Concrete Block Types or Concrete Masonry Units Used in Construction

Concrete Block Types


There are various types of concrete block used in construction such as houses, buildings, etc.

They are manufactured in any required shape and size and may also be concrete or hollow blocks.

The distinctive dimensions of concrete blocks are 39 cm x 19 cm x 30 cm or 20 cm or 10 cm or 2 inches, 4 inches, 6 inches, 8 inch, 10 inches and 12 inches.

Concrete blocks are prepared with Cement, aggregate, water, the cement-aggregate ratio in concrete blocks is 1: 6 (60% high-quality aggregate and 40% coarse aggregate)

Their minimum strength is about 3N / mm2. ASTM C- 90-91 specifies the compressive strength requirements of concrete masonry units.

Types of concrete block or concrete masonry units:

Concrete blocks are mainly classified into 5 types, based on construction, form, shape and are as follows:

Solid Concrete Block

Solid Concrete Block:

Solid Concrete blocks are usually used for the constructed from heavy and dense aggregates.


They are extremely strong and provides good stability for the structures & they are preferred for large work of masonry like load-bearing walls.

They are available in larger sizes than bricks, therefore concrete masonry takes less time to produce than the brick masonry.


  • Compression Strength: 5 – 8 MPa.
  • It can be manufactured on-site for economical manufacturing.
  • Lowest water absorption.


  • High density (2100 to 2200 kg / co).
  • High dead load on the structure.
  • Dimension variations are observed.
  • Installation is labour intensive and time-consuming.

Cost of material: Rs. 45 / sq.ft (for 150 mm wall)

Available in specific sizes: 390 * 190 * 190 mm, 390 * 190 * 140 mm, 390 * 190 * 90 mm,

Best Use: Low Growth Construction.

Hollow Concrete Block

Hollow Concrete Block:

In hollow concrete blocks, the void space is more than 25% of the gross space & a solid area of hollow bricks must be more than 50%.

The hollow part can be divided into numerous elements depending on our requirement, made of lightweight aggregates & easy to install.


  • Compressive strength: 5 – 8 MPa.
  • Density: 1250 to 1400 kg / co.
  • Reduces dead load on the structure.
  • Built on-site for economical manufacturing.


  • Installation of services requires concrete filling post things, wastage.

Material Cost: Rs. 40 / Sq. (For 150 mm wall)

Available in specific sizes: 390 * 190 * 190 mm, 390 * 190 * 140 mm, 390 * 190 * 90 mm.

Best Use: Low Growth Construction

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Types of hollow concrete block:

Concrete Stretcher Block:

Concrete stretcher blocks are used to stick the corners in masonry. Concrete hollow blocks are used widely in the construction of stretcher blocks.

They are situated parallel to the face of the wall.

Concrete Corner Block:

Corner blocks are used at the ends of masonry, this may be window or door openings.

They are arranged in such a way that the end of their plane is visible outward and the other end is closed with a stretcher block.

Concrete Column Block:

Pillar blocks are often referred to as double corner blocks when two ends of the corner are visible.

Jamb Concrete Block:

Jamb blocks are used in the opening of a large window, attached to a stretcher and corner block.

For the provision of double-hung windows, jamb blocks are very helpful to provide space for external members of the window.

Split concrete block:

Split concrete blocks are commonly used to assemble partition walls.

The width of partition blocks is larger than its width.

The hollow parts are divided into 2-3 elements. Also, read Concrete Block types FAQ.

Lintel blocks:

They are used for the provision of beam or lintel beam.

They are usually provided on the top portion of the doors and windows, to bear the above load.

Concrete lintel blocks have a deep groove with the shape of the block. After placing the blocks, the drain is filled with the concrete reinforcement.

Frog Brick Concrete Block:

Frog brick blocks have a frog-like head with headers and stretchers.

This helps in applying mortar to the frog blocks and developing a strong bond with the top laying blocks.

Bullnose blocks are like corner blocks. Their duties are moreover similar when we most need round bricks within the corner.

Light Aerated Concrete Block

Light Aerated Concrete Block:

Concrete blocks are constructed from concrete (i.e. Portland cement, aggregates, for high-density blocks sometimes sand and high-quality gravel is used).

Light blocks are produced using the autoclaved aerated concrete.


  • Lightweight (density = 600 – 700 kg/co), much lighter, reduces the dead load on construction.
  • Reinforcement consumption can be optimized.
  • Ease of chisel for services (electrical and plumbing).
  • Less time-consuming.
  • Higher accuracy amplitude.
  • Better thermal and acoustic properties.


  • Strength: 3 – 5 MPa.
  • It can be handled properly for a low breakdown.
  • It cannot be manufactured on-site.
  • The unit value is excessive.

Material cost: Rs. 50 / sq ft (for 150 mm wall)

Available in specific sizes: 600 * 200 * 200mm, 600 * 200 * 150mm, 600 * 200 * 100mm

Best Use: High Rise Construction. Also, read Concrete Block types Conclusion.


Cellular Lightweight Concrete Block:

This is a light-weight construction material that combines good mechanical strength with low thermal conductivity and ease of working.

It is a low-density Portland cement with a large variety of small air bubbles.


  • Lightweight (density = 550 to 650 kg / cu).
  • Reduces dead load on construction – reinforcement consumption-optimized).
  • Dimension accuracy is increased.
  • Much less labour-intensive and less.
  • Built on-site for high thermal and acoustic properties.
  • Economical production.
  • Reduction in plaster consumption is time-consuming.


  • In early-stage technology, the compressive strength is 3 – 4 MPa lower than the various options,
  • Less breakdown requires high-quality management to properly control manufacturing.

Cost of material: Rs. 45 / sq ft (for 150 mm wall)

Available in specific sizes: 600 * 200 * 200mm 600 * 200 * 150mm, 600 * 200 * 100mm

Best Use: High Rise Construction.

Fly Ash Brick

Fly Ash Brick:

Fly ash bricks are lighter in weight and less expensive than clay bricks.

Fly ash bricks are made of waste materials that come from combustion of coal in thermal power plants.


  • Compression strength 3.5 – 5 MPa.
  • Ease of installation of services (electrical and plumbing) is less labour-intensive and less time-consuming.


  • Higher density (2100 to 2200 kg/co) amplitude variations were observed,
  • Increasing the consumption of plaster.

Material cost: Rs 25 / sq.ft (For 150 mm wall)

Available in specific sizes: 230 * 150 * 80mm, 230 * 150 * 100mm, 230 * 100 * 100mm

Best Use: Low and mid-rise construction.

CMU Block Sizes:

Concrete block masonry is also known as a concrete masonry unit (CMU) and it has many benefits over the brick and stone masonry & list of the standard size of CMUs  as follows:

4-inch CMU:

Actual Size 3 5/8 x 7 5/8 x 7 5/8 Nominal Size 4 x 8 x 8

Actual Size 3 5/8 x 7 5/8 x 15 5/8 Nominal Size 4 x 8 x 16

6-inch CMU:

Actual Size 5 5/8 x 7 5/8 x 7 5/8 Nominal Size 6 x 8 x 8

Actual Size 5 5/8 x 7 5/8 x 15 5/8 Nominal Size 6 x 8 x 16

8-inch CMU:

Actual Size 7 5/8 x 7 5/8 x 7 5/8 Nominal Size 8 x 8 x 8

Actual Size 7 5/8 x 7 5/8 x 15 5/8 Nominal Size 8 x 8 x 16

10-inch CMU:

Actual Size 9 5/8 x 7 5/8 x 7 5/8 Nominal Size 10 x 8 x 8

Actual Size 9 5/8 x 7 5/8 x 15 5/8 Nominal Size 10 x 8 x 16

12-inch CMU:

Actual Size 11 5/8 x 7 5/8 x 7 5/8 Nominal Size 12 x 8 x 8

Actual size 11 5/8 x 7 5/8 x 15 5/8 Nominal Size 12 x 8 x 16

Also, read 1. Types of Valves 2. Types of Buildings 3. Types of Pumps

Frequently Asked Questions:

What size is a concrete block?

Two standard sizes (length x height) are 440 x 215 mm and 390 x 190 mm.

Which block is best for construction?

Traditional clay brick is always the best.

Which one is better bricks or concrete blocks?

Both concrete block and brick masonry are strong, fire resistant, insect-proof construction materials.

What are the big concrete blocks called?

It is a standard-sized rectangular block used in building construction, available in different sizes.


Different types of concrete block are designed and manufactured for different purposes, they are highly versatile building materials.

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