Looking for popular concrete block sizes? Concrete blocks are a commonly used construction material for close to a century.
Sometimes called a concrete masonry unit (CMU), concrete blocks are typically large and rectangular and made from cast concrete. Cast concrete is a mixture of Portland cement and aggregate.
Aggregate can be sand, gravel, or industrial waste. The term cinder blocks came from the use of cinders as the aggregate material in the creation of the blocks.
Informally, the term concrete block or cinder block is used interchangeably.
Concrete blocks are created in different sizes and structures to suit different purposes.
Common Concrete Block Sizes
The most common of concrete block sizes is the 8 x 8 x 16 inch block. The size is scaled down by 3/8 of an inch to permit mortar joints.
There are larger and smaller sizes of block available. Once you review the list of blocks below and have an idea of the dimensions of a construction project, it is easier to select the sizes needed.
All 8 inch block, which is the standard, are sized down to 7 and 5/8 inches in width for mortar.
The standard CMU of 8 inch block is used in most block construction. The half blocks with corners are used to terminate a block line.
Types of Concrete Blocks
- Use either a single or a double corner block to ensure a smooth finished corner. A concrete block that is called bullnose has one or more rounded exterior corners.
- Jamb joist blocks are for use around doorways to support the jambs that are supports for floors, ceilings and doors.
- Sash units are used to create an opening for casement windows.
- Header blocks, which come in solid and hollow, are for supports that will be placed at the top of any wall.
- Ashlars are cut on all faces that are adjacent to other blocks so very thin mortar joints can be used.
- Bond beams are hollow and made for connecting to other blocks by the use of grout. They are placed on the tops and bottoms of walls to help weight distribution.
- A lintel is a block that is placed horizontally so it spans an opening between two vertical supports.
In many cases, the blocks have knock out (K.O.) sections, that are removed when the blocks are used in the bond beam.
Special blocks, such as the ones listed in the Miscellaneous Concrete Block Sizes section below, are used for special requirements such as chimneys. Depending on the project, there are many different specialized blocks for specific purposes.
In many cases, the best alternative to concrete block is wood frame construction.
Designing a masonry project begins with plans. Before beginning any concrete block construction project, it is important to check the local building codes and requirements.
Localities differ in their building codes and permit regulations. A check of these rules is a good first step in deciding what sizes and materials will be needed for the job.
Standard 8 Inch Concrete Block Sizes
The standard size 8 inch block comes in the following sizes:
8 x 8 x 8 Half
8 x 8 x 16 Hollow
8 x 8 x 16 Sash with Breaker
8 x 8 x 16 Solid
8 x 8 x 16 75% Solid
8 x 8 x 16 Thick Wall 3HR Fire rated
8 x 8 x 16 Single Bullnose
8 x 8 x 16 Double Bullnose End
8 x 4 x 16 Ashlar
8 x 4 x 16 Solid Ashlar
8 x 8 x 16 Bond Beam
8 x 8 x 16 K.O. Bond Beam
8 x 8 x 16 K.O. Beam Lintel Conduit
On the smaller end, solid and hollow concrete blocks come in sizes 2 inch, 3 inch and 4 inch. The smaller concrete block sizes are as follows:
2 x 8 x 16 Solid
3 x 8 x 16 Solid
3 x 8 x 16 Corner
4 x 8 x 16 Hollow
4 x 8 x 8 Half
4 x 8 x 16 Solid
4 x 8 x 12 Starter
4 x 8 x 16 Bullnose
4 x 8 x 16 Double Bullnose End
4 x 4 x 16 Ashlar
4 x 4 x 16 Solid Ashlar
Miscellaneous Concrete Block Sizes:
2-1/4 x 3-5/8 x 7-3/8 Concrete Brick
16 x 8 x 16 Chimney Eye Block
17 x 8 x 17 Chimney Regular
17 x 8 x 21 Chimney Regular
8 x 8 x 24 Labor Saver
8 x 8 x 16 Hollow Header
8 x 8 x 16 Solid Header
Hopefully this information about the different sizes of concrete blocks you can find is helpful in your next construction or home improvement project. Given their versatility there is a good chance you will be using concrete blocks for anything from a bathroom addition to a new patio, deck or even a garden shed.