In theory, cinder block and cement block seem like the same thing. After all, they are both precast and have the same rectangular shape. However, making the wrong choice can mean your load-bearing walls stand like sentries for ages or collapse over time, especially in humid areas. So, to understand the difference between the two, we got in touch with Peter Krawchuk, a contractor and carpenter, and founder. New day construction. As Hunker explains specifically, “The main difference is the aggregate used inside the block. Traditional cinder blocks contain coal cinder or ash, which makes them lighter, more porous and generally weaker. What people call cement blocks are concrete masonry units usually made of Portland cement and are much better strengthened. Suitable for moisture exposure and structural loads.”
As a result, cinder blocks fell out of favor after the mid-20th century and were replaced by cement blocks. The latter’s inherent strength and resistance to moisture cannot be ignored, says our expert. Today, the former is largely relegated to DIY projects, while the latter is required for structural integrity in projects, such as building partition walls if your The open floor plan looks overwhelming. But if you find it difficult to differentiate between the two based on their appearance, our expert suggests evaluating a block by its weight. “If you pick up a real cinder block, it feels remarkably light and almost chalky, and you can sometimes see a dark, ash texture in the aggregate. Modern concrete block feels dense and solid in your hand,” he says.
When should you use cinder blocks?
Although no longer widely used in construction projects, cinder blocks have not been completely phased out. Peter Krawchuk said in his exclusive chat with Hunker, “I would only consider cinder blocks for light, non-structural projects where easy handling matters. A short decorative garden wall is a good example – the blocks are easy to lift and stack, and there’s no real weight on them, so their strength is low.” But if you want this wall to double as a secure boundary and keep intruders out, you may want to rethink your choice.
You can also create a raised planter bed, notes our expert. “I’ve found cinder blocks to work well here because the open cores can actually be planted directly, and the light weight makes them easy to rearrange if you change the layout of your garden,” he tells us. However, keep in mind that they cannot withstand the natural elements as well as cement blocks. So, you’ll have to change them more often, especially if you experience humid weather, he warns.
You can too Turn cinder blocks into a stylish backyard barA seasonal bench, portable fire pit, or temporary shelving in your garage or shed, he says. Basically, it’s a good option for projects that you don’t expect to last for decades or don’t have adequate load-bearing capacity. He explains, “They should be avoided for foundations, retaining walls, or anything exposed to frequent freezing, moisture, or heavy loads. Their porous structure makes them less durable than modern concrete blocks — in the Pacific Northwest, where I build, that moisture exposure is constant, so I avoid anything permanent for clients.
When should you use cement or concrete blocks?
Comparing high-performance cement blocks with lightweight cinder blocks, Peter Krawchuk highlights the best use cases for the former in an exclusive conversation with Hunker. “Concrete blocks are a better choice wherever strength and durability are important,” he tells us. “First place are foundations and load-bearing walls. On our home additions and ADU builds, concrete masonry units are standard for stem walls and foundation work because they reliably handle compression loads and meet code requirements that cinder blocks simply won’t.”
Our experts believe that it is also the best material for retaining walls. Sharing his personal experience, he says, “I’ve seen too many failed retaining walls built with the wrong materials – once soil and water pressure are involved, you usually need the right concrete block density and strength, with rebar and grouted cores.” With this in mind, you shouldn’t compromise on quality and choose inferior materials (such as cinder), or you’re making a costly mistake, he warns.
Cement blocks are also a good choice if you prefer Build a concrete block shed A foundation, or other permanent outdoor structure, such as patio or garden steps, or a detached garage foundation, emphasizes the Krawchuk. “Anything that sits on grade and is exposed to the weather year-round should be concrete blocks,” he says. “They conduct moisture better than traditional cinder blocks, which is why concrete masonry units became the standard for structural and below-grade construction.” In other words, it is the best option for structural applications and should never be replaced by cinder blocks if you want a resilient structure that will stand the test of time, especially in humid regions.
