Flood-proofing our homes

Every year, as I get older, I often ponder life and the experiences that have helped shape me into who I am today.

Indeed, I am different from the person I was 25 years ago, and in the same vein, so is the world. Yet, even with all these changes, certain things still stagnated and never evolved. I find myself ruminating about the Philippines and realizing that, after all this time, we have still been unable to address the issue of flooding in our cities.

By now, every Filipino has shared a kindred experience with typhoons. We have waded in the water, whether in a car or on foot. We find ourselves stranded in one place, unable to travel thanks to flooding. We have heard countless times that Filipinos are resilient, and we will survive this.

Truthfully, over these past few decades, our government could have done more to establish new standards to address this prevailing issue. Let me illustrate three simple yet effective ways to floodproof our future and existing homes.

The first is common sense, but it bears repeating: stop designing buildings below the design flood elevation (DFE) or the expected water level during a flood. The habitable spaces of our homes should be above the DFE. The problem is that we do not have an open-source flood-level database in the Philippines, which starkly contrasts with the United States, which has accurate maps indicating the DFEs for numerous counties nationwide. This database is important because our country has a fascinating geography that varies the flood elevation levels depending on where you live. Knowing the DFE would allow architects to fully design a house without a typhoon completely submerging the first floor. Additionally, this would prevent local building code departments from approving projects that do not conform to the DFE standard.

Now, what happens to the space below the DFE? Is that space completely off-limits? The answer is no; we can use these spaces to introduce breakaway walls. A breakaway wall is a particular type of structure carefully designed to fail safely during a flood. These walls would break apart independently of a home’s main structure. Breakaway walls are the second way to flood-proof our homes, as they allow water to flow through the bottommost portion of our home while leaving the upper floors intact. This, in turn, protects our house’s elevated living quarters and foundation walls. We can still utilize spaces underneath the DFE; however, these should be relegated to unoccupiable spaces such as parking garages, storage and building circulation or access. Our utility spaces must also clear the DFE height to prevent costly HVAC and electrical equipment damage.

Now, for existing homes, we can bolster their flood resistance through dry flood-proofing, which involves sealing the exterior of a building from water infiltration. One method for achieving this is to install waterproofing membranes on exterior walls, foundations and slabs. Another uses waterproof sealants to seal any open structural joints and window and door openings. These two are just small samples of ways to add to our current homes to be more flood-proof.

Because of climate change, flooding in the Philippines will continue to happen. While the government has no clear path to address this issue, it does not mean we don’t have ways to flood-proof homes ourselves.