Block Foundation Vs. Formed

Concrete Block Foundation

• Block foundations are constructed from large concrete blocks resting on concrete footings and secured together with mortar. These blocks are laid in an overlapping pattern similar to that used when laying bricks or other masonry blocks. Concrete foundation blocks are hollow, with voids that can accommodate reinforcing bars and be filled with poured concrete once the blocks have been laid.

Poured Concrete Foundation

• Poured concrete foundations are constructed from concrete that is poured on site into forms that have been positioned to delineate the foundation walls. Unlike block foundations, poured foundations consist of a single mass of concrete without seams that is usually reinforced with metal bars that are positioned in the forms before the concrete is poured. As with block foundations, the walls of a poured foundation rest on footers that support and spread the weight of the foundation walls.

Block Foundation Advantages and Disadvantages

• Because they don't require the construction of complicated forms, block foundations can be laid by a homeowner with some masonry experience. When properly reinforced and filled, block foundations are strong, and their thickness gives them excellent insulating ability. However, if not filled and reinforced adequately, block foundations are relatively weak, and their seams make them more prone to leakage than seamless poured concrete walls. Proper drainage, both inside the structure and in the surrounding soil is crucial to maintaining the integrity of block foundations.

Poured Foundation Advantages

• Although forms must be assembled and taken down during the construction of poured foundations, these processes are relatively quick, and laying a poured foundation can be faster than building a block foundation. Because the forms can be built as needed, the design of poured foundation is more flexible than foundations constructed from blocks of standard sizes. The seamless construction of poured concrete walls makes them less likely to leak than block walls. The principal disadvantage of a poured foundation is that it requires specialized skills and equipment generally not available to a homeowner who wants to do the job himself.