Once a dirty word in the architecture world, prefabrication is being seriously considered as an alternative construction method thanks to the focus on quality, efficiency and finish.
Introduced to satisfy the demand for fast and cheap group housing projects, prefabrication as a building concept came to be associated with low quality. Combined with a string of failures in buildings using early prefab methods, prefabrication very soon struggled to find mainstream acceptance.
However, there is growing interest in Australia in prefab as an alternative construction method with new companies specialising in pre-made housing modules entering the market and finding ready customers intrigued by the benefits.
What is prefabrication?
The Free Dictionary’s definition of prefabrication is ‘to manufacture in advance, especially in standard sections that can be easily shipped and assembled’. In practice, prefabricated components are generally made in a factory, then shipped complete to site, where they can be integrated with other parts to form a whole. Prefabrications may also be known as ‘sub-assemblies’.
In the construction industry, prefabrication can range from prefabricating components such as pre-assembled window frames, to whole modular rooms and even entire houses. Prefabrication in construction is not a new process and actually dates back thousands of years.
One of the first examples of full prefabrication for housing was created for Australia in the 1800s by London carpenter Henry Manning who designed a house for British emigrants that could be built and shipped in components, and then assembled on site. The Friends Meeting House in Adelaide is one such prefabricated building.
The Second World War also saw an upsurge in prefabricated structures with fast, efficient housing created both for the mass accommodation of military personnel as well as to replace housing destroyed by enemy bombing runs, particularly in the UK. The stigma attached to prefabrication may have come from such buildings that necessarily favoured function over form and were seen as temporary rather than desirable accommodation.
However, this is starting to change as the benefits of prefab housing become more apparent.
Closely tied to the concept of the assembly line, prefabrication also involves the use of the same processes and machines for as many applications as possible in a single controlled environment. When compared with the variabilities of constructing on-site, prefabrication can grant projects significant benefits in speed, safety and quality control.
Key benefits of prefabrication as listed out by the Prefab Australia website:
The off-site fabrication process can take place in the factory, in parallel to site preparation activities. This can reduce the overall construction period of a project significantly.
Health and safety is easier to control in a factory. For example, most of the work can be conducted at waist height, and workers know the machinery and systems of the factory.
A predetermined quality can be achieved in a factory controlled process, and the indoor environment means buildings and components are protected from climate extremes and vandalism.
There is greater cost certainty due to minimal weather delays, plus there is an earlier design freeze due to requirements of the manufacturing process.
Faster time to occupation can generate income for clients earlier and lead to lower site overheads due to less time on site.
Minimum site disturbance, tightly managed material flow and construction waste, and pre-planned assembly and disassembly can reduce the environmental impact of construction.
In communities with a shortage of skilled trade labour, the prefabricated building production line can be organised to employ less skilled labour, working under supervision.
With advancements in prefabrication technology, the ability to customise prefab homes into distinctive buildings has increased. In Australia, some prefab houses have even been created as luxury homes.
Framing products from EDGE Architectural take advantage of the prefabrication processes, and are supplied to the site pre-assembled and ready for installation. EDGE’s 150mm and 182mm structural glazed and curtain wall systems can be factory glazed, saving time and cost on-site during the construction process.