We are well aware of the saying “home is where the heart is”. This popular saying shows how emotionally involved a person is with their home. Thus it is only natural to be a little stressed out when one commits to build a house. Stress is common not just because house is an emotional decision but also because to many people it is an investment for generations. What materials to use? How long will it take? How much will it cost? Can the contractor be trusted? And many questions similar to these are sure to crop up in one’s mind. Most of our households function with hard earned money sent as remittance from abroad. And we spend a bulk of that money in building a concrete block that we call home. While conventional RCC building is the norm, they come with a hefty price tag and take time to build. A new approach of building houses called prefabricated houses (also called prefab houses) is on the rise and it stands on the grave of the limitations of traditional building process.

What are Prefab Homes?

A prefab house is a building that is manufactured and constructed using factory made components or units that are transported and assembled on site to form the complete structure. Assemblies and sub-assemblies are done on the site where the building is to be placed. The construction of prefab houses is done with the prefabricated building materials like aluminum, steel, wood, fiberglass and concrete.

These houses are planned in advanced which leads to less wastage of materials and less rework which means they are environmentally friendly as well.  Prebuilt homes, however, do require more material in their construction than non-prebuilt homes because they have to be reinforced for delivery to the site. The quantity of extra materials depend on the expertise and efficiency of the builder which is generally 10-20%. But one should always understand that the extra material is used in construction and reinforcement rather than as wastage as in conventional building process.

Building process of Prefab homes:

Prefab homes as mentioned earlier are built in factories. Factory production of houses require attention to details in manufacturing process. Skilled manpower and regulations are strictly followed to construct houses. Prefabrication can be done to different degrees, depending on how finished the house has to be when delivered on-site. Modules and elements (also known as panels) are the two major options in construction. A module is made of different components, typically prefabricated elements that serve both as structure and as functional items.

After preliminary works like site selection, design, budgeting, contracting etc. are done, the factory starts to build components for the house. The materials like beams, columns, walls are always the same. That is one of the reason that these houses can be trusted. The builders will have a lot of experience owing to the fact that they build the same thing all the time. This doesn’t mean the designs need to be monotonous for every construction. The opposite is actually true. In absence of load bearing walls like in case of RCC houses, designers have more playing ground.

Machines are used to build beams and columns with precision. Then they are fitted with wall panels. Finally interior sections with piping for electrical connections and plumbing is done. The components are then transported either as modules or as panels to the site where they are to be placed. Modules come with ready-made floors so they can be directly positioned on leveled grounds. Usually pile or post foundations are preferred to establish an air gap between bottom of module and ground. These type of foundations are suitable for most soil types and are economical as well. Modular houses can be placed on slab foundation as well but slab foundations are generally more expensive.

Also see how an aircraft wing is manufactured.

Advantages of Prefab Housing:

• Faster Construction: Prefab housing just need to be transported and then set up in location which takes considerably less time than traditional masonry or wooden houses.

• Less labor: In traditional builds several subcontractors like electrician, painters, and plumbers are needed and work of one depends on work of another. This is not the case in prefab housing.

• Flexible Size and aesthetics: Design layout and size can be customized as per requirement.

• Energy Efficient: The way prefab homes are built, the materials they use, and the airtight construction combine to create a highly energy efficient space that can reduce ongoing utility bills.

• Acoustics: Prefab homes have much better acoustics because each module in a prefab house is a separate construction. In case of traditional houses floating floors are required to improve acoustics.

• Lower risk of damage: Theft of construction materials like bricks and tiles are common in traditional building process. That risk is minimized in prefab constructions.

• Less waste: As mentioned earlier, there is much less wastage of materials because the construction are done in factories under strict planning and supervision by professionals.

• Economical: Contrary to popular beliefs, prefab homes are cheaper than traditional buildings. The rate of building 1sq ft. of RCC building is NRS 3,500 while for a prefab house is in the range of NRS 1,600-NRS 2,200.

• Strength: Because prefab homes must be built to withstand transportation by truck, the interconnected design of these homes provides a rigid system that in most cases is as good as or better than conventional house framing.

Downsides of Prefabs:

Prefabs like anything else are not perfect by any means. It is worth paying attention to the following downsides.

• Transportation: The logistics of transportation can be an issue which obviously adds to the price of home. It can also be challenging to transport prefabs into crowded cities with overhanging walls and remote locations with difficult terrain.

• Image Problem: Despite all these advantages we cannot downplay the perceived value of such houses. The public perception is obviously biased towards RCC buildings. This can be of concern in reselling the property. People have a stigma that prefab homes don’t last long and are weak. You and your selling agent may have to spend time explaining the prefab construction process to potential buyers. 

• Lower built quality: As in case of anything, there are lower-end manufactured homes which compromise on built quality to achieve affordable prices.

• Long-Term Value: Prefabs typically depreciate quicker than conventional buildings. Due to a relatively shorter economic life, buyers are likely to offer less attractive terms. Traditional builds are sold for more than their original purchase.

The disadvantages obviously don’t hold good for high end products. But the discussion of prefab homes is relevant in the first place because of its lower price. It is also equally important to not associate prefab with just affordable housing which can mislead people into thinking that it is only suitable for small projects. Public needs to understand that prefabs are all purpose construction which can be used to build offices, hospitals, dormitories, shops and so on.

Prefab in context of Nepal

Regardless of being cheaper, safer in times of earthquake, fire resistant and aesthetic, people have still not completely bought the idea of investing in prefab housing. Businesses involved in prefabs report that while the interest in learning about prefabs has grown considerably after the 2015 earthquake, individuals rarely approach to actually build prefab houses. The Demand of prefabricated houses is in nascent stage in residential sector because of lack of product awareness.  NGOs, INGOs and government institutions have shown noticeable interest in this technology owing to its advantages (easy to transport, lightweight, fast to set up, cheap).

But because of its association with disaster relief programmes people have developed another incomplete view that prefabs are just affordable temporary housing. This can quite noticeably tarnish the image of prefabs. Prefabs are used extensively to craft luxurious houses as well.

  Prefab is a new technology to Nepalese society hence it is only natural to be under scrutiny and speculations. It is true that commercially promoted ideas should be taken with a pinch of salt because they do not consider the time needed in import and supply of raw materials as well as skill.  Shift of investment away from the targeted population when non-native technology was applied on mass scale was seen in Manjil and Bam in Iran in 1990 and 2003 respectively. The way forward should be to focus on designs which are sensitive to the lifestyle of people by incorporating locals and local technology. Proper advertisement and information should be passed down to common people in order to draw their attention towards prefabs.  Moreover, for people to believe the buildings are safe, it is crucial that they oversee the construction themselves and are satisfied. No disrespect to the contractors but if you invariably choose a factory made vehicle over the one made in a local workshop, there is no reason you can’t do alike for houses.

Also check out this Wikipedia link to learn more about prefab homes https://en.wikipedia.org/wiki/Prefabricated_home