Prefabricated housing – Part 2

The Sun Daily

Posted on 10 October 2014 

LAST week's article explored the basics and fundamentals of what prefabricated houses are all about. This week, we provide deeper insights and a clear, comprehensive picture of a prefab house, complete with floor plan, construction process and the finished product.

Quick delivery

In this day and age where time is money, speedy delivery of a house would incite a celebration for
both the developer and house buyer. For the developer it would lead to a shorter timeframe for recovering his or her investment and generating profits. The buyer in turn, receives the keys to their property faster. Says Daiwa House chief architect Kanta Tokuda:
"In the case of Japan, it takes about four months (to erect a prefabricated house) from the signing of the sales and purchase agreement, to completion of a unit (which in Japan is at the average size of 2,200 sq ft)." The processes involved include:

1) signing of SPA (sales and purchase agreement);

2) beginning of prefabrication at factory;

3) commencement of foundation work and construction;

4) assembling and erection work;

5) wood and plumbing work plus interior fit-out;

6) testing after completion; and

7) hand over.

Economy of scale is a widely cited benefit in the case of prefabrication as components and entire homes can be produced in large quantities. With prefab, there is also value in faster project schedules, not to mention fewer weather delays and more efficient use of materials. Optimisation and quality control are prefab's biggest and best features. "A primary benefit for the buyer is the predictability, which actually means less defaults and defects after the keys are handed over," shares Tokuda. He adds that the purchaser not only receives the advantage of getting his or her house fast but with a degree of surety of the outcome.

Better quality

With components and parts of the home all manufactured under uniformed control and precision calculations by machines, there is little room for defects. Where Daiwa is concerned, Tokuda assures that steel is used as beams, columns and wall frames. This provides sound stability. "Many homes in Japan are prefabricated. They can withstand the Japanese typhoons and earthquakes and are very secure."

While the metal components are treated with anti-rust and given an electrostatic coating, wooden materials are applied with anti-termite treatment prior to installation. All components are basically "fitted in" or "screwed on" using nuts and bolts. Doors and door frames are also created with much thought put into the design. People-friendly and created with safety, security and innovative design in mind, the doors prevent fingers from getting trapped.

The design of the prefab prototype house by Daiwa House in Malaysia is enhanced with accessories, appliances and fittings of premium quality. Tokuda also makes it a point to inform that the bathroom can be installed in just a couple of days. He highlights the high quality materials, cleverly designed and purposefully created fit-outs used in the modern design lavatory. The plumbing system applied in Daiwa's prefab structures are also created to stave off water leakage and such.

Smart house and green technology

Every room in the prototype house is designed with two windows that allow natural air to flow within. All windows are also fitted with elegant-looking mosquito screens. These allow them to be left open without inviting unwanted insects into the home.

The prototype house is also fitted with a solar water heater system with panels placed on the roof. The house is also equipped with unique features that help reduce electricity usage. Although all five bedrooms are fitted with air-conditioners, Tokuda says that electricity consumption is low as the house "runs" on a smart house technology system called HEMS (Home Energy Management System) that improves overall efficiency, conserves energy and saves costs, as well as the environment. "The system enables more effective energy consumption, reduces carbon dioxide emission and promotes energy savings in the home," explains Tokuda.

Moreover, the exterior walls of prefab houses in Japan are insulated to promote air circulation functions (by filling the interior of the wall with thermal insulating material and adding a dense outer layer of insulating glass wool board). There are also two coats of waterproofing applied, a primary coat to the wall's exterior and a secondary to the wall's interior. What this does is that it allows moisture to escape through the air permeating layers which also inhibits the formation of condensation. Walls of prototype houses in Malaysia have been modified to suit our climate.Quick, clever and clean ... are we now ready for prefab housing?