Selecting stones with Bellstone & Slate

Stone is a beautiful and time honored way to adorn a home or commercial building but stone by its very nature is variable in colour, texture and quality.

These characteristics make stone attractive as a building component but they can be beguiling as well because the vast majority of people cannot distinguish good quality stone from poor.

The durability of stone is determined by its strength and its capacity to absorb water both of which can be tested for. Good dense, hard stone that has low water absorption properties will be far more resistant to weathering if used outdoors and will be more resistant to salt attack if used around swimming pools. Stone with these qualities will also be less likely to stain, so maintenance costs are lower.

Sandstone is frequently used in outdoor applications such as swimming pool surrounds and recreation areas where the stone may be subjected to salt and chlorine attack from the swimming pools, food and drink stains from BBQ areas and even biological stains from dirt and leaves. The water absorption properties of different sandstones are often assumed to be similar whereas tests reveal huge variation.

The best performing sandstone may only increase its weight by 1% when inundated with water but some sandstone will be as high as 12% - the latter being inappropriate for use as outdoor paving unless repeatedly sealed.

The problem for the consumer is that unless they have experience in evaluating stone it is unlikely they will be able to differentiate good quality from bad. Buying beef at a butcher shop carries the same risks - you need to eat it first to assess quality.

Stone like beef, battles with a generic price tag that hides a huge range in quality. Thankfully beef is being tested (Meat Standards Australia), branded and packaged and comes with guarantees and the most professional suppliers of stone are making similar efforts to help consumers identify superior quality.

There are Australian standards for the flexural strength, water absorption, slip resistance and resistance to salt attack for all types of stone including sandstone (ASTM616) - these standards are the consumers best friend providing they can find a supplier that displays recent test results.

Bellstone & Slate P/L are Sydney based stone and slate specialists who routinely test all stone flooring products to ensure product safety and durability. For example, Willow sandstone, their most popular range of sandstone absorbs only 2.2% water whereas the standard is 8%; it is a strong (dry flexural strength 19.4 MPa), dense (bulk density 2421 kg/m3) stone with the highest slip resistance rating (wet pendulum 56V) and excellent salt resistance characteristics (weight loss 0.2% with no visible decay).

Indicative data such as this provides consumers with confidence to use a stone tile or paver for its intended purpose without taking unnecessary risks. Objective information on stone also empowers consumers when making important purchasing decisions.

Bellstone & Slate P/L provide all known test results on their stone tiles, pavers and cobbles on their web site http://bellstone.com.au/test_results.htm