Nowadays the builders tend to prefer poured concrete foundations than foundations made of concrete blocks. Poured concrete is becoming more popular for a number of reasons. Wall forms that are quick to set up and taken down as well as concrete trucks that are able to travel almost everywhere as well as modern pumps and admixtures that create "impossible pours" almost routine.

In spite of the benefits mentioned above, concrete block can be used as a viable foundation material. If the foundation is small -for a home addition, for instance- a builder could save money by laying a block foundation instead of subcontracting the work out to an expert foundation contractor. In the same way foundations for crawl spaces can be quickly and economically constructed using blocks of concrete. If you are a DIYer with masonry skills the block material offers the chance to build the foundation one block at each step.

Before getting any deeper into this "heavy" topic it's important to understand the basics of terminology. In the construction industry concrete blocks are known as "CMUs," short for concrete masonry units. In addition to the standard 16x8x8 in. concrete block stocking most home centers, the array of CMU sizes, shapes , and surface finishes is truly amazing. Most of this selection is intended for commercial construction.

Concrete blocks are made using the same components found in concrete walls, which are gravel (called aggregate) and sand Portland cement and water. Blocks that are light weight can be referred to as"cinder blocks" because fly ash (cinders) which is a byproduct of industrial combustion can be used to substitute heavier ingredients like sand and aggregate. The hollow cores in most CMUs allow the block to be cheaper and easier to handle. They can also be filled with cement sand or foam insulation to increase the durability, thermal mass or insulation value.

Contrary to popular belief the concrete block foundation isn't inherently inferior to a concrete foundation, providing that it's properly constructed. Both kinds Phoenix of masonry require steel reinforcement, and they must be placed on a sturdy firm, solid footing. A good drainage system and damp proofing are crucial. When expansive soils and other external forces cause damage to the concrete block foundation cracks are typically seen in the mortar joints which divide the blocks.