stone standard

Setting the stone standard

Marshalls plc ammonite logo Marshalls Plc Monday 5th October, 2015

Using Indian sandstone paving or flags for patios and paths in our gardens – is a mark of luxury and style. But there is much more to this stone then first meets the eye, not least because there are hundreds if not thousands of varieties, which means there can be wild differences in quality.

Marshalls’ stone expert Chris Frankland recently carried out tests on a number of randomly selected Indian sandstones, available on the market today, and discovered that half did not meet the British Standard. . All the stone paving we supply meets or exceeds the British Standard, which we refer to as the Stone Standard.

So while some Indian sandstone may look like the perfect fit in the merchants’ yard, or a glossy brochure, it might not be up to the task of withstanding the rigours of the British climate. Unfortunately, it’s not easy to tell the difference, but a trained eye may be able to spot a few tell-tale signs that the product is lacking.

Sandstone – looks can be deceptive

Sandstone is a natural product that can wildly vary in appearance and performance and while there are a raft of factors involved in determining whether or not a particular cut is fit for purpose, the following three are key:

  • Water absorbency. A sandstone with a high level of water absorbency – that is, one that draws in too much water – will be more likely to turn an unsightly shade of green over time, and is also more vulnerable to frost. Look for stone with 2.5% water absorbency – any higher than this means the stone is too porous and unsuitable for use as paving.
  • Flexural strength. Stone that has a low flexural strength of less than 12mpa (megapascals – the unit of measuring tensile strength) is not only less likely to stay-protected against the harsh British winter, but also more likely to get damaged in transit or while you’re building your patio project.
  • Frost resistance. A stone that becomes weakened when subjected to frost is not going to keep its aesthetic appeal for long in typical UK weather conditions.

Every one of our products more than matches these requirements, making our stone some of the most capable in the UK, whatever the job.

Ask the right questions

Before you buy any stone product, you should make sure the manufacturer has fully tested it for the three measures we’ve listed above – ask your installer to see an up-to-date test certificate. Only this will tell you that your new garden feature won’t turn green or crack in the rain and frost.

The process of purchasing the right stone is more than just choosing the right shade and quantity – there are many factors to consider in making sure that what your materials have been thoroughly tested for quality, and ethically sourced for a hardwearing, long-lasting and guilt-free driveway.