Question 1

1. What are lightweight concrete blocks?

Accepted Answer

Lightweight concrete blocks are masonry blocks made using lightweight aggregates or aerated concrete technology to reduce overall block weight compared with dense concrete blocks. They ‘re commonly used in UK construction for cavity walls, partitions, foundations, and some external wall applications.

Question 2

2. What are lightweight concrete blocks typically used for?

Accepted Answer

Lightweight concrete blocks serve a multitude of construction needs, primarily forming internal walls and partitions within diverse building types. Despite their lower weight, many lightweight concrete blocks remain suitable for load-bearing walls, partitions, cavity wall construction, and some below-ground applications when specified correctly. Their thermal efficiency also makes them a popular choice for the inner leaf of external cavity walls, aiding in insulation.

Higher-strength varieties can be used for load-bearing walls, while their acoustic properties are valued in party wall construction. Additionally, they can function as infill within beam and block flooring systems and (with appropriate damp-proofing) certain below-ground wall applications.

Question 3

3. What’s the difference between lightweight concrete blocks and standard concrete blocks?

Accepted Answer

The primary difference between lightweight and standard concrete blocks lies in their density and composition. Standard concrete blocks utilise dense aggregates like crushed rock or gravel, resulting in a heavier, more robust unit with higher compressive strength, typically favoured for substantial load-bearing applications.

Conversely, lightweight concrete blocks incorporate lighter aggregates, such as expanded clay, shale, or slag, or are aerated through a chemical process, yielding a significantly less dense block. This reduced density translates to easier handling, improved thermal insulation – a crucial factor for UK energy efficiency regulations – and often better acoustic performance compared to their standard counterparts.

Question 4

4. Are 'lightweight breeze blocks' the same as lightweight concrete blocks?

Accepted Answer

The term ‘breeze block’ is often used interchangeably with lightweight concrete block in the UK, although there is a historical difference between the two. Traditionally, breeze blocks were concrete blocks made using clinker or ash aggregates, sometimes known as “breeze”, which reduced the overall block weight compared with dense concrete.

Modern lightweight concrete blocks achieve lower weight using a wider range of manufacturing methods and materials. Some use lightweight aggregates, while others are aerated concrete products such as aircrete blocks. These modern blocks serve many of the same purposes as traditional breeze blocks, including cavity walls, partitions, and general masonry construction.

In practice, many builders still use the term “breeze block” informally to describe lightweight masonry blocks. However, most modern lightweight concrete blocks are not made from traditional breeze or clinker materials, even though they perform a similar role on site.

Lightweight concrete blocks

Thermalite Solid Hi-Strength Block 7.3N 100mm

Plasmor Fibolite Solid Lightweight Concrete Block 3.6N 100mm

Thermalite Hi-strength Block 7.3N 140mm

Forterra Fenlite Solid Lightweight Concrete Block 7.3N 100mm

Plasmor Aglite Solid Block 4.2N 100mm

Lightweight Solid 7.3N Block 440 X 215 X 140 mm

Plasmor Fibolite Solid Lightweight Concrete Block 7.3N 100mm

Thermalite Solid Part Wall Concrete Block 4N 215mm

Thermalite Solid Shield Block 3.6N 140mm

Lignacite Block 440mm X 215mm 3.6N 850kg/m3

Thomas Armstrong Solid Ultralite Concrete Block 3.6N 100mm

Thermalite Solid Shield Block 3.6N 50mm

CCP MODULITE SOLID LIGHTWEIGHT 100mm 7.3N 301410