How to Earthquake-Proof your Homes Philippines

Updated: Apr 6

1.) Recheck lot location

This is one of the most crucial part to make your homes “earthquake-proof”. Most people only see to it that the lot they are eyeing at is not flood-prone or storm-prone. When you can, avoid lot area that is near active or developing fault lines. Well, this advise is no-brainer.

Please avoid it else you’ll have to throw out additional money to reinforce your homes.

I know of some big developer in the country where they deliberately do not inform the public that their area is in near “developing” fault-line. Apparently, one of the requisites to be called as an “active” faultline is for the fault line to have an active seismic activity near the area, but what if it is just a “developing” fault? Would you still invest in the property? I guess not. Seek advice to geodetic engineers on this one.

2.) Hire a Registered Civil Engineer / Architect

Like yeah, you really need one. When you are sick you go to a doctor to heal you, because they are the ones experts to heal you. Same goes with building and construction. We, are the professionals who attended several years in school to gain our knowledge. The only difference is that we already anticipated the diseases that will undergo your house and we plan to resolve it before it becomes sick.

Your location's got a soft soil? Okay, we'll find the most economical depth of foundation for that.

Near a cliff or faultline? Okay, let's see what we can do to find the most prudent structural design for that.

3.) Think twice when you downgrade material for savings

Some materials were chosen by the professional for a reason. During your home construction, I believe there would be times that certain material is not available, thus, you will be tempted to purchase a cheaper alternative. An example is Grade 60 – 16mm diameter reinforcing bars vs. Grade 40 – 16mm diameter reinforcing bars. Of course Grade 40 is cheaper. Opt to buy the required Grade 60 because it is much structurally stronger compared to Grade 40.

Note that columns that uses 16mm needs to use G60 as it is considered to be a main structural member.

4.) Structural over Aesthetic

We all want to have a unique home. But if what you want is to omit the center column to achieve the minimalist look, you better think twice as it would mean you have to make the beam overhead bigger. If the beam is bigger, you would also need to upsize the columns that hold them.

Also, there are reasons why most engineers design homes to be symmetrical. Symmetrical design prove to be more adequate to resist seismic movements or destruction compared to complicated ones. When you want your homes to be earthquake-proof, seek for a symmetrical design. I know there are new ways to achieve both good-looking homes with s definite structural integrity but it would mean additional expenses. Anyway, I’m on it if you can afford it.

5.) Follow What is Planned

Not only would you need a professional for the design of your plan. You also would need to hire one for the actual construction of your homes. But I’ll give you a heads up before your engineers interpret the plan for you. Also, the following are the ones most neglected by foreman for the client to save money.

[ Never forget the vertical and horizontal reinforcing bars for your concrete hollow block walls.]

I know that most foreman would make the vertical spacing wider to save some reinforcing bars. Yes, you can choose this but this would eventually hurt your expenses in the long run. 0.40 meter is the minimum required spacing of vertical bars as adapted in the Philippines. The minimum reinforcing diameter for masonry wall is 10mm (please use 10mm diameter bars minimum, not 8mm, period).

[ External walls should be 6-inch concrete hollow block with well compacted mortar in all cells and joints. The advised mixture is 1:4 cement per washed river sand. ]

In addition, for every construction, it is discouraged to use sand and gravel taken from beaches and shorelines as studies show that it introduces rust to the reinforcing bars making it thinner overtime.

[ Do not exceed one-inch thickness of plastering works. It is globally accepted that the maximum thickness for plastering is 6mm for ceiling and 12-20mm for walls. ]

The picture below is an example of too thick plastering. This is hazardous as it may peel during or after an earthquake. If you really need to thicken plastering, better reinforced this with a welded mesh.

It is not only the walls that needs to be fully reinforced. But also, the beams, foundation and the columns. Please take note that beams, columns and the foundation are the three important structural members of your house. For those who have truly no idea what are these members.

The picture on the left are the basic structural members and the photo on the right is the reinforcing bars of a typical wall footing in the Philippines.

Foundation is the part where you do not see as it is embedded thru the earth. The picture on the right above is a wall footing which is the foundation for concrete hollow block walls. This normally has foundation depth of 0.6m to 0.8m.

Most plans as I have seen have column foundation with depth 1.0mm minimum for the two-story houses. But of course, the depth depends on the strength of your soil. (Ask you engineers on this one, he knows better).

I may not point out all of the tips on earth-proofing your homes as it would take me my entire 5-year course to explain. The only advise I would let is hire a professional for the designing and have a professional during the actual construction. That is the only direct way to ensure that you “earthquake-proof” your homes.

Oh, the last thing, one can never really fully “earthquake-proof” as we are yet to know the strongest earthquake ever. Just be wise enough to get a licensed professional.

Let me know what are your thoughts, concerns and questions. I’ll answer them when I can!

©2019 by untaught engineer.