Mamposteria foundations

The rebar cages embedded into the footings are called "castillos". They are placed every 2 (6ft) to 3(9ft) meters vertically and also horizontally. This is done to break down the walls into smaller panels making it stronger. Some are field made of larger diameter rebar and some are bought pre welded and usually are a smaller diameter wire. They are concealed into the finished wall and you really don't know where they are. A pre made castillo costs around MX$90(US$7) and it is 6 meters (20 ft) long. The ones made on site will depend on the size of rebar used.

This is a mamposteria wall in the making. The one shown in the picture will serve as a retaining wall since it will have compacted backfill on one side. I was reluctant to use this type of wall in my house at first. I have always worked with poured in place concrete and I feel it is a more monolithic construction. But after seeing the many structures in Mérida Centro, some which are hundreds of years old, and are still standing I reconsidered. A few factors to consider when using this type of construction are; the expertise of the crew, using stone which comes from your own site excavation and of course the more expensive cost of ready mix concrete and formwork.

The stone harvested from excavating footings and other such as septic, cistern and the pool is recycled into the foundation. Some builders will have you believe that they have to purchase it, but in fact most of it is found onsite.

This is a great picture to illustrate a couple of things. It is from the side wall of the pool excavation. I have encircled in white a portion that clearly shows the topsoil layer and the bedrock. Once you dig about half a meter (20 inches) you find hard rock, and as you can see in the picture it is massive. This is why a mamposteria foundation works so well here and nowhere else which does not have that rock. The structure is basically sitting on a big stone which serves as a firm base for your foundations. This is pretty much typical everywhere in Yucatan except of course the coast where if you dig deep enough in the sand you find the same rock. This also explains the lack of storm sewers in Mérida streets. Could you imagine breaking that rock throughout the city to lay sewer pipes?