18th Nov 2022 -

A sturdy building material used throughout the construction industry, concrete blocks offer strength and versatility, suitable for use within a huge range of building projects. In this guide from Building Materials Nationwide, we’ll cover the essentials of concrete blocks, their benefits and drawbacks, their costs, and the different types on sale within the UK. 

We’ll also take a look at some of the building projects where concrete blocks can be used, and the common sizes they’re sold in.

What Are Concrete Blocks?

Concrete is a building material that has been used for millennia, comprised of cement, a mixture of fine and coarse aggregates, and water. In contemporary concrete production other materials, called admixtures, can also be added to give it special characteristics. Concrete has been used in buildings as far back as ancient Egypt, Rome, and Greece, with architectural wonders like the Pantheon in Rome still standing today. In the modern world, concrete is used within almost all skyscrapers, and within a wide range of smaller buildings and construction projects.

Concrete blocks, sometimes called Concrete Masonry Units (CMUs), are standardised dried concrete blocks that can be used within construction much like clay bricks, with mortar bonds between each join. The first concrete blocks were manufactured in the 1850s, and today there is a wide range of products available, with both dense and lightweight options, alongside hollow blocks. 

Contemporary concrete block production is fully automated, with precise mixtures of cement and aggregate shaped into moulds and cured within a kiln.

Need Quality Concrete Blocks?

  1. £3.72 £4.46
  2. Low Stock In Some Areas - Contact Us Prior To Ordering

    • Thermal efficient
    • Easy to cut
    £1.87 £2.24
  3. £1.63 £1.96

View All Concrete Blocks

What Are the Benefits of Concrete Blocks?

Concrete blocks have become a popular choice for a wide range of buildings, from commercial to domestic. There are several specific benefits to using Concrete blocks within a construction project:

  • Acoustic Insulation: Concrete blocks offer excellent soundproofing, giving benefits within both a house and a commercial property. This can help to limit loud noises such as traffic from passing into the interior and reduce noise pollution moving within a building.
  • Thermal Insulation: Using concrete blocks as the external wall of a building will offer solid thermal insulation. This means that heat takes longer to escape from a building, lowering heating costs and energy bills.  Thermal insulation also helps to keep a building cooler in the summer, by keeping the heat from entering.
  • Animal Resistance: Concrete is inedible to insects and burrowing animals like rats. Especially compared to a timber-framed building, the density of concrete will resist damage and keep our pests well.
  • Strong: Concrete Block walls, especially when reinforced, can offer a great level of strength, helpful for those in areas with high levels of wind, and for larger building projects where load-bearing walls are required.

Concrete Blocks vs. Clay Bricks

When looking to build a smaller property within the UK, such as a house, the two main material options for structural work will be concrete blocks or clay bricks. Here are some of the key comparisons between the two:

  • Appearance: Bricks are generally considered to be a more visually pleasing material than concrete blocks, and are installed as-is for buildings like houses. Concrete blocks are seen as less attractive due to their dull colour and flat appearance, and can often be covered by facades or by a thin wall of bricks to improve their appearance. By using different aggregates and additives, there are now more options for the look of concrete blocks than before.
  • Strength: Standard concrete blocks are slightly stronger than bricks offering 3500 PSI (a measurement of resistance per square inch) compared to 3000 PSI for clay bricks. In smaller projects, this difference is likely to have minimal impact, but concrete blocks offer superior strength. Concrete blocks should offer around 100 years of performance, whereas clay bricks can offer up to 500.
  • Weight: Concrete blocks are heavy, with one block weighing around 20kg. Clay bricks are lighter and also smaller, making them easier to transport and install by hand.
  • Cost: Concrete slabs can ultimately be the more cost-effective choice when considering parts and labour. Bricks are generally a little more expensive, and will also require a longer installation time, leading to higher labour costs.

Looking For Clay Bricks?

  1. £548.93 £658.72
  2. £421.96 £506.35
  3. £551.96 £662.35

Browse Facing Bricks

Are Concrete Blocks Water Resistant?

Concrete blocks are porous and will absorb water, which can cause issues with outer walls as water penetrates the blocks, before freezing and expanding during cold weather. This can also cause issues when concrete blocks are in contact with soil. There are sealants available, allowing concrete blocks to be used externally.

Are Concrete Blocks Fire Resistant?

Concrete is inflammable, withstanding extreme temperatures during a fire, and not aiding its spread. While the same is true of clay bricks, other building materials like timber can contribute to a fire, as can various elements of cladding.

Is Concrete Environmentally Friendly?

The concrete industry is responsible for a high level of global CO2 emissions from its sourcing and production processes. There are more sustainable options available, with an increase in concrete recycling which can be used to make “green” concrete.

What Types of Concrete Blocks Are Available?

There are a range of concrete blocks available within the UK, with solid options available in different densities, and hollow blocks that can be filled with liquid concrete or reinforced metal.

  • Dense Concrete Blocks: A dense concrete block will be designed for specific strength-based uses, such as within load-bearing walls or as the foundation of a building. Heat can pass through them easily, meaning they offer worse levels of thermal insulation.
  • Lightweight Concrete Blocks: Sometimes referred to as a standard block, lightweight concrete blocks have a lower level of strength compared to dense options, but offer better thermal insulation at a lighter weight. 
  • Aerated Concrete Blocks: The lightest solid block available, aerated blocks will have a lower density, meaning that heat takes longer to pass through them. They will offer the weakest strength of the three.
  • Hollow Concrete Blocks: These blocks will be used for more heavy-duty installations, with their large holes filled with poured concrete or steel poles. This can be used to make the strongest concrete block buildings.
  • Decorative Concrete Blocks: For external options, there will be both structural and visual blocks available. Hollow blocks can be produced with a textured face intended to give a more pleasing look externally, either imitating natural rock or patterned. Visual concrete blocks can be used within a garden, for non-structural applications, often hollowed in a specific pattern.
  • Concrete Paving Blocks: Solid concrete blocks can be made in different sizes, intended for use within exterior paving, either as a driveway or walkway.

What Size Are Concrete Blocks?

Unlike clay bricks, there are a variety of concrete block sizes available on the market. So while a standard size would be 440mm in length, 215mm in height, and 100mm in width, you will find a variety of options including larger blocks. The 440mm x 215mm face size is commonly sold in different widths, ranging from 75mm up to 215mm, with 140mm width as another popular choice for dense concrete blocks.

How Many Concrete Blocks Are Needed Per M2?

For the standard size quoted above, 11 standard blocks would be needed to build a 1M2 wall. This is considerably less than the 48 standard clay bricks needed to cover the same space, demonstrating why the labour costs for concrete blocks should be lower.

A construction worker holding a trowel with weatherproofing mortar, cement and concrete for concrete blocks to build a wall.

How Are Concrete Blocks Used in Construction?

Concrete blocks can be used for most building projects, offering benefits such as strength, fire resistance, and affordability.


Concrete blocks are a popular choice for quickly building houses within the UK. They offer strength, consistency, and quick installation. Modern concrete blocks are available with pigments to more closely mimic the look of a clay brick, but there are also options to cover exterior walls with panelling, a smooth concrete finish to be painted, or a small clay brick wall around the exterior.

Commercial Buildings

Concrete blocks are also used for commercial buildings, with reinforced hollow bricks a great way to build load-bearing walls for larger constructions. They offer solid insulation, and great fire resistance, and are affordable products that can be decorated in many ways to give a pleasing appearance.

Fire Rated Partition Walls

Another use for concrete blocks is to create partition walls designed to slow the passage of fire. Often partition walls within buildings will be hollow, built from timber studs and plasterboards. Using concrete blocks can help to create a safer building, useful for commercial projects.

What Is the Price of Concrete Blocks?

Building Materials Nationwide offers a range of concrete blocks for sale through our website. View some of the latest prices below.

  1. Low Stock In Some Areas - Contact Us Prior To Ordering

    • Crushing strength 7.3 N/mm²
    • Fire rating A1
    £1.89 £2.27
  2. £1.78 £2.14
  3. £3.72 £4.46

View All Thermal Insulation

High-Quality Concrete Blocks For Sale

Building Materials Nationwide works with professionals across the country, offering a wide range of building supplies delivered to them. We have a selection of concrete blocks available, with dense, hollow, and aerated options for sale. Our goal is to remove the hassle of sourcing supplies, offering everything needed in one place, delivered across the country at competitive prices. For customers within the building industry, we also offer trade accounts, giving you access to our network of suppliers, our express delivery options, and your own dedicated account manager. Sign up for a trade account through our website today or send us your questions using the below contact form.

    * These fields are mandatory