Natural Stone Porous Materials Protection Cleaning D.I.Y.

NIST: Building the foundations of stone surface protection

The effects of the weather on rock is plainly visible on the NIST Stone Test Wall.

It's a given that when you make use of natural stone outside, you've got to prepare for all kinds of potential damage – not the least being the gradual impact of weathering, as wind and rain batter the stone and water penetrates its surface.

That's why, for decades, companies like Dry-Treat have invested in innovation, working to utilise the latest technology in order to keep stone immaculate through surface cleaning and protection. Thanks to this commitment to innovation, Dry-Treat has come up with products such as STAIN-PROOF Original™, Oxy-Klenza™ and Rejuvenata™, all aimed at providing solutions for all the different situations natural stone might find itself in.

But, you might wonder, where did this impetus come from? Given the success of Dry-Treat's sealing and cleaning products, it's worth paying tribute to one of the roots of the modern stone protection industry: the National Institute of Standards and Technology (NIST) Stone Test Wall.

The NIST Stone Test Wall

The NIST Stone Test Wall sits on the site of the NIST in Gaithersburg, Maryland, at its southwest end. Standing at nearly 40 feet long, 13 feet high and around 2 feet thick at its granite base, the wall would already be impressive enough were it not for its design.

What makes the NIST Stone Test Wall such a unique monument, however, is its checkered pattern, with each tile made from a different type of individual stone. The wall features 2,352 different stones both locally sourced and foreign, with more than 30 distinct kinds of stones and their many varieties represented – from marble strains to breeds of sandstone.

Of these 2,352 stones, on the wall you can see for yourself 2,032 kinds of domestic stone from 47 states, and 320 stones from 16 foreign nations – including Argentina, Thailand and even Bermuda.

The history of the wall

According to Masonry, the Official Publication of the Mason Contractors Association of America, the stone was originally the brainchild of a committee of the American Society for Testing and Materials (ASTM), who wanted to study the effects of weathering on a variety of stone. They teamed with what was then known as the National Bureau of Standards (NBS, which later become the NIST) to construct the wall in Washington DC in 1942. In 1977, it was moved to its present location.

In fact, however, the project had its roots in a much earlier initiative. All the way back in 1880 – over 130 years ago now – the National Museum in Washington DC and the Census Office teamed up to collect building stone samples from various quarries for the purposes of study.

These stones were combined with the Centennial Collection of US building stones that had been originally compiled for the 1876 Centennial Exhibition in Philadelphia, and various stones compiled from other countries. Moving from site to site, it found a permanent home when the ASTM decided to use it to build the NIST Stone Test Wall.

The NIST Stone Wall provided, and still provides, one of the best and most comprehensive opportunities to study the effects of weathering on stone, laying the foundation for the work that companies like Dry-Treat would later build on (pun intended).

A first-hand look at the effects of weathering

The sheer staggering variety of stone on the wall can be at first overwhelming. Whatever the type of stone and its damage from weathering you want to study, it seems you can find it on the wall.

Take, for example, the heavily eroded Spanish sandstone that sits on the wall's front face, an eternal reminder of sandstone's vulnerabilty to water damage. Or look at the many different types of Kentucky limestone, all in different stages of weathering. You might even examine the several samples of Utah marble, ranging from pristine to chipped and cracked.

It was the data collected from projects like this that today allows us to more effectively take care of our stone surfaces. Dry-Treat salutes these early pioneers of stone, without whom later innovations in surface protection like STAIN-PROOF Original™ could not have come to fruition.

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