Prefabricated Structures

Prefabricated Structures- An Introduction

The use of prefabricated technologies is not a new thing. In fact, prefab technologies have long shaped the construction sector of many advanced nations. Today, these technologies are embraced by many builders and realtors in developing countries too. Before we delve further, let us begin by understanding what prefabricated structures or prefabs are. Prefabs are buildings whose individual construction elements or components like floors, walls and roofs are made in a factory, a manufacturing plant or in a factory-like setting in advance, and only then transferred to the construction site or worksite for assembly. In certain cases, the components are also fully or partially assembled in the factory or plant before being transferred to the site. In industry, prefabs are made using a variety of prefabricated structure materials and are popularly known as Pre-Engineered Buildings (PEBs).

The Two Stages of Prefabrication 

The construction of Pre-Engineered Buildings (PEBs) begins with the structure drawing. The structure design engineers after in-depth observation & analysis prepare the drawing and refer it to build the structure as per the relevant building codes and approved Quality Assurance Plan (QAP), while adhering to the client need & budget.

- First Stage: Components are manufactured in a factory, a manufacturing plant or in a factory-like setting, which is not the final location of construction.

- Second Stage: Components are shipped and the structure is erected in the final location of construction.

Advantages of Prefabrication- Technical, Economic & Sustainability Merits 

Realty developers who are keen on adopting modern construction techniques to boost their works and compress delivery time-frames often favour prefabrication to the traditional ‘brick and mortar’ construction model while building permanent, semi-permanent or temporary facilities, including construction facilities, apartment blocks, healthcare camps, office spaces, evacuation centers, schools, colleges, etc. Time being money when it comes to building structures, prefabrication can often help in reducing the overall construction time and lend better resilience and quality to the building. To put simply, prefabrication is the best way for economizing time, effort, wages, and resources utilized in civil construction.

Prefabricated Structures can be considered advantageous for many good reasons, such as:

• Precision: Such structures being made using self-supporting ready-made components reduce the need for formwork, shuttering and scaffolding, also giving factory precision to the components built. This is not the case with conventional construction methods.

• Speed: Building anything from the ground up is time consuming. Fast turnaround is an advantage of prefab structures that are easier to erect and can be constructed in much less time.

• Safety: Prefab structures made using durable materials can withstand the strongest of winds and earthquakes. As natural disasters continue to rise, prefabs are a smarter choice for constructing buildings, especially in disaster prone areas.

• Quality: Prefabrication is always in demand as it minimizes the on-site congestion of sites, i.e., site disturbance, also helping one attain better quality control through factory assembly line setting. Besides, better thermal and sound insulation is witnessed in case of prefab structures.

• Cost Efficiency: Any site where skilled labour, space and other resources are readily available can be transformed into a prefabrication site, which greatly reduces the total project cost. Cost also gets reduced as there is less wastage of construction material with prefabrication as compared to other traditional methods.

• Technology: Latest fabrication technologies coupled with emerging CAD is expected to lend a further edge in the field of modular construction. 

Apart from various cost and construction benefits, prefabricated structures also come with many environmental and social benefits. Especially, climate change that has intensified natural calamities in recent years have made prefabrication much preferable as an alternative method of construction because of its resiliency. Prefabs prove to be more affordable and durable than replacing damaged buildings in hostile post-disaster conditions. Therefore, home owners and construction companies of coastal areas that are more prone to hurricanes or tropical storms prefer these systems to minimize the effects of adverse climatic conditions on the infrastructural landscape and greatly improve community resilience in the process.

Environmental Impact- Prefab Versus Conventional Structures

Traditional construction methods used for erecting cast-in-situ buildings consume natural resources in excess, also leading to serious green-house gas emissions. Modern research also underlines that Prefab Versus Conventional Structures constructed at the same time and even in the same location show a marked difference in their carbon emission levels. Even when one considers the entire life cycle of buildings, there is minimal impact of prefabs on environmental damage as opposed to traditional cast-in-situ buildings.

Uses of Prefabrication

Apart from being utilized in the construction of large buildings, prefabrication is also used for building prefab concrete and steel sections in structures, mostly in cases where one building element needs to be repeated multiple times. Prefabrication comes handy in constructing apartment blocks and housing developments with repeated housing units, office blocks, factory buildings, storage houses, etc. Glass and steel sections are often prefabricated off site for use in the exteriors of huge structures and buildings. Prefabrication is also largely used for building mobile phone radio towers, aircrafts, etc. 

Prefabricated Building Materials

With evolving technology, definition of modular construction too has attained a new meaning. Today, different materials go into the making of prefabs, which mostly are decided by the manufacturer. Manufacturers take note of specifications and budget of the customers before beginning any prefab project. Primarily, they use the following materials for prefabrication: 

• Steel: Modern construction relies on the versatility and strength of steel. Though its weight and rigidity make it a bit difficult to mould, steel can be shaped into any form with the right skills, technologies, and tools. Steel makes prefabs durable and fire-resistant. Besides, steel-framed modular structures are easier to assemble than the ones made of wood.

• Wood: Wood being lighter than most materials is often chosen for prefab construction. Any framework can be crafted from a piece of wood. Sustainable species are usually preferred, which can even be reused and recycled into other materials. Medium-density fibreboard (MDF) and particle boards made of recycled wood are ideal for framing. Wood-frame structures made of durable wood are chosen to build structures that are expected to last thousands of years.

• Concrete & Cement: Concrete plays a valuable role in prefab construction. Processes like manufacturing, moulding, drying, and curing steel-reinforced concrete or cement sections can be done in a factory setting where factors like ambient humidity and temperature can be easily regulated as per the need. Concrete used to engineer the core of a building can lend maximum support to the rest of the structure with its inherent strength.

Common Prefabricated Systems 

Underlined below are the most common types of prefab systems used in the construction industry:

• Panelized Wood Framing: Prefabricated Systems designed in the form of Panelized Wood Framing can make roof construction a safer, time saving and easier affair. In such cases, laminated timber is utilized for making long, sturdy pieces of frames, which are then covered either by plywood or board roof decks. 

• Sandwich Panels: For maximum structural stability, Sandwich Panels fabricated from thin facings of materials are often used. Facings made from materials like concrete, plywood, or stainless steel (SS) are used, which are then stuck to an insulating core. The core can be constructed of foam, rubber, paper or even textile (cloth). 

• Steel Framing: Prefab panels engineered from durable steel has become a prefabricated building material of choice for constructing commercial and residential structures.

• Timber Framing: This type of framing though is not too common a practice used in India is widely used in building structures in other countries. Timber framings that are casted in factories or factory like settings are often used in building timber homes.

• Concrete Systems: Concrete fragments engineered in the factory instead of being built on site can help in improving the look and feel of a building. The process also proves to be quite time saving.

• Modular Systems: Here, the entire building structure is erected from factory-constructed assemblies and units that are hauled to the final construction site. These units made in various sizes and specifications are then connected to the prepared foundation.

Industry Applications

The lean construction mode of prefab is majorly utilized in the following areas:

• Airports

• Commercial Buildings

• Engineering & Manufacturing

• Infrastructure

• Automobiles

• Healthcare

• Power

• Textile

• Retail

• Warehousing & Logistics

Prefabricated Structure Specification 

• Foundation & Plinth

• Structure

• Flooring System

• Walls

• Roofing System

• Windows & Doors

• Mechanical, Engineering & Plumbing

Prefabricated Structure in India/ Prefabrication in India

Though many countries like Japan, USA, Europe, and Canada began transforming their infrastructural landscapes with prefabricated structures ages ago, prefabrication as a process gained ground in India only in 1950 when Hindustan Housing Factory was established with the aim of solving the housing problem created in India in the face of the refugee influx from West Pakistan. The company, the pioneer of prefab structure design and technology in India, was the first to throw light on the fact how prefab technology could generate instantaneous low-income housing solutions as compared to traditional brick-and-mortar structures. The target market which was earlier only the low-income group soon expanded and included hotels, up-market residences, commercial complexes, public utility buildings, etc.

Today, prefab structures, though popular in the civil construction sector of other countries, are still not a widely-adopted means of building structures in India. The method has not managed to attain the confidence of skeptical Indians, mainly because they are not completely aware of its benefits and simply see it as a low-income housing alternative. For many others, prefabrication conjures up images of unrealistic homes that come with unexpected risks. No wonder, the market of prefabricated buildings almost stands on the sidelines, accounting only 1% of the $100 Billion Real Estate Market of India.

The Takeaway

Prefabrication will soon be one of the finest examples of technological evolution, innovation & excellence.

With the rising population in India, many Indian construction companies, realtors, and builders have begun responding smartly to the need of the hour by gravitating towards prefabrication when taking construction projects related to building housing societies, malls, hospitals, schools, etc. The mission is to break the confines of traditional building methods, keep pace with the global construction industry, embrace innovative construction materials and construction techniques, and offer revolutionary prefab building solutions with many added benefits. According to many recent reports, the next decade will see prefab construction taking a giant leap in India supported by several reforms initiated & announced by the Indian Government and we all are more than optimistic.

FAQs: Prefabricated Structures

Q. What is a PEB or a Pre-Engineered Building?

Ans: A PEB or a Pre-Engineered Building is a building whose structural elements are constructed off-site as per a predetermined structural drawing. The elements are then transported to the final location of construction for installation. 

Q. What is the average time taken to construct a prefab?

Ans: The construction procedure of a prefab is quick, and the time taken for construction is almost 30 to 50 percent less than a conventional brick and mortar structure.

Q. Are steel framed prefab structures safe in lightning?

Ans: Yes, steel framed prefabs are safe in lightning and score high in terms of protection.

Q. What is the price of a prefab building or structure?

Ans: The price of a prefab may vary depending on the building design, application, aesthetics, and technical configuration. 

Q. What is the longevity of a prefabricated structure?

Ans: Prefabs are designed to last for years. The exact life of a prefab depends on its technical specifications.

Explore Prefabricated Structures at Tradeindia

Tradeindia networks with specialist providers of Prefabricated Structures who contribute significantly to India’s infrastructural development and whose products are a blend of innovative ideas and cost-effective construction technologies. All the players have track records of providing innovative yet affordable housing options and keeping up with tight deadlines.