Operating in the UK, we are all familiar with the challenges posed by the Great British weather. When working with masonry blocks, adverse weather conditions—particularly freezing temperatures—require careful consideration.
Most masonry blocks are frost-resistant; however, this performance is closely linked to the block’s density and compressive strength. Blocks with a minimum compressive strength of 7.3 N/mm² and a density of 1,500 kg/m³ are generally suitable and recommended for use in freezing conditions. Even so, appropriate measures must be taken to protect materials from the elements. Any products below these density and strength values may require increased protection and consideration during the winter months.
In low temperatures, especially during frost, masonry blocks can become saturated with moisture. When absorbed water freezes, it expands, creating internal pressures within the block. This expansion can lead to cracking, surface deterioration, or long-term durability issues.
For masonry units used in high-exposure conditions, it is recommended that they are kept free from excessive moisture and adequately protected throughout construction. This can be achieved by using thermal blankets, protective coverings, or temporary enclosures to shield materials from the elements and help maintain stable temperatures.
Key points to consider:
- LABC and NHBC guidelines specify a minimum compressive strength of 7.3 N/mm² for blocks used in external walls exposed to frost.
- Concrete blocks should have a minimum density of 1,500 kg/m³ to be considered frost-resistant.
- Frost damage can be reduced where walls are naturally protected by surrounding buildings or environmental features.
- It is generally recommended to avoid laying blocks when temperatures fall below 3°C, unless appropriate precautions are in place.
- In conditions where freezing temperatures and wet weather are expected, ensure blocks are fully covered and protected from the elements.
If you are planning to use our masonry blocks on your next construction project, please feel free to contact our team. We are happy to answer any questions regarding product performance and help you select the right specification to meet your project requirements.