all this BS about hallow blocks is crap, i know of houses over one hundred years old still standing, and all this about the cement to sand ratio if you put rebar every 3 feet horizontal , and vertical and filled with cement it is only a form, after the cement dries you can chip the block off and it is solid concrete, if you want to waist money i guarantee there will be someone to take it, all of these arm chair engineers are just that, build the dam house and get on with your life, i have never heard of a cement block house falling down her in Davao, and we have earth quakes all the time the post and beam will work