Hello, readers! Welcome back to the Stonehouse Countertops blog! We’re pleased you’ve chosen Stonehouse Countertops for everything you need to know about custom countertop materials. We provide comprehensive deep dives into various aspects of the design and installation process, as well as helpful tips for choosing the best material for your home. Our goal is to equip you with the information you need to commission the perfect countertops! Stonehouse Countertops carries an array of granite, marble, quartz, quartzite, soapstone, silestone, limestone, travertine, onyx, glass, sodalite, slate, and porcelain materials in its inventory. In addition to countertops, we offer fireplace surrounds, patios, floors, and walls. Whatever your design goals, we’re happy to help you achieve your unique vision!

Our last article explained the process of quarrying natural stone, from beginning to end! How does raw material, embedded within the earth, end up donning your kitchen countertops? Quite simply, a multitude of labor-intensive steps must be taken to extract stone in a manner which will allow the stone to be used for commercial purposes. Updates in technology have allowed the extraction and fabrication processes to become both quicker and safer. As a result, consumers can enjoy natural stone at a relatively affordable price point. In our last article, we detailed the various methods by which stone is quarried, as well as cutting techniques which alter the final appearance of the stone. We didn’t stop there! We followed the stone blocks all the way through the fabrication process, giving you insight into how slabs are cut and polished. If you’re interested in the natural history of the stone featured within your home, How Natural Stone is Quarried is a great place to start! 

Today, we’ll be discussing how to seal countertops. No homeowner wants their countertops marred by stains. The condensation ring from a glass of water, the red-tinge from a spill of wine, the dark mark from a splash of coffee–it’s all no good. Depending on the type of stone material you utilize for your countertops, spills may not even be a consideration. Certain stones, such as quartz, are low-porosity and highly stain-resistant, making sealing a non sequitur. However, a majority of stones require regular sealing to ward off unattractive stains and marks. No homeowner–but especially an avid cooker–should live in fear of staining their countertops! That’s why today’s article is dedicated to breaking down the process of sealing your countertops. We’ll discuss which stone materials actually need this type of maintenance, as well as which don’t, before delving into which type of sealant is suitable for your needs. Finally, we’ll give an overview of how to seal your countertops and how often to ensure the seal is good. If you prioritize the maintenance of your countertops, they can stay looking brand-new for decades to come. We hope this article serves as a resource (don’t hesitate to bookmark)! 

Why is sealing countertops important?

Beyond protecting against just stains, sealants also fill the gaps between stone particles. These gaps, ordinarily, offer a hiding place for bacteria and food-borne pathogens. Unless your countertops are naturally nonporous, they could be harboring bacteria, no matter how well or how often they’re cleaned. Certain types of sealants can protect your countertops from bacteria overgrowth. Additionally, sealants can increase the longevity of your countertops, saving you money in the long run!

Which stone materials need to be sealed? 

As we mentioned, quartz is pretty low maintenance. Since it’s composed of over 90% quartz minerals and 10% resins, polymers, and pigments–the stone technically already has its own seal. Or, rather, the resins present in its composition effectively fill the space between the aggregate (i.e. quartz), creating a highly dense and low-porous material. Quartz is the material you’ll want to opt for if the idea of sealing your countertops even once sounds like a ton of work. That said, if you opt for quartz countertops, you’ll still have the option of sealing. While this won’t make much of a difference when it comes to fighting off stains, it can be done for aesthetic reasons. Sealed quartz is shiny and gives off a “clean” look. If you do decide to apply a seal, do your research first. Different types of quartz use different chemicals and pigments, some of which may react adversely to certain sealants (over time). Similarly, spraying liquid sealants onto quartz isn’t the best idea, as the liquid will have nowhere to go and simply rest on top of the surface. Honestly, you’re probably better off forgoing sealing quartz altogether, as even white quartz will stay pristine so long as it’s kept clean. 

Another stone material that has incredibly low porosity and, thus, does not need to be sealed is soapstone. Soapstone doesn’t stain, but it does darken. For this reason, instead of sealing, soapstone owners apply a minuscule amount of mineral oil to the countertop’s surface. This application occurs once per month during the first year and then once a year thereafter. The oiling helps to even the darkening process, which means if a ring were to be left on the countertop from cup condensation, eventually the stain would blend with the rest of the countertop. However, it’s very unlikely soapstone would stain at all. Therefore, oiling soapstone is also entirely optional. Some owners prefer the visual depth supplied by allowing the soapstone to develop a patina over time. It’s an aesthetic choice, rather than a practical one. 

That said, almost every other kind of stone will need to be sealed to prevent staining and bacteria growth. Both marble and granite are porous, though not as porous as limestone, travertine, and slate. Since porosity is the ultimate determination of how “stain-able” a stone is, you can test the porosity of your stone by performing a simple test. Place a few droplets of water onto the stone in question and see how long it takes for the stone to absorb the water. (This test is, of course, for stones which have never been sealed.) Stones which readily absorb the water are highly porous. Stones which take their time absorbing the water are somewhat porous. Only stones which do not absorb the water could be considered non-porous. Stones like marble, limestone, and travertine should be sealed more often, as in once every six months. Meanwhile, granite can be sealed once a year. 

Types of Sealant

There are three types of sealant, each distinct in its method of protection. The first kind of sealant is known as a surface sealant. Surface sealants are the most temporary kind, as they are easy to remove. They act almost as a film, sitting on top of the top and blocking liquids from coming in contact with the surface of the stone. You’ll want to ensure the surface sealant you choose is specifically designed to be used on natural stone, as some surface sealants are formulated for use on floors. This type of sealant will begin to peel and that’s how you’ll know it’s time for a new coat. 

For a slightly more permanent option, you’ll want a penetrating sealant. A penetrating sealant does just what its name suggests and penetrates the surface of the stone. Since the sealant sinks into the microscopic openings between the stone’s particles, it’s not easy to remove and will not peel. Finally, there’s the impregnating sealant. This type of sealant is best applied by a professional. It can last for several years and can be used on outdoor stone materials. If you read our article on outdoor countertops, you know UV rays can pose a particular threat to certain stone materials, causing them to discolor over time. Well, most impregnating sealants are also impregnable by UV light!

Depending on the finish of your countertops (i.e. honed, polished, flamed, etc.), you might require a different type of sealant. Beyond surface, penetrating, and impregnating, sealants are also differentiated by their ingredients. Surface sealants are often water-based, with polymers such as acrylic, whereas penetrating sealants are formulated with solvent-based polymers. Impregnating sealants often use resin dissolved in water or petroleum-based solvents to create their strong seal. Sealants also tend to contain chemicals such as ethanol and other volatile organic compounds, which can leave your home smelling toxic. Natural or non-toxic sealants exist, but you should read reviews before purchasing to ensure they can be used safely on your type of stone. 

What are you waiting for? Go ahead and seal your stone countertops! We hope this article has been informative and helpful. At Stonehouse Countertops, we are willing and able to work with you to your specifications. We offer a wide range of different materials and always have someone on hand to answer your questions! Don’t hesitate to reach out for a consultation or for help forming a plan. We want to ensure your vision becomes a reality! Until next time—thanks for reading!