standard sizes and are restricted to the size of a transport truck but can provide options for being customised.
Hybrid Building systems
It is a combination of the panel and modular type where there are size constraints or site challenges. For example, in any pre-engineered building, a steel framing structure is with a steel skeleton fabricated at a factory and freighted to the site for assembly like a giant erector set.
The Early Days of Pre-fab
The prefab building system dates back as far as the Mesopotamian civilisation of the 1600s. The first-ever known modular wooden panel house was shipped by a boat across the Atlantic Ocean for colonial American fishing men, who had recently moved from England and wanted their homes built with trusted English construction methods.
In the 1800s, during the California Gold Rush, mining had boomed at a rapid pace, thus increasing demand for housing. More than 500 preassembled homes were built in factories in New York and then shipped across to California. Architects, Engineers and various Inventors started exploring different ways of developing the technology using cast-iron, concrete, wood and other building materials.
With this revelation, a milestone in 1889 was when the Eiffel Tower was built, assembled out of pre-fabricated iron elements in Paris, and had significantly cut down on the cost of construction and the labour required for the iconic structure.
“The Eiffel Tower assembly happened at a record speed of two years, two months and five days.”
In 1897, E.F. Hodgson opened a manufacturing plant in Dover, Massachusetts and developed a catalogue from which they sold modular homes across the country. Soon followed by Chicago based company Sears, Roebuck and Montgomery began shipping hundreds of thousands of modular homes over the next few decades and sold over 75000 homes.
The Carry-forward into the 20th century
In the years after, it became clear the efficiency of this construction method and its customisation flexibility. It expanded from homes into commercial projects, and consumers demanded more elegant modular buildings, complex structures and amenities. Many recreational vans started converting into classrooms or mobile offices; some schools, hospitals, offices and other businesses used portable buildings to expand their spaces. Pre-fabricated buildings helped to suffice the surge in demand for housing for post-World War II soldiers who returned to start their families.
Few notable milestones can be seen below:
In 1917, the famous US inventor Thomas Edison emerged to build homes out of cast-in-place concrete. Although it may not have met the success required, these ideas did pave the way for the current innovations and affordable 3D-printed housing. An example can be seen by the Chinese company WinSun Decoration Design Engineering, constructing a set of ten single-storey 3D printed homes that can be produced in under 24 hours.
In 1930, Buckminster Fuller began developing his vision for a metal-domed home—Dymaxion—that could easily be disassembled and transported and reassembled at the site.
In 1935, A ‘luxury home on wheels’ was developed in the shape of Wally Byam’s Airstream Clipper in an iconic silver-bullet form.
In 1947, drawing inspiration from Henry Ford’s assembly line of production, developer William Levitt created Levittown in New York, Pennsylvania, New Jersey, Maryland and Puerto Rico. He used a rapid-construction process where 750 sq. ft. could create Cape Cod homes in 16 minutes.
In 1976, Moshe Safdie’s Habitat 67, one of the pavilions presented at the World Expo in Montreal, consisted of 354 modular units stacked to form 148 residences.
In 1977, Architect Zvi Hecker came up with the Ramot complex in Israel, a mixed-use development with amenities like shopping, educational services, courtyards, walking paths, parking, and modular dodecahedron apartments that appeared like beehives.
In 1996, IKEA and Swedish construction company Skanska teamed up to create BoKlok houses, prefab sustainable mini-homes in Sweden, Norway and Finland. They were in the form of blocks with terraces making homeownership affordable with modest incomes.
“Architect Frank Lloyd Wright praised modular structures for their versatility surging the popularity of this FAB.”
21st Century and Beyond
Prefabs have so far been used for where on-site construction is time-consuming or constricted, used in large-scale affordable housing, factories, etc. Now they are being used in metros, public infrastructure development.
Large construction project developers have been making a shift to prefab structures since the pandemic-related lockdown, owing to the unavailability of the labours and materials and maintaining the social distancing norm at sites. Many COVID-19 facilities are building using prefab methods like a 400-bed medical facility at Kasargod, Kerala, made by Tata projects where the material manufactured at Jamshedpur, Jharkhand transported by trucks for assembly.
In 2003, LOT-EK mobile dwelling units with retractable and extendable modules were created by converting shipping containers in South Africa, Holland, New York, California and Arkansas. It comprised townhouses, apartments, dormitories, single-family units and live-work lofts catering to different masses.
In 2016, The world’s tallest modular building, 56 Leonard Street, colloquially Jenga Tower, is a part of residential and commercial 32 storey pre-fabricated apartment units stacked like Tetris blocks.
Due to the COVID-19 pandemic, many people started seeking for larger homes or second homes, which need to build cheaper, more flexible, faster and involving fewer parties during construction, in turn, more predictable building methods that can meet their needs. Also, due to restricted transport facilities, many people realised they disconnected from the food production, which happens farther away even than the suburbs.
Architect Chris Precht and his partner Fei introduced a new housing concept for the city dwellers as a sustainable way of living, a skyscraper in a pre-fabricated A-frame timber modular structure, Toronto TreeTower, where the modularity helps in different configurations, and they can produce their food through vertical farming.
The Downside of Pre-fab
However, every coin has two sides, so, against these advantages, one should see the downside too in this building system. A few of the drawbacks are:
- Hidden costs of transporting these sections and lifting them into positions as they may be fragile to handle.
- Challenge is for joints to be watertight and precise as there can be chances of leakage through.
- At the factory level, increased production volume required to cater to the affordability of the pre-fabrication, in turn, may increase the initial capital costs.
- Requires measurement of precision from handling to positioning on site.
- Local employment is affected as precisely skilled labourers are required for the installation of the job.
- Require immense cooperation between project parties like architects, engineers and manufacturers.
As time passes by, it may get further clarified about the role and the benefits of using the Prefab building system in building the new constructions. While building modular may not be for everyone, it remains one of the most cost-effective solutions for limited space, and timelines and budgets are tight. From shipping housing across the ocean to assembling the iconic structure of the Eiffel Tower, this fundamental building technique has stood through tested times and is with a bright future. The emerging robotic technology will help boon the trend further.
References
Video, R. et al., 2021. History of Prefabrication: Ancient times to today [Video]. Redshift EN. Available at: https://redshift.autodesk.com/history-of-prefabrication/ [Accessed September 22, 2021].
www.modular.org. (n.d.). The Surprisingly Long History of Modular Construction. [online] Available at: https://www.modular.org/HtmlPage.aspx?name=MA-oi-History-of-Modular.
JElitzer (n.d.). ModularHomeowners.com. [online] ModularHomeowners.com. Available at: https://modularhomeowners.com/do-you-know-the-difference-between-prefab-and-manufactured-homes/ [Accessed 22 Sep. 2021].
Ecoliv. (2017). Types of Prefabricated Buildings. [online] Available at: https://ecoliv.com.au/latest-news/types-of-prefabricated-buildings.
