Why Portland Stone Supplied by Albion Stone Allows for a Lower Factor of Safety

One of the major advantages of choosing Portland Stone from Albion Stone is the ability for designers and engineers to apply a lower factor of safety compared to stone supplied by other sources. This isn't about cutting corners—it’s about confidence through data.

At Albion Stone, we’ve made a long-standing commitment to quality, testing, and transparency. Since 1988, we’ve carried out over 12,000 individual laboratory tests in collaboration with leading institutions such as the Building Research Establishment (BRE) and Sandberg. These tests cover every relevant property of the stone—compressive strength, flexural strength, durability, freeze-thaw resistance, and more—allowing for a precise and reliable understanding of how our stone will perform in real-world applications.

Confidence Backed by Data

When stone performance is known and proven to such a degree, structural engineers can make informed decisions about the material’s use, including safely applying a lower factor of safety in their calculations. This is significant because a lower factor of safety can reduce the required stone thickness, saving on material cost and reducing overall building weight—without compromising structural integrity.

An example is provided in BS 8298-2, the British Standard for the design and installation of natural stone cladding. In a worked example using our Jordans Whitbed, a factor of safety of 4.2 is applied. This is only possible due to the depth and reliability of our technical data.

This example uses:

• LEV results;
• Measurement in accordance with BS EN 13161 (only applicable to the flexural design calculation);
• Test data from dry stone samples;
• Historical data available for over 10 years;
• Sample cut in orientation as intended for project; and
• Freeze-thaw testing shows less than 5% loss after 14 cycles. 

Why This Matters

Most suppliers cannot provide such a comprehensive suite of test results. Without this assurance, engineers must assume more conservative values—resulting in higher factors of safety and thicker, heavier stone panels. In contrast, Albion Stone’s transparency and commitment to testing enable more efficient, optimised design.

All our test results are publicly available through our:

• Declarations of Performance (DoPs)
• Technical Data Sheets
• CE/UKCA Certificates

This detailed documentation removes ambiguity and gives design teams clear, current, and accurate data to work from, removing the need to build in unnecessary conservatism.

Setting the Standard

As we shared in our recent news story on quality and testing, we believe that trust in natural stone begins with evidence. That’s why every block of stone we supply can be traced back to its test data, and why leading architectural and engineering practices continue to specify Albion Stone for both heritage and contemporary builds.

Tags: Test Factor Of Safety