Question 1

What considerations are important when choosing foundation blocks?

Accepted Answer

When selecting foundation or footing blocks, several crucial factors should guide your decision to ensure a stable and compliant build. Understanding the different foundation blocks sizes—such as 300mm versus 350mm—depends largely on the load-bearing requirements of your structure. Smaller blocks are typically suitable for standard walls, while larger, 350mm foundation blocks are better suited for supporting heavier loads or larger structures. Equally important is evaluating the soil conditions of your site, as poor soil may require denser or specially designed footing blocks to prevent shifting or settling over time.

Another vital consideration is the type of foundation block—whether aerated for thermal efficiency or dense for maximum strength—and how it aligns with your environmental conditions and project design. Additionally, consulting with a structural engineer or building professional can help determine the most appropriate block specifications, ensuring compliance with UK building regulations and promoting long-term durability. As a final consideration, while concrete blocks are commonly used, some projects may opt for traditional foundation bricks, especially in heritage or restoration work.

Taking these factors seriously at the outset helps prevent costly issues later and guarantees your foundation remains solid throughout the lifetime of your building.

Question 2

Foundation block types: When to use concrete blocks or footing blocks?

Accepted Answer

Understanding the distinction between concrete blocks and footing blocks is crucial for successful foundation construction. Concrete foundation blocks, renowned for their high compressive strength, are predominantly used in building walls, dividing partitions, and flooring applications. They are versatile, durable, and readily available in various sizes, making them an ideal choice for forming the main structure of a building’s foundation or load-bearing walls. Their excellent strength helps distribute loads effectively, providing stability and support for the upper levels or roofing.

In contrast, footing blocks are specifically designed for supporting substantial loads at the base of load-bearing walls or structural columns. Typically, these blocks are larger and more robust, constructed to sit directly on prepared foundations or stable ground. They act as the critical supporting layer that prevents settling or shifting over time, ensuring the longevity and safety of the entire structure. Footing blocks are often used in situations where ground conditions require additional reinforcement or where heavy loads, such as large extensions or multi-storey buildings, are anticipated.

Foundation blocks

Thermalite 300mm Trenchblock T&G 3.6N

Celcon Foundation Block Standard Grade Block - 440 x 215 x 300mm

Plasmor Aglite Solid Block 4.2N 100mm

Hi-strength Thermalite Trench Blocks 7.3N 300mm

Forterra Fenlite Lightweight Block 7.3N 100mm

Thermalite Hi-strength Block 7.3N 215mm

STOCKS INSULITE SOLID BREEZE BLOCK 100mm 7.3N

Plasmor Fibolite Solid Block 7.3N 100mm (Southern)

THERMALITE TRENCHBLOCK T & G 355mm 7.3N GRAB PK SHTG3551107GR

Besblock 100mm Insulite Solid 7.3N Standard