Around the edge of the slab, the concrete forms a beam that is perhaps 2 feet deep. The rest of the slab is 6 inches thick. Embedded in the concrete is 6-inch by 6-inch wire mesh (shown by the dotted line in the slab) and steel reinforcing bars (shown by the white circles at the bottom of the beams). These innovative and practical engineering technology are now available and appropriate to homes built in warm climates and calamity-prone areas like the Bicol region. For comments and inquiry please email hamodyong@hotmail.com The foundation of a house will determine the big difference in the damages caused by typhoons and other natural calamities like floods, earthquakes, etc. An engineer showing the thickness and strength of the slab foundation



On the average, the Philippines is visited by 19 tropical cyclones every year. According to Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA, a weather disturbance becomes a tropical depression when wind velocity reaches 64 kilometers per hour whereas a wind velocity over 120 km/h is classified as a typhoon building up into a super typhoon when maximum winds is greater than 185 km/h. Almost all of these are accompanied by rain, at times, very strong rain that result to floods and landslides

        In would be noted that PAGASA listed Bicol as one of the regions most frequently hit by typhoons resulting in enormous damage to properties and massive loss of lives.

        With the onset of the rainy and typhoon season, are we safe and secure in our homes?

        Typhoon-resistant dwellings

        How then do we design typhoon-resistant houses?

        As a general rule, the foundation of the house will determine the big difference in the damages caused by typhoons, and other natural calamities like floods, and earthquake, etc.. If a foundation is not good, the rest of the house will have problems. Choosing a foundation type should be made while keeping in mind the cost, soil composition, and weather conditions of the area.

        The Holy Scriptures give us an appropriate advice, “ He is like a man building a house, who dug deep and laid a foundation on the rock; and when a flood occurred, the torrent burst against that house and could not shake it, because it had been well-built.” Luke 6:48

        In low-lying areas, houses may be built on concrete blocks or wood one or two feet above the ground so that flood waters can flow underneath. Houses supported by four reinforced concrete columns about 10 feet apart can withstand water or wind force more than a traditional house made of concrete hollow blocks.

        The House’s Foundation

        A house needs a foundation to shoulder its considerable weight, provide a flat and level base where the house is constructed, and one that separates wood-based materials from contacting with the ground. Such contact would otherwise cause the house to rot, and allow termite infestation.

        The foundation may be made of stone, brick, preservative-treated lumber, concrete block or poured concrete. By far the most common material for foundations is the concrete. There are three types of conventional concrete foundations: poured concrete, concrete block and post-and-pier. The size and acceptable types are regulated by the national building code and closely supervised by city or municipal engineer’s offices. A poured-concrete foundation may be either a raised, perimeter foundation, a flat slab or a combination of the two.

        Most houses have a raised, perimeter foundation that supports floors and load-bearing walls. Some are built on a flat, concrete slab that provides both a base for the structure and the bottom floor of the house. The bottom part of a foundation is called a footing (or footer). The footing is generally wider than the foundation wall. The footing distributes the house’s weight to prevent future settling or movement.

        The purpose of a foundation is to provide stable support for the structure, and to anchor that structure to resist the force of winds, including uplift. Because cost is a major element of concern to most homeowners, economy is essential both in site preparation and in the construction of foundation.

        The traditional perimeter wall foundation is a common type of foundation for homes throughout the Philippines. It generally consists of a wall footing of cast-in-place concrete containing some steel reinforcement. The purpose for the footing is to provide uniform support for the perimeter walls. Interior posts or columns are placed on individual footings to support interior beams. A conventional perimeter foundation has a poured concrete wall supported by a poured concrete footing. Both are strengthened by steel reinforcing rods (sometimes called rebar). This type of foundation is used in connection with both raised floors and slabs.

        Although the perimeter wall foundation is economical both in materials and in the cost of construction, yet it is poorly suited to unstable ground. There is a great potential for damage from uneven movement in the subsoil. Fractures may appear in walls after only minimal distortion, or differential movement. It lacks strength and stiffness and does not allow for flexible or adjustable connections with the house structure.

        On the other hand, a stiffened slab is constructed in a fashion similar to a conventional concrete slab-on-grade building support; however, the recommended thicknesses for stiffened slabs generally exceed those of conventional slabs; thickness is further increased around the edges, and additional ribs of concrete are used to reinforce the slab’s midsection. The entire structure is heavily reinforced with steel.

        The rationale for stiffened slabs is that design must allow the foundation to resist the resulting stresses without excessive deformation. It must be noted that the current state of the art, and the successful local practice of the local developer ENJOY REALTY has been established, including design innovations that economize on the use of reinforcing steel and concrete.

        Appropriate housing technology

        Technologies related to reducing the cost of foundations have been available for many years, but have not yet found widespread acceptance. Building codes have only recently acknowledged alternatives to the conventional foundation systems. In most cases, local homeowners are not aware while home builders and real estate developers have not been receptive to these alternatives.

        Slab foundation is a flat concrete pad poured directly on the ground. However, the site preparation is tedious since the topsoil and unsuitable loose materials are first removed and changed with Item 201 graded soil composed of 1/3 soil, 1/3 sand, and 1/3 gravel compacted layer by layer until it has achieved the soil bearing capacity. This solid foundation which has a thickness of 6 inches is often referred to as a “floating slab” -- it “floats” on the soil, with the deeper concrete around the edge holding it in place. The solid concrete wall (buhos) is done simultaneously with roofing of the slab, thus, making it stronger and structurally stable. Cast as a single unit, it resulted into a monolithic slab, where footings, foundation and slab are a single, integral unit.