Things You'll Need
Chalk or grease pencil
Cinder blocks, also known as concrete masonry units or foundation block, are an integral part of both small- and large-scale structural projects. The blocks are typically formed from concrete aggregates and low-density cinder ash. Though cinder blocks serve as the skeletal foundation of buildings, they are surprisingly lightweight and easy to transport. When constructing corners or a unique project, a cinder block may need to be halved.
Put on your gloves and safety goggles to protect yourself from flying bits of concrete and dust.
Measure the length of the cinder block and divide by two. This will provide you with the halfway point from one side of the block to the other.
Draw a line at the halfway point using a piece of chalk or grease pencil. Flip the block over and draw an identical line at the halfway point. Use a ruler to make the line as straight as possible.
Place a chisel on the guiding line at one edge of the block and tap it with the hammer. Move across the line, tapping every inch or so, until you reach the edge.
Flip the block over and repeat, chiseling along the line.
Pull the cinder block apart and survey the edges of your two halves. Use your chisel to chip away any especially jagged edges or protruding aggregate.
If your block has not separated after Step 5, continue tapping the length of each guiding line until it splits.
If you want a smooth edge, use masonry sandpaper.
Do not allow children or pets near your work area.
Handle the hammer and chisel with caution. The chisel's edge is sharp and can cause serious personal injury if mishandled.