Sometimes called cement blocks, breeze blocks are used in a variety of applications, including basement walls and backyard retaining walls. Although breeze blocks are often referred to as concrete blocks, the terminology is incorrect. Lighter than pure-concrete blocks, breeze blocks are composed of coal ashes--cinders--and concrete.
Available in a wide range of sizes from two inches to 12 inches, solid breeze blocks come in both long and narrow and large and squat. Solid breeze blocks can be used to create a whole wall or as capping blocks for hollow breeze blocks, and they often have a groove in one edge of the block that can be filled, or used to run wire.
The type of breeze block most people are familiar with, hollow breeze blocks have big holes in the centre. The number of holes varies from one to three depending on what size the breeze block is and what the block is typically used for. Hollow breeze blocks can be closed- or open-ended and may have curved, or bullnose, corners.
Open-ended breeze blocks have ends that curve inside, instead of squaring off or having bullnose corners. Typically larger and longer, open-ended breeze blocks are often used for larger construction projects such as wall building, and can have shallow or deep open ends.
If you're building a house or working on a special construction project, a number of speciality breeze blocks are available. Beam blocks, which look like either a large W or U, are used for placing and bonding beams into or onto a breeze block wall. If your project includes an angle other than 90 degrees, you can use an angle breeze block to complete the project, or if your plan is to build a small chimney, create one out of chimney blocks, square speciality blocks with a hollow interior.