There was a time when the word house conjured an image of brick and concrete. But keep ing with the changing times, people have begun to increasingly opt for prefabricated houses, which were mostly popular only in the western countries until two decades ago.It is believed that it was in the early 90's that the prefabricated houses first entered the Nepali market. Today many people wanting to construct villas, site offices, extensions, dormitories, workshops, and factories are opting for prefabricated houses.

The foundations of prefabricated houses are generally constructed in the workshop of the manufacturing company, and then assembled at required site using steel, wood or metal structures. "Steel and metal ayout dominates wood in prefab houses as wood is costlier," says Nilmani Sapkota, technical director of Himalayan Prefab Pvt Ltd, adding that prefabricated houses are fast to install, look more elegant, easy to modify, environment friendly and affordable.

Advantages of prefabricated houses are many. They are affordable than regular homes as they can be completed in a few days which means less money spent on labour and construction costs. The cost depends on the layout of the house and the quality of material used. The cost of material ranges from Rs 950 to Rs 3,500 per square feet. Many organisations are opting for materials within the range of Rs 1,000 per square feet. The set up time depends upon the area, like installing a house on 500 square feet takes 10 to 15 days. According to Sapkota, all the interior work and most of the exterior work is completed before the structure is even set up. Wiring, plumbing of prefabricated houses is different than that of regular houses as the former needs special designs and software to carry out the task.

Adding to the list of benefits of prefabricated houses is that they are also environment friendly.
According to Padam Bahadur Shrestha, owner of Bira furniture, setting up a prefab house requires less use of heavy equipment and construction vehicles which release harmful smoke and fume into the air. In addition, fewer materials are wasted on pre-fabricated homes since manufacturing is carefully and precisely done. Moreover, those opting for prefab houses are free from problems of termite infestation and seepage of moisture.

"The concept of prefab house is novice for residential purpose, but they can be full size luxury house," says Sapkota, adding that people are not opting for residential as they feel it is not secure or durable enough.However, the mass majority is unaware that prefab houses are also designed to easily withstand earthquakes of eight rector scale and are even water and fire proof if expanded polystyrene (EPS) materials are consructively used.

According to Sapkota, the materials used for the construction vary from company to company but most popular materials used for roof and panel are EPS, polyurethane and rock wood panel. Similarly, aluminium allay frame with wall panel are mostly preffered for the door and UPVC for the windows. For ceiling, gypsum boards are generally used. Likewise, sliding doors and windows are mostly used in pre-fabricated houses, as they are easy to handle and relocate. If done by skilled workforce and with proper handling, pre-fabricated house can be relocated five to 10 times without damaging the structure.

The life span of prefab houses depend upon quality of material used but all houses have warranty of 15 to 35 years.
Pre-fabricated house can be up to three-storied. The materials used for prefab houses are imported from China and Germany.

source: The Himalayan Times: Property plus (2011),"Going Prefab from Concrete", The Himalayan Times, 22 Jan 2011