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An introduction to dense concrete blocks: Their properties, benefits and uses

Posted by Nick Franks

Dense concrete blocks are a versatile material for builders. To find out why, take a look at our detailed introduction to this adaptable product.

Not all concrete blocks are made alike. In fact, their densities can be very different, ranging from lightweight to dense. But what exactly are dense blocks, and what can they be used for? In this introduction, we take a look at the advantages and applications of dense blocks. 

What are dense blocks?

A dense concrete block is a durable construction material that is ideal for many applications, including foundation walls, retaining walls, party walls and other load-bearing structures. 

This is because it is strengthened by its higher density. A dense concrete block typically has a density of 1,800 to 2,100 kg/m3 whereas a standard medium dense block, such as Lignacite, has a density of 1,300 to 1,550 kg/m3. This higher density makes the blocks very robust, durable and strong, perfect for when you need extra support.

The properties of dense blocks

What is the strength of dense concrete blocks?

Dense concrete blocks are very tough and strong. Our dense concrete block range, Lignacrete, is available in compressive strengths ranging from 7.3 to 30N/mm². This makes them a great choice for load-bearing purposes in low-rise and high-rise buildings. 

How heavy is a dense concrete block?

Due to their higher density, dense blocks are heavier than standard concrete blocks. The wide range of dense blocks available means that their weight depends on exactly how dense they are and how large the block is. In our Lignacrete High Strength range, a midi-sized block with a strength of 17.5N/mm² weighs around 17.5kg per unit. 

What are dense concrete blocks used for?

The extra density of these concrete blocks makes them adaptable materials for all kinds of buildings. Here are just a few examples of their applications and how you can use dense blocks in your next project:

• Load-bearing walls: Dense concrete blocks are commonly used in construction for load-bearing walls due to their high strength and durability. They provide structural support to buildings and can withstand heavy loads. For instance, our dense Lignacrete blocks were used in the construction of The Cheesegrater in London.
• Foundations: These blocks are ideal for building foundation walls as they offer excellent stability and frost resistance. They help distribute the weight of the structure evenly, ensuring a solid base for the building. See our case study of The Paddocks to see how our dense Lignacrete product was used in a residential project.
• Retaining walls: Dense concrete blocks are often used in the construction of retaining walls to hold back soil and prevent erosion. This is because their weight and strength make them effective in resisting lateral pressure from the retained earth. In particular, hollow dense blocks are often a popular choice for this application. They can be strengthened even further by adding vertical reinforcing bars into the cores of the blocks.
• Partition walls: Dense concrete blocks make excellent partition walls. Their density means that they offer very effective sound insulation. This provides privacy and acoustic comfort in all kinds of buildings, such as residential, commercial and industrial spaces.
• Inner and outer leaves of external cavity walls: Dense concrete blocks are well-suited for both the inner and outer leaves of external cavity walls. As the outer leaf, they provide protection against the weather and physical damage, while their high density ensures effective soundproofing from external noise. As the inner leaf, dense concrete blocks offer structural integrity while also providing thermal mass for improved energy efficiency and acoustic insulation.
• Block and beam floors: Dense concrete blocks make great infill blocks for block and beam flooring. 

The benefits of dense concrete blockwork

Dense concrete blockwork has a wide range of advantages. Here are just a few of them:

1. Strength and durability: Dense concrete blocks are strong and durable, making them capable of withstanding heavy loads and damage from external forces. This strength ensures long-term structural integrity.
2. Thermal insulation: Dense concrete blocks, in conjunction with appropriate cavity insulation, can provide adequate thermal insulation to meet Part L Building Regulations. Their thermal mass also protects against temperature changes within buildings. This is because they have the ability to absorb and release heat. For instance, during warm weather, unwanted heat is absorbed by the thermal mass of exposed floors and walls to reduce the risk of overheating.
3. Soundproofing: The density of concrete blocks helps dampen sound transmission, making them effective at reducing noise levels between rooms or from external sources. This feature enhances privacy and comfort in residential, commercial and industrial buildings. 
4. Fire resistance: Concrete blocks offer excellent fire resistance, providing a barrier against the spread of flames and heat. 
5. Versatility: Dense concrete blocks are versatile building materials suitable for loadbearing walls, foundation walls, retaining walls, partition walls and external cavity walls. 

Find the right dense block for your project

Dense concrete blocks are a fantastic building material with many advantages and applications. You can learn more about our dense Lignacrete range on our website, or get in touch with our Quoting Team by calling 01842 778485 today.