Freeze Thaw Testing for Stacked Stone Veneer
When we we first started Norstone in late 2005 we were focused on developing the market around our first distribution center in Northern Florida. Thanks to the internet and some great photography of the product taken in the early days in Australia where the product was first marketed, we quickly started selling product all over North America. Early on we got asked the question about whether our products were suitable to be used in an exterior application in an area that experiences lots of freeze / thaw cycles during the winter. The concern is that moisture that is either trapped in the stone or in the installation itself can expand and then contract during these freeze / thaw cycles creating cracking in the stone, separation, breaking, and even causing the stones to fall off the wall.
As entrepreneurs, we were still “learning on the fly” and thus reached out to experts in the industry to learn more about how our stone could be tested and certified for this type of application. There are best practices for installing stone and tile in cold climates, but before you even consider laying the first stone you should verify if its tested and rated for freeze / thaw climates. We learned through various contacts in the stone industry that the ASTM C67 test for dimensional stone veneer which was used as the industry standard in the stacked stone industry for freeze / thaw testing. This test involves providing samples of the stone to an independent lab where they take the samples put them in a water bath, freeze them overnight in a temperate controlled cabinet and then allow them to return to room temperate the following day. This process is repeated 50 times for the ASTM C67 test to be completed and the samples are inspected at the beginning, after every 10 cycles, and then again at the end to note any cracking. The test defines a crack as a fissure or separation visible to a person with normal vision from a distance of one foot.
Probably the hardest part about the ASTM C67 test is waiting for the results! Since the samples get frozen overnight and the test requires 50 cycles, the testing takes about 10 weeks plus any time needed to get the samples to the lab and then adequate time for the lab to produce the report at the end of the testing process. To date, all of the stones we have sent to the independent lab that does our freeze / thaw testing have passed without any fissures of separations. Not all of our products are rated suitable for exterior freeze / thaw applications, notably a trio of colors in our XL Rock Panel Series – Aztec, Sierra, and Pearl. Due to the high content of mica in these particular stones we knew from speaking with various geologists and stone experts that they wouldn’t perform under the stresses of an exterior freeze/ thaw climate.
The results of freeze/ thaw testing for all of our products can be found on the “Installation Guide” page of our our website. Towards the bottom of this page there is a section called “Technical Library” and a sub heading in the library called “Testing Data”. Any of the Norstone team members can also provide this information via email if requested.
Thanks for learning more about the process that our products undergo to be tested and certified for use in freeze / thaw climates. If you live in or specify products for these types of climates, be sure to check all for freeze / thaw suitability for all of the products on the exterior envelope of your project. And as always, if you have any technical questions concerned our stacked stone products, or any stacked stone questions in general, please contact us via email or call our main line and ask for tech services and we’ll do whatever we can to help!