Prefabricated Architecture

Prefabricated architecture is building with parts that are made in a factory or yard away from the site and then transported and assembled where the building will stand. Those parts can be as small as a precast stair or as large as a finished room, and the method applies to houses, schools, factories, pavilions and bus stops alike. What defines it is where and how the work is done, not what the building looks like.

What is prefabricated architecture?

Prefabrication moves a share of construction off the site and into a controlled place of manufacture. The standard definition is the practice of assembling components of a structure in a factory or other manufacturing site, then shipping the finished assemblies to the location of the building. Off-site work is usually grouped into four families: component or sub-assembly systems (trusses, stairs, precast beams), panelised systems (wall, floor and roof panels, including timber cassettes and precast concrete panels), volumetric systems (whole rooms or pods), and modular systems (complete building sections).

That makes prefabrication a manufacturing method rather than a style or a building type. It overlaps with two neighbouring subjects on uni.xyz, and the line between them is worth drawing clearly. Modular design is a design principle: composing from repeated, interchangeable units at any scale, whether or not those units come from a factory. A tatami room is modular, yet nothing in it is prefabricated in the industrial sense. Modular housing is narrower again: dwellings built from volumetric modules, which is only one of the things prefabrication can produce. A precast concrete car park, a flat-packed festival pavilion and a steel-framed house built from bolted factory parts are all prefabricated architecture, and none of them needs to be modular housing.

The practical questions in this field are therefore about production: which parts are made off site, how big they can be and still travel, how they connect, and how much finishing is left for the site. Those decisions shape the architecture as much as any sketch.

A short history of prefabricated architecture

People have shipped building parts for centuries, but the modern story starts with industrial iron and glass. The Crystal Palace, designed by Joseph Paxton for the Great Exhibition of 1851 in Hyde Park, was assembled from identical, fully prefabricated modules of cast iron and plate glass. It was ready to receive exhibits in about five months, was later moved to Sydenham, and stood there until a fire destroyed it in November 1936.

In the early twentieth century the method reached the ordinary family house. Between 1908 and 1942, Sears sold more than 70,000 kit houses by catalogue. The kits travelled mainly in railway boxcars, precut framing lumber was offered from 1916, and the pieces were stamped with codes that matched the drawings, so many owners assembled their houses with relatives and neighbours.

After the Second World War, prefabricated temporary housing was used widely to replace homes lost to bombing, and its uninsulated, cold interiors left prefabs with a stigma that lingered for decades. In France, Jean Prouvé took a more inventive path, transferring manufacturing technology from industry to architecture. His aluminium Maison Tropicale prototypes of 1949 to 1951 were built for West Africa, with one sent to Niamey.

The best-known postwar experiment is Habitat 67 in Montreal, which grew out of Moshe Safdie's McGill thesis and was built for Expo 67. According to The Canadian Encyclopedia, its 354 concrete boxes were cast on site inside reinforced steel cages, fitted with windows, insulation and services on an assembly line, then lifted by crane into place.

"We can’t sustain suburbs, so let’s design a building which gives the qualities of a house to each unit."

Moshe Safdie, on the vision behind Habitat 67, quoted in The Canadian Encyclopedia

Today the vocabulary has shifted to offsite construction and DfMA, design for manufacture and assembly. The RIBA first published its DfMA overlay to the Plan of Work in 2016, giving guidance on applying the approach at every stage of a project, from brief to use.

Key principles of prefabricated architecture

Decide early what is made off site

Prefabrication rewards early decisions. Once a team knows which elements will come from a factory, the grid, the spans and the service routes can be set to suit them. Factory tools such as jigs, cranes and conveyors make production faster and more precise, and indoor work keeps weather out of the process.

"As much as DfMA is a technical process, it is also a philosophy that should be seen as an extension or evolution of the designer’s ordinary way of working"

RIBA, DfMA Overlay to the RIBA Plan of Work

Size every part for the journey

A prefabricated element has to be lifted, loaded, driven and lifted again. Large volumetric sections can raise transport costs and need heavy cranes and precise handling on arrival, which is why many teams prefer panels and frames that pack tightly. The UNI Editorial journal on tresarquitectos' Prototipoextend in Rionegro, Colombia shows the logic at house scale: gabled modules on a repetitive steel frame are fabricated off site, lifted and set on one, two or three concrete columns, and each added column extends the plan.

Design the connection as carefully as the component

Factory precision is only useful if the joints on site can receive it. Bolted, screwed or clipped connections also decide whether a building can later be taken apart. Site Frames, by Qianqin Zhou, Te Li and Qingyun Xu, is a prefabricated bus stop built from a transparent frame system with an alternative fabric unit, and its vertical parts rotate to give the shelter different degrees of intimacy.

Leave room in the frame

A prefabricated structure can be planned to grow. In Supra-Simplicities' MOM House in Kaohsiung, featured by UNI Editorial, a prefabricated steel grid replaces an ageing concrete home, eight modules run along one axis, and one bay is held back for utilities and future growth.

Plan for disassembly

The same logic that makes assembly quick can make dismantling clean. Students from Hochschule Kaiserslautern built the Gabonsa Pavilion in Innsbruck, featured by UNI Editorial, with no adhesives and no permanent fixings: every connection is a screw that can be backed out, and the materials come from an ordinary building-site supply chain.

Prefabricated architecture on uni.xyz

Members approach prefabrication from two directions: built work documented by UNI Editorial, and competition proposals that test kits, frames and factory-made units against hard briefs such as disaster recovery and seasonal pilgrimage.

ALAS Alarcon Linde Architects' paint factory for Hemmelrath Technologies in Erlenbach am Main is the most complete built example in the collection. It is made almost entirely of cross-laminated and glue-laminated timber, with concrete only where fire rules require it, across 2,820 square metres of production, laboratory, logistics and office space. Three interlocking volumes can grow through pre-planned extensions, and the whole building is designed to be taken apart and reused by material.

Fold Bunk, by Kaya Liffler and Lorenz Hahnheiser, is an Editor's Choice entry in the Encamp competition. It is a prefabricated kit whose components double as transit packaging and finished building elements: the dwelling travels as a tight rectangular package and unfolds into a timber A-frame through a sequence of floor, wall, roof and structural parts. It is a modern answer to the Sears kit, compressed for the back of a truck.

Also from Encamp, A Shelter Made of Scaffolding by Yuechuan Jin, a shortlisted entry, takes the most prefabricated object on any building site and turns it into the building itself. Rooms, terraces and stairs occupy chosen bays of a repetitive steel grid, and the rest stays open.

Disaster recovery is a recurring brief. Forgiveness housing by Amin Mohsen Rikani, entered in the Reborn competition, proposes prefabricated industrial units built before an earthquake from modules that can be separated and reinstalled as needs change afterwards. The Silk Road Housing by Studio Projetos BR, an Editor's Choice entry in the same competition, asks for a shelter that is fast, efficient and agile in its assembly, and that can then become a permanent home.

At the smallest scale, Minima by Akansha Pandey, an Honorable Mention in the Mobitecture competition, is a compact home for a family of four built around an easy assembly and disassembly process. For a cultural building, Postindustrial Lighthouse by Katarzyna Chłodek, entered in the Proximity Island 2019 competition, multiplies and projects prefabricated modular boxes to make a gallery that draws visitors through it.

Finally, House factory by Jana Starcevic, an entry in the Bauhaus Neue competition, goes back to the roots of the idea: house prototypes made available to everyone, with anyone interested invited into the making.

"Bauhaus was about design for everyone, philosophy was encouraged by mass production and not restricted by it."

Jana Starcevic, House factory, project statement on uni.xyz

Challenges and future directions

Prefabrication still carries old problems. Transport sets hard limits on size, and large sections need cranes and accurate handling. Tolerances matter: parts made to the millimetre must meet foundations and neighbouring work built less precisely on site. A factory also needs a steady pipeline of orders to stay efficient, which favours repeat clients and standard products over one-off designs. Then there is reputation. The cold, uninsulated temporary houses of the postwar years taught a generation to read prefabricated as cheap, and designers still have to argue against that memory with quality.

The most promising direction links prefabrication with reuse. If parts are made to be assembled, they can be made to be recovered. The essay Assembling the Ruin by Nicolas Rodriguez treats architecture as a reversible system of parts, studying nineteenth-century timber barns around Lake Llanquihue in southern Chile that German settlers built with joinery and no nails. Taking such a building apart, the essay argues, is a way to understand it, and a first step to building again.

Digital tools make this easier to manage. A model that knows every component can produce cutting files, assembly sequences and, later, a parts inventory for dismantling.

Prefabricated architecture for students and designers

Prefabrication suits student work because it forces you to show how a building is made, not only how it looks. Strong thesis angles include a flat-pack shelter whose packaging becomes part of the building, a timber cassette system for school extensions, a demountable market hall, or a study of a local craft that already works like a kit. Draw the joint at full scale, show the delivery and lifting sequence, and say what happens at the end of the building's life.

Open briefs on uni.xyz competitions regularly reward this kind of thinking. For related reading, see construction technology and wood construction.

Frequently asked questions

What is the difference between prefabricated and modular construction?

Prefabricated construction covers any building part made off site, from a single precast beam to a whole room. Modular construction is one type of prefabrication in which complete three-dimensional sections are built in a factory and joined on site. All modular buildings are prefabricated, but most prefabricated buildings are not modular.

What are the main types of prefabricated building systems?

The usual groups are component systems such as trusses and precast beams, panelised systems such as wall and floor panels, volumetric pods, and complete modular sections. Many buildings mix them, for example a precast frame with panel walls and a factory-made bathroom pod.

Is a prefabricated building temporary?

No. Some prefabricated buildings are designed to be moved or dismantled, but many are permanent. The Crystal Palace stood for more than eighty years, and Habitat 67 is a protected landmark in Montreal.

What was the first prefabricated building?

There is no single first. Builders have prepared parts in advance since ancient times, but the Crystal Palace of 1851 is one of the most visible early examples of industrial prefabrication in iron and glass.

Why do architects choose prefabrication?

Factory production allows tighter quality control, work that is not stopped by weather, and shorter time on site. The trade-offs are transport limits, the need for cranes, and design decisions that must be fixed earlier than in conventional building.

References and further reading

• Prefabrication, Wikipedia
• The Crystal Palace, Wikipedia
• Sears Catalog Home, Wikipedia
• Jean Prouvé, Wikipedia
• Habitat 67, The Canadian Encyclopedia
• DfMA Overlay to the RIBA Plan of Work, Royal Institute of British Architects