By Rey Anthony Chiu | 02:47 PM January 02, 2022

When typhoon Odette blew her wrath over northeastern Bohol, gale force winds peeled off house and building roofs, burst open gables and launched entire roof segments: rafters, purlins and all.

Amid the huge swaths of havoc which Odette left in her trails are few houses still standing strong amidst the mayhem.

These houses have a common element: they sport a typical four-sloped or four angled roof system designers would call as the hip roof.

Cuatro aguas.

Compared to its cousin the gable roof, or dos aguas, cuatro aguas have the typical four sloped roof common among Spanish and old Filipino houses.

What is with this type of engineering and architectural roofing marvel that makes it withstand and resist the gale force winds Odette packed?

For house builder Rey Tirol, the frame structure itself is boxed type and more triangulated, the outside form deflects most gale force wind hence it stays put.

And, as to the houses with cuatro aguas roofing, the steeper and more trapezoidal is the roof, the better are its chances of deflecting the winds.

According to architect Ronald Jose Malanog, architecture learners are taught on orienting structures according to the sun’s path and prevailing winds.

Organic architecture uses the sun to light the entire house and planning the house on prevailing winds make one fortify it better for the big ones that come. Like Odette.

If we look back at history, most houses are built with cuatro aguas, maybe because of their experience. They saw that this roofing style is effective considering the Philippines and other tropical countries are prone to inclement weather, Archt Malanog said.

Apart from steep roofs facilitating the draining of rainwater, the roof easilly dries, this should be very effective in playing with the wind during storms and rains.

In Bien Unido for example, houses which sport doble aguas or gable roofs are often left roofless, some tin sheets getting peeled off if the purlins are well secured and the rafters well anchored.

Looking under the typical Boholano houses with cuatro aguas would show a web of hip trusses and web members that make the entire roof frame a stable support for the roof slope even it it is using nipa as roofing material.

Modern day construction however has introduced many designs, and people have used uniqueness and beauty over function and reliable stability as their factor for their roofing options .

For those constructed without considering the force of the winds, entire roof slopes including beams, rafters and purlins are launched into the air, leaving gaping holes and drenching everything under.

But, even if your roofing has a good angle to deflect the wind and it is securely fastened, still a huge factor in the strength and stability is a good and proper design and materials, says another builder Fem M. Pajo.

Most house roofs that were crumpled or were blown away were from substandard tin sheets or under-sized and far spaced purlins.

In architecture, there is a subject that tackles the building orientation with respect to the sun path and the prevailing wind, Architect Malanog added.

Houses built with dos aguas and with its open side facing the wind give the gusts enough resistance to trap the wind until the force can strip roofs from houses.

As soon as you have the building oriented properly, the proper plan, good work and use of standard materials based on the historical records of previous storms and inclement weather comes into factor.

In fact, following what happened with the locally biilt structures with Odette, it could be high time for authorities to review building plans and make more typhoon resilient houses in the future.

That however needs no reinventing. (rach/PIA7/Bohol)

By Bohol Island News

Your reliable source of news and content in the island and the rest of Central Visayas and Mindanao.

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