How to Protect Granite, Marble, and Other Stone Countertops from Staining and Etching
As we’ve discussed in previous blog posts (that you can read here), the first step in protecting and maintaining your countertop surface is to understand how staining occurs in the first place.
As a quick recap: all natural stones are porous and will absorb liquids if left on the surface for too long. How quickly your chosen surface accepts stains is a function of 1) the porosity of your stone and 2) the size and shape of those pores.
But rest assured, for as we have done with much of the natural world, mankind has tamed the world of stone with the creation of sealers, the great equalizer in stone performance.
However, In the same way that Mother Nature often reminds us that we are but guests on her planet, a different type of stone surface damage called “etching” manages to elude our engineering prowess.
Is it a stain, or do you have “etching”?
Staining is the most common form of damage on natural stone countertops, but it can be commonly confused with “etching,” which is actually not a stain but a chemical reaction that occurs on the surface of stone. Etching is characterized by a dark discoloration of the stone in the damaged area. Still, if you own a darker-colored countertop, it may be difficult to distinguish by appearance alone.
To differentiate between an etch and a stain, run your fingers over the surface of the discoloration. If you feel an indentation, or if the stone seems to have a rougher texture, this is a good indication of etching. Remember: you won’t be able to feel a stain.
What is etching?
So, how can a chemical reaction take place on the surface of your countertop? After all, you and your Fight Club buddies gave each other chemical burns on someone else’s countertop.
The answer is that many food and beverage products, as well as many household cleaners, have high acidity; that is, they have pH levels that are lower than 7. We won’t get too off topic here, but liquids with a pH lower than 7 are acidic, and liquids with pH higher than 7 are alkaline (or “basic.”) Liquids with a pH of exactly 7 are neutral. Ever seen the label on a cleaning product that says “pH Neutral”? If not, it’s probably time to switch cleaning products!
Etching occurs easier on some stones than others. For instance, granite contains alkaline minerals, so If acidic liquids are in contact with the surface of your granite for a long enough period, a chemical reaction can occur, and an acidic liquid will begin to eat away at the granite’s surface.
But stones like marble, limestone, travertine, and onyx are “calcareous,” which means they’re comprised mostly of calcite, a composition of calcium carbonate that’s highly reactive to acids. If you’re a marble or travertine owner, your countertops are more susceptible to etching, so you’ll need to pay extra attention to the length of time that liquids linger on the surface.
Your first move to prevent etching is to ensure that the product you’re using to maintain your countertop isn’t damaging your countertop. Many cleaning products on today’s market can and will wear down your stone surface over time. You must use surface cleaners that are “pH Neutral.”
Don’t wait. Go and check right now!
How to fix etching on your stone countertop
Oh boy… it’s probably important to set expectations upfront: If you have etched countertops, the odds are high that you’ll need a stone restoration professional to fix the damage ultimately. But before you call in a pricey Pro, there is an option worth trying (that is, if you’re simply unwilling to live with the etch mark any longer).
There are products on the market designed to fix minor etch marks. The goal of a “polishing paste” is to return to the corroded etch mark, the same polished sheen that existed before the damage (and which exists on the rest of your countertop). It won’t reverse the damage, but it can do an excellent job of hiding it. Polishing pastes come with two caveats:
- The etching can’t be too severe. If the etch mark is deep into the countertop, it may not work.
- You must have polished countertops. Suppose you use a polishing paste on a honed countertop (i.e., a matte finish) or a textured countertop (i.e., any surface that isn’t smooth like glass). In that case, you’ll have a noticeably different finish in the repaired area.
The application is simple: Cover the damaged area with the paste and rub vigorously with a microfiber cloth. After several minutes of “polishing,” you may solve your problem. Also, note that, as is typical of most “fixes,” no matter how much hand polishing you perform, you probably won’t achieve a perfect sheen match.
If a polishing paste doesn’t do the trick, it’s time to call a stone care pro in your area. They may attempt a more advanced polishing methodology or recommend a total refinish if the damage is extensive. If you must go this route, expect to shell out $500 at the very minimum.
Prevent stains with penetrating sealer
“Penetrating sealers” are the most common sealers used on granite, marble, quartzite, travertine, and limestone countertops. They are designed to permeate the stone’s extremely small cavities to form a barrier against liquids that may otherwise seep into the pores.
Unfortunately, sealers lose their effectiveness over time, and reapplication is necessary. In addition, sealers can be worn down by the acids found in common beverages (sodas, coffee, wine, juices, etc.), extremely acidic liquids such as vinegar, and caustic household cleaning products.
Choosing and applying a penetrating sealer
When choosing a penetrating sealer, don’t be too concerned about whether the sealer is solvent-based or water-based. These are simply the mediums that carry the sealer into the pores of the granite. Water evaporates after depositing the sealer, and a solvent carrier simply flashes away.
What you want to pay attention to is the manufacturer's recommended reapplication frequency which can vary from every 3 months to every 6 months. The application itself is as easy as taking a rag and wiping down the surface of your countertops and then giving it a few hours to cure. However, failure to reapply can leave your granite’s pores exposed to liquid penetration.
Also, it’s important to note that manufacturer-recommended reapplications are suggested and likely suitable for most homeowners. Still, semi-professional chefs, children’s craft enthusiasts, or roadside lemonade stand proprietors would do well to increase the frequency.
If you need some guidance on which sealer to purchase, you can head down to your nearest hardware store or buy online. Anecdotally, most of the fabricators that we work with use Dupont’s Stonetech line of sealers— specifically the Stonetech Bulletproof penetrating sealer.
How can I be sure that my granite is ready for a new sealer application?
The simple answer here: it’s not going to hurt your countertop to reapply the sealer too soon after the previous application, so don’t wait if you have any concerns.
However, if you want some empirical evidence that your granite needs to be resealed, run the “water drop test”. Squeeze a few drops of water onto your countertop. Do they pool up on the surface, or do they soak right in? There’s your answer!
Fixing your countertop stain
Okay, don’t fret; we have options here. But can we all agree that life is good if we worry about countertop stains? Alright, back to business…
How to fix stained granite, marble, quartzite, etc.
If your granite is stained and not etched, removing the stain is straightforward. You’ll need to extract the liquid from inside the stone pores, so place your mouth on the stone and suck out the liquid as you would venom from a snake bite (just joking, don’t do that— you’ll look dumb). The concept for fixing your stain, however, is similar…
To extract the liquid from the stone pores, you must use a “poultice,” e.g., a highly absorbent paste. Spread the paste on top of the stained area, and over a short period, the paste will effectively absorb the trapped liquid from the granite’s pores. Voila! Stain removed! Many stone care companies manufacture a poultice stain remover but check out out option from StoneCare if you need a starting place.
The first step in fixing your damaged stone countertop surface is determining the extent of the damage: Do you have a stain, or do you have etching? The corrective action you’ll take depends on this answer.
Etching is harder to fix than staining, but you have an option. Unfortunately, if your attempt at fixing an etch mark doesn’t turn out the way you had hoped, your only option is to call in stone care professionals.
To take on staining, remember the wise words of General George Washington, who said that the best defense is a good offense. Be proactive and keep your countertops sealed. It’s super easy to do, just put a note on your phone calendar and wipe down your countertop with a penetrating sealer every 3-6 months and wipe up your spills within a reasonable amount of time.
Remember, if you’re unsure whether or not it’s time for reapplication of the sealer, splash some water on the surface of your counter. If it beads up, you’re sitting pretty. If it soaks in, take ten minutes and reseal your counters.
If your counters do stain, you can remove the stain by using a stone care paste called a poultice which absorbs liquid from the countertop pores. If you find a stain, it’s not the end of the world. Just do as we at CountertopSmart would do, blame the kids, and then get to fixin’!