Stone Initiatives has developed a stain-resistance test method (SI-STAIN-09) specifically for evaluating sealers on dimension stone. The test results will provide you with information on the natural stain resistance of the stone when exposed to a range of common staining agents and its performance after sealers have been applied.
Article: Jim Mann
Stone would have to be the most versatile of building materials. We can build with it, walk on it, bathe in it and even eat off of it and advances in modern processing methods have made stone accessible to everyone. The ubiquitous use of stone throughout our homes, workplaces and public spaces has also brought the need for updated cleaning and care regimes to maintain its beauty.
A crucial part of the care and maintenance practice for many stone types is the use of a sealer to improve the stone’s resistance to staining. When you are met with the wide range of sealers on the market, the selection of the right sealer for the job can be daunting. Do I choose a surface sealer or an impregnating sealer; do I want a ‘wet look’ finish or a natural finish? These are just some of the choices you may be met with.
Sealer selection is truly a case of ‘horses for courses’. Stone type, surface finish and location all need to be taken into account when selecting a sealing system, but most importantly you need to know what you are protecting your stone from. As an example, a light grey granite on a restaurant floor will be exposed to red wine, coffee and oily foods. The sealed surface will also need to have adequate slip resistance to meet statutory requirements. In this case an impregnating sealer would be best suited as this group of sealers does not significantly alter the slip resistance of the surface. Choosing a sealer with good oil repellency would also be important as grey colours tend to highlight oil stains.
Understanding the limitations of sealers
Understanding the limitations of sealers is also important. Sealers are designed to improve the natural stain resistance properties of stone – they will not provide 100% protection against all stains in all situations. As an example, an impregnating sealer will not prevent marble or limestone being etched by acidic solutions such as wine or soft drinks; impregnating sealers are designed to reduce the absorption of stains and cannot provide complete protection to the exposed surface. Surface sealers (such as acrylics and polyurethanes) provide excellent surface protection by forming an impermeable barrier. The drawback of this feature is that any moisture below the sealed layer cannot escape and peeling of the coating may follow.
Selection of the correct protection system for your stone really is a case of ‘horses for courses’ and there is no one product that will work in all situations. Determining the stain resistance of the stone without a sealer and with a range of sealer products provides an insight into the performance of the stone and can ensure you choose the right product.
Test method for evaluating sealers
Stone Initiatives has developed a stain-resistance test method (SI-STAIN-09) specifically for evaluating sealers on dimension stone. The test results will provide you with information on the natural stain resistance of the stone when exposed to a range of common staining agents and its performance after sealers have been applied. The test covers resistance after a long term (e.g. if the surface was only cleaned once per day) and short term dwell time (if the spill was clean up relatively quickly).