Seeing large areas of the Visayas and Mindanao, including the tourism meccas of Siargao and Bohol, reduced to wasteland by Super Typhoon Odette, there is spirited discussion on structural and construction engineering interventions that can be done to make houses and other buildings in our country more typhoon-resistant.
Two presidential aspirants, Vice President Leni Robredo and Sen. Manny Pacquiao are pushing for a shift to domed roofs in typhoon-prone areas, or monolithic domed buildings.
There are also renewed suggestions to begin shifting to underground transmission and distribution lines, as countries such as Germany and the Netherlands are doing.
Based on long-running debates that usually intensify during hurricane, typhoon or tropical cyclone season, however, experts say there are no straightforward pluses for the two measures.
The theory is that a dome roof has less drag and allows the wind to blow around it. Others point out though that without sufficient roof fortification, a powerful storm surge can still blow away an entire dome.
What is needed, they say, is to firmly anchor a roof of whatever shape to the foundation through the walls using devices such as hurricane ties.
Monolithic domes and round homes may be more wind-resistant, but again, with flimsy materials and poor construction engineering, these will prove no match for a Yolanda or Odette-type howler.
Domed dwellings can be pretty; proponents probably have in mind the picturesque blue and white structures on the Greek island of Santorini in the Aegean Sea.
That traditional architecture, however, uses durable stone and volcanic rock.
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Residents in our coastal areas typically prefer to build their homes with durability and permanence not priorities. This is either because they have no choice; they usually jerry-build their own homes using construction materials they gather from nearby forests or coconut trees, plus it’s difficult to build using stones. Or it can be for practical reasons: inexpensive building materials mean less loss in case the structure is destroyed in a typhoon.
The government may have to subsidize the construction of sturdier, more permanent housing for these communities whose livelihoods normally revolve around fishing.
A compromise could be the use of stone for the walls of the house, and lighter material for the roof. An example is the typical heritage Ivatan house in Batanes, which lies along the path of powerful tropical cyclones. The walls are made of stone up to a meter thick while the roof is made of thatched cogon and is steeply slanted.
The slanted roof is said to be more wind-resistant than flat roofs, but several building experts say the opposite is true, since wind passes straight over a flat surface.
Rain and snow run off faster on a sloped roof. But the experts also say that depending on the material used and construction engineering, a flat roof can be even sturdier than a sloped one against rain and snow. A slanted roof, however, is generally more visually appealing than the flat roof we commonly see on modern buildings.
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Visual appeal is also one of the pluses of burying power and telecommunication cables, as suggested by those who think “undergrounding” would minimize vulnerability to typhoon damage.
Even wealthy countries such as the United States, however, have not completely eliminated overhead power lines, even if these are toppled regularly by hurricanes that can be as powerful as Yolanda and Odette.
An article in September 2017 estimated the cost of undergrounding in the US at $1 million per mile (1.6 kilometers). The article noted that burying power distribution and transmission lines can take years to complete, and it could mean an increase in power rates by up to 125 percent. Routine maintenance and emergency repairs can also be more difficult to undertake.
Tycoon Manuel V. Pangilinan, whose business group has a controlling stake in Manila Electric Co., says that Meralco can shift to underground lines, even if this calls for substantial investments. He told us last week on One News’ “The Chiefs” that such a shift would depend on the regulator.
MVP also noted that both underground power lines and ground-level electric posts can be damaged or destroyed in an earthquake, especially the “big one” that seismologists have been warning about in Metro Manila and neighboring provinces.
Some experts argue that undergrounding transmission lines would simply shift typhoon risk in areas prone to corrosive storm surges and torrential flooding.
While this debate is ongoing, MVP said power posts could instead be more securely anchored to their foundations, with steel rather than wood poles used.
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Seeing the devastation from Odette, there are renewed calls for the proper enforcement of easement rules in coastal areas.
This was done in Boracay, but we still have thousands of other islands where coastal communities see tropical cyclones and storm surges as normal livelihood risks.
They might go along with efforts to relocate to safer areas. Unless they are given alternative livelihoods and decent shelters at the relocation sites, however, they are certain to return to the coastal areas.
With the country buried in trillion-peso debt for the pandemic response, I don’t think the government can afford to invest anytime soon in providing Santorini-type or even Ivatan-inspired dwellings to storm-vulnerable communities.
One suggestion is to assist vulnerable residents in building houses made of laminated logs, which are said to be more wind-resistant. Built properly, a log house reportedly can survive a Category 5 hurricane. But the log walls must be securely anchored to rock and the structure must be fortified with devices such as hurricane straps.
Reforms are now being eyed in building standards, to include requirements for the use of interventions such as hurricane shutters, shatterproof glass and reinforced concrete in high-risk areas – mostly communities that face the Pacific Ocean where the tropical cyclones emanate.
Building for resilience is possible, but all the proposals being put forward will take years and sustained interest to carry out, and will require considerable financial investment.
But if we want to protect the next generations if not ourselves, do we have much choice? Perhaps the increasing number of killer typhoons will help people decide.