New flood-proof housing designs

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1 Araya Chientachakul New flood-proof housing designs Bangkok s unprecedented prolonged floods in the second half of 2011 have spawned many new and innovative flood-proof housing designs. With an estimated 25 to 30 per cent of new homes built on the city s northern flood-plains, developers are quickly adapting housing designs to better withstand annual flooding by minimizing disruption to occupants daily lives. Asia-Pacific Housing Journal 44

2 Innovative flood mitigation ideas Developers have primarily designed three types of homes to address the issue. The most basic design is raising the ground floor level of each house and incorporating integrated flood protection systems. Other developers have created designs that eliminate all basic living on the structure s main floor. Amphibious houses that are able to float when floods arrive are the third type of design forwarded by Thai architects and developers. While each of these new designs will result in higher costs, last year s floods seem to have stoked the demand for these flood-proof homes. Living with nature Thailand has long lived with annual floods particular during rainy seasons when flood waters routinely drain naturally along the rivers and low-lands to the ocean. In the past, many people lived in homes that were built to withstand annual floods. Rather than fight nature, these homes were either built on stilts or were raft-homes that would float when the annual floods came. However, with rapid urbanization and industrialization, the country began filling-in canals that acted as natural drainage areas for flood water into roadways. Moreover, the construction of massive dams and dikes created an aura of complacency among the citizenry, who believed that they were fully protected from any future floods. The unprecedented 2011 floods have however developed fears that many consumers may no longer wish to purchase homes along Bangkok s northern and western flood plains that were inundated for several months last year. Many industry pundits have even predicted that Bangkokians will now prefer buying units in highrise condominiums. However, history may still be on the side of single-family homes as the preferred mode of living for most Thais. 45 Asia-Pacific Housing Journal

3 Property Perfect s designs rethink Soon after the floods began receding in early December, Property Perfect Plc promoted a housing design that incorporated three additional protective layers from housing estate s base to the house itself. Before commencing construction, the company said that it would initially raise project roads an additional 30 centimeters to ensure more flood protection. The ground floor of the new flood-proof houses will now be 1.1 meters above the new project road, high enough to ensure the house stays dry in a one-meter high flood. Parking areas will also be raised so that automobiles will be relatively safe from floods of up to one meter. In addition, the fences around the entire project will be designed to prevent water from flowing above and below ground. Each project will now also include pumping stations and mobile pumps that operate on electricity or diesel in case of power outages. The company has also implemented design elements that will impede flood waters from damaging the homes. In most cases, in addition to entering from doors and windows, flood waters can also inundate homes through water drains and other such openings. Valves will now be installed in water and drainage pipes to prevent such back flows. Cesspools will be also be redesigned to inhibit back-flows of contaminated and foul-smelling elements. Interior floors will also be redesigned so that electrical switches and sockets will now all be at least 1.2 meters about the floor, while circuit breakers will be moved to stair landings. To prevent underground seepage, concrete panels 50 cm deep will now run along underground beams on all four sides of houses. Asia-Pacific Housing Journal 46

4 Innovative flood mitigation ideas Elevated housing designs Elevated PD House design for 200 sqm raised house Bt3.5 million on 80 sq wah of land Another company, PD House has adapted and modernized the traditional homes built on stilts for it new homes. The living areas begin on the second floor which is more than three meters above ground level. The inhabitants will be able to continue living comfortably even if flood levels reach three meters. The above graphic shows how beautiful modern homes can be built with basic concept. We can all imagine that behind the two cars, is a motor boat that can be quickly launched during the next flood. Amphibious houses Thailand has a long history of amphibious housing designs. At the beginning of the 20th century, many people lived on rafts and other amphibious houses on the Chao Phraya River, in Songkhla and in Phitsanulok. During annual floods they could ride out the storms and live comfortably. However, growing urbanization eliminated him and canal living that often included floating seagardens. Pollution of the water ways was often cited as a reason for banning these floating homes. 47 Asia-Pacific Housing Journal

5 Many modern Thai architects including Chutayaves Sinthuphan are now advocating the construction of amphibious houses that can be built to withstand floods particular in Bangkok s northern and western flood plains. These Amphibious House are designed with prefabricated flotation systems that sit on a trench under the house. According to Chutayaves, the entire system can be hidden so the house looks similar to houses in the surrounding areas. When floods or heavy rain arrive, the depression collects the water and as the water level rises, the depression (trench) is filled and the house becomes buoyant. Asia-Pacific Housing Journal 48

6 Innovative flood mitigation ideas The homes themselves will be built with prefabricated panels with steel framing. Chutayaves said that the construction method allows the house to be much lighter than traditional construction yet remain strong during everyday wear and tear. These amphibious homes are designed for survival during floods. It has built-in backup systems including food storage, rain collection and power-generation systems. The homes are also latticed together in groups of five to ten to form mini-communities in times of flood. Amphibious homes are also regularly constructed in Holland but few are for low and middle income individuals 49 Asia-Pacific Housing Journal