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  • Writer's pictureBonnie

CMU Foundation Piers

I commonly see concrete masonry units (CMU) used as foundation piers when I'm inspecting a crawlspace. While this can be an acceptable material to support the load of your home, there is an important discussion to have about how the blocks are placed.

The CMU blocks usually have two open cells, and these openings are the weakest areas on the block. In order to protect the block from cracking or breaking at these vulnerable spots, professional installers orient the block where the cells are up and down. When the openings are like cups collecting water, the block has the best resistance and can support vertical loads (weight on top of the block) more effectively.

<-- This is the correct way to place a CMU to maximize its resistance.

The following photos show less desirable ways to place CMUs for vertical loads.

Notice also where the wood beam above the CMU is bearing its weight. Is it centered on the block? Is there isolated pressure directly over the cell opening? This may be a smaller piece of wood that rests on top of the cell opening. If you see this type of work in your crawlspace, you may consider getting a free quote from a local foundation repair company.

Need a home inspection in Little Rock or the surrounding Central Arkansas area? Call or text Honeybee at 501-351-9380.

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