Flood-proofing lessons for every home

According to a 2012 Malaysian Meteorological Department paper, global warming will result in increased precipitation and flooding in Malaysia and other parts of Asia. Homeowners, developers and governmental bodies need to take steps to reduce or eliminate the damage caused by flooding.

Depending on where the property development is located, the existing structure of the house and the severity of the flooding, here are four techniques that could effectively help flood-proof residential developments.

1. Elevating the home

After flood waters receded in Kelantan, Prime Minister Datuk Najob Razak visited Manek Urai to launch a home building project which involved the construction of 138 houses standing on stilts as high as 2.4m for the people who’d lost their homes in the recent floods. Instead of building conventional homes, up to 3000 elevated ‘stilt’ homes are slated to be built for Kelantan flood victims.

For developers building in a flood-prone area, elevation is the most effective way to flood-proof properties. Though this is commonly thought of to be a costly option, using sustainable materials such as bamboo can greatly decrease the cost of building elevated homes in lower-income parts of Southeast Asia such as Vietnam.

2. Dry flood-proofing

Another way to flood-proof homes is to make sure that effective methods of sealing the home are employed. Ways to do this include painting the exterior walls with a waterproof compound, sealing the walls with plastic sheeting or another impermeable membrane, or installing a waterproof shield around the exterior home.

This method is better for homes in locations that are likely to experience low to mid level flooding, as massive flood water levels (above a metre in height) with too much pressure against the exterior walls can cause the structure in a home to be compromised.

3. Wet flood-proofing

Although it is highly likely that most homes will not be inhabitable during a flood, wet flood-proofing might be the most practical way to reduce the time it takes to clean up properties post-flooding. Allowing the water to flow through a flood-ridden home will minimise outside pressure and possibly save it from collapsing.

In order to wet flood-proof a home, choose waterproof or water resistant flooring. Plan for all electrical outlets to sit well above the high-water mark and make provisions to elevate furnishings and appliances in case of flooding. Installing foundation vents will allow water to flow through the home rather than staying trapped inside during flooding.

4. Sandbagging

When placed in appropriate locations around the home, sandbagging (placing large bags of sand around the exterior of a property) can reduce the impact of flooding. Although this does not stop water flow completely, it can reduce the amount of water entering a home during floods.

As a method of dealing with emergency flooding, sandbagging is considered inexpensive as sandbags can be purchased easily from hardware or landscaping stores. However, proper flood-proofing around the home using dry or wet flood-proofing methods should also be employed for more effective protection.

Other flood-proofing lessons

Bibi Zarina Che Omar, Deputy Director of the Malaysia Drainage and Irrigation Department recommended flood-proofing new homes as the best way to protect them from damage telling attendees at a 2014 Flood Disaster National Conference in Kuala Lumpur that this “method can be adopted as we can no longer afford to widen and deepen rivers”.

Other, more traditional flood mitigation strategies are available as well. For example, Bibi Zarina mentioned the possibility of “focusing on rural areas such as the Sungai Batang Kali area which could be used as a water catchment area, due to its relative lack of development.”

Bibi Zarina also went on to recommend following the example of the Netherlands and Germany in their flood-proofing methods. As much of the Netherlands lies below sea level. Some innovative ways Rotterdam handles floodwater include:

• A water plaza that is a public plaza in the dry season and a water catchment when floods occur.
• A floating pavilion.
• Green roofs that absorb water.

Knowing what to do in advance will also enable homeowners to be better prepared and avoid catastrophe in future occurences of flooding. As parts of Southeast Asia continues to experience flooding, implementing the correct planning and flood-proofing methods will allow coastal land to be properly utilised for future developments.

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