Earthquake Resistant Prefab Houses—Promise of a Shock-Proof Safe Home

Disasters don’t come with a phone call

Building earthquake proof houses was the last thing on Punya Ram Kawang’s mind, who woke up to 25th April, assuming it to be a day like any other, in his routined, unassuming life as a teacher in Kathmandu. But, the day was about to change his life forever.
Before clock struck twelve, a magnitude 7.9-earhquake jolted Nepal, leaving a trail of destruction, tearing nearly 1 and a half lakh houses and 1,400 schools into dust. After two days, Kawang found himself inconsolable, standing before his collapsed neighborhood, marooned in strewn bodies and broken bricks. To everyone’s utter shock, along with mortar-built traditional houses, Nepal’s ancient monuments fell like they were made of cards. Later, helicopters arrived and post-disaster housing plans materialized, but the loss of countless lives was something beyond repair.

Nepal Earthquake

Source : NDTV

Is your house at risk of quake/wind damage?

Houses crack during quake due to earth’s seismic activities. The extent of damage depends on how close the epicenter is, to the ground. A shallow earthquake can wreak massive havoc on structures. Even tsunami can take place when seabed happens to be the epicenter. Not only quakes, severe wind loads and thunderstorms can also destroy cities. Cyclone, on the other hand, is a weather situation creating a funnel-like cloud over water. Indian coastal areas are highly prone to cyclone and heavy-rain deluge. If your house is near any of these high-risk areas, it should be designed specially to withstand natural forces. Efficient engineering, to some degree, can save a house from nature’s fury. For instance, the colossal disaster in Nepal was unable to shake Pashupatinath Temple, owing its firm construction and smart architecture. As CityLab reports, “Unlike the collapsed sites…the Pashupatinath Temple isn’t very tall.”

Chile Earthquake

Source : Wikipedia

Of course, traditional high-rise construction is complicated. And truth is… most houses aren’t as rock solid as Kathmandu’s sole surviving temple. Towering height, along with many common structure problems can threaten the safety of your house when such debacle takes place. Houses with shoddy foundation, cheap mortar and unreinforced walls can be damaged easily by the whims of nature. Also old buildings with staircase or balconies preciously hanging can fall to pieces when a disaster strikes. This is probably the reason why a better and safer housing alternative demand is on the rise. Could prefabricated modular home fill the void?

Are prefab custom homes safer than traditional construction?

Often people think that prefab custom houses are flimsy and will break easily. The fear is natural. How can you trust a house that have its parts made in factory, carried in a truck and set up before your eyes overnight? Haven’t you watched the mobile homes in Hollywood movies, helplessly swirling away in hurricanes? But wait till you see how prefab houses are built.

  1. First, prefab floors are set. Generally a wood frame is assembled underneath to be attached with wall panels.
  2. Next, nails and bolts are used to attach wall panels. Windows are cut and panels coated with a protective layer before attaching the panels.
  3. After erecting the basic structure, ceiling, plumbing and electrical cabling are done.
  4. The roof is craned above and crowned on top of the house.
  5. Custom, pre-designed interiors are added along with the wall-painting, siding and cabinets.
Prefab construction process

Source : Wikipedia

So, can prefabricated building make any difference? The answer lies in load-enduring “post and beam”technology and steel caged footings which make a prefab house adapt to any weather condition and geography with ease—a trait rare in traditional Indian houses.

post and beam

Source :

Also, a house’s strength lies in where it sits—the foundation. Contrary to the widespread belief, foundation for prefab house is not done overnight. First engineers analyze the soil condition and the quake/flood—vulnerability of the site. Then they lay their hands on the basement. For instance, if you opt for slab foundation house, and desire to make it seismic resistant, floating slabs with steel support are cool. But if the soil condition is too poor, include steel-supported grade beams for maximum protection. In extreme earthquake-rated areas, a special method is followed. Here, prefab foundations are stabilized after inserting them a few notches deeper
in the earth. Then, the walls are injected with polyurethane to give them optimum strength against earthquakes and wind loads.

Proven Integrity of Prefabricated Modular Homes

Experts believe that custom prefab homes are way better than most site-built traditional houses. May be most of us haven’t even heard of prefab houses. And may be, the concept is still shrouded in rumors and myths in Indian subcontinent. But this modern housing technique has been utilized in major parts of the globe. The Federal Emergency Management Agency (FEMA) of America has already praised the clever “module-to-module” prefab construction methods. Comparing modular homes with traditional site-built houses, FEMA noted that modular houses were less affected than conventional housing, in face of 131-155mph wind speed. Not only prefabricated modular houses suffer minimal structural loss in hurricane-level winds, but prefab relief-housing also has been a smarter renovation option for many.

prefab relief housing

Source : Flickr

However, after the devastating tremor left many dead and the rest, homeless in Nepal, the need for building safe houses is rapidly growing. Prefab custom home was the chief topic of interest Safe Home Expo 2015, held in Kathmandu this year, where companies met to promote earthquake resistant homes to potential buyers.
Natural calamities are beyond control. Still, had builders taken initiative to promote safe housing before 25th April… had government aided local prefab industries to contribute a little more to build a safer environment, some lives could have been saved. Punya Ram Kawang, the teacher from Bhakatpur, would probably have saved his house from turning into a pile of rubble.
What do you do to protect your house? Tell us in the comment section below.

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