Does Your Stone Need Sealing?
Short answer: it depends on what your countertop is made of. Natural, porous stones — marble, granite, quartzite, travertine, and limestone — should be sealed, at installation and periodically after that. Engineered quartz and porcelain / sintered stone are non-porous and never need sealing. Sealing doesn't make stone waterproof or bulletproof — it slows how fast liquids soak in, which buys you time to wipe up a spill before it stains. It does not prevent etching on marble. The easiest way to know when it's time to re-seal is the water test: drip a little water on the surface, and if the stone darkens within a few minutes, the pores are absorbing it and it's due. How often varies by stone and how hard the surface works — anywhere from once a year to every few years. Here's how to tell what you have and exactly what it needs.
By Leo Chuahy · Prime Surfaces — founder, with a stone-slab sourcing background (Brazil, Spain & Italy)
Which countertops need sealing — and which don't?
The dividing line is porosity. Porous natural stone should be sealed: marble, granite, quartzite, travertine, and limestone all have a pore structure that can absorb liquids, so they're sealed to slow that down. Non-porous surfaces never need sealing: engineered quartz and porcelain / sintered stone are sealed by their own manufacturing — there's nothing for a sealer to soak into. Soapstone is the odd one out: it doesn't need sealing to resist stains, though many owners oil it to even out its patina. When in doubt, ask us what your specific stone wants.
What does sealing actually do (and not do)?
A sealer is an impregnator that sits just below the surface and slows absorption. Think of it as buying time, not building armor. It gives you a window — often several minutes — to wipe up wine, oil, or coffee before it soaks in and stains. What sealing doesn't do matters just as much: it doesn't make stone waterproof, it doesn't prevent scratches, and on marble it doesn't prevent etching — the dull spots acids leave are a chemical reaction with the stone itself, which no sealer can stop. Sealing is about staining, full stop.
How do you know when it's time to re-seal?
Don't guess — use the water test. Drip a small amount of water on the surface in a few spots and watch. If the water beads up or sits on top, your seal is doing its job. If the stone darkens within a few minutes, the pores are drinking it in and it's time to re-seal. You can do the same test with a drop of mineral oil for a stricter check. Areas around the sink and cooktop wear faster than a low-use corner, so test the hardest-working spots.
How often should you seal quartzite, marble, and granite?
There's no single number, because it depends on the stone's density and how hard the surface works — the water test always beats a calendar. As a rough guide: dense granite and quartzite often go a year or several years between sealings; marble and other softer, more porous stones usually want it more often, sometimes annually in a busy kitchen. A honed or leathered finish can absorb a touch faster than a polished one. A stone bathroom vanity that sees light use may need it far less often than a kitchen island.
How do you seal a countertop yourself?
It's a straightforward job. Start with a clean, dry surface. Apply a quality stone-impregnating sealer evenly with a soft cloth, let it dwell for the time the product specifies (usually a few minutes) so it penetrates, then wipe off all the excess before it dries — leftover sealer can leave a hazy film. Some stones benefit from a second coat. Always follow the sealer's directions and test in an inconspicuous spot first. If your stone is delicate, valuable, or you're unsure which product is right, it's worth having it done professionally rather than risking streaks.
Do quartz and porcelain ever need sealing?
No — and this is one of their biggest advantages. Engineered quartz and large-format porcelain are both non-porous, so they never need sealing and won't absorb stains under normal use. If a countertop salesperson tells you to seal your quartz, that's a red flag. Care is simply mild soap and water or a pH-neutral cleaner and a soft cloth. If low maintenance is your top priority, these two families are the easiest surfaces we install — there's a fuller breakdown in our porcelain vs. quartz guide.
Does sealing stop stains and etching?
Sealing greatly reduces staining by slowing absorption, but it doesn't make stone stain-proof — a spill left long enough can still soak in, and a sealer wears over time. And on marble and other calcium-based stones, sealing does nothing for etching, because etching is acid chemically dulling the surface, not a liquid being absorbed. The real protection is habits: wipe up acidic and oily spills promptly, use boards and trivets, and keep a sealed surface sealed. For the full care routine after a new install, see our countertop care guide.
FAQ
Do quartz countertops need to be sealed?
No. Engineered quartz is non-porous, so it never needs sealing and won't absorb stains under normal use. The resin that binds the ground quartz already makes the surface impervious to liquids, so there's nothing for a sealer to penetrate. If someone tells you to seal your quartz, that's a sign to ask questions. Everyday care is just mild soap and water or a pH-neutral cleaner and a soft cloth — skip abrasive pads and harsh chemicals like bleach and ammonia, and use a trivet since quartz can be damaged by high heat.
Does quartzite need to be sealed?
Yes. Quartzite is a natural, porous stone, so it's sealed at installation and re-sealed periodically to slow absorption and prevent staining. Dense quartzites can go a year or several years between sealings; the water test tells you when. Note that sealing protects against staining only — and since true quartzite doesn't etch, that's the main thing you're guarding against. Some stones sold as quartzite are actually softer marble that etches, so it's worth confirming what you really have.
Does granite need to be sealed?
Usually, yes, though it varies by the specific granite. Most granite is porous enough to benefit from sealing at installation and periodic re-sealing, but some very dense granites absorb so little that they need it rarely, if at all. Rather than following a fixed schedule, use the water test: if water dripped on the surface darkens the stone within a few minutes, it's time to re-seal; if it beads, you're fine. Areas around the sink and cooktop wear faster and should be checked first.
Does marble need to be sealed?
Yes. Marble is porous, so it's sealed at installation and re-sealed periodically — often more frequently than granite or quartzite because it's softer and more absorbent, sometimes yearly in a busy kitchen. Use the water test to decide. One crucial caveat: sealing marble reduces staining but does not prevent etching, the dull spots acids leave behind. Protecting marble is as much about prompt cleanup of acidic spills and using boards and trivets as it is about sealing.
How often should you seal natural stone countertops?
There's no universal number — it depends on the stone's density, its finish, and how hard the surface works. Dense granite and quartzite may go one to several years; softer, more porous stones like marble often want it more often. Rather than trusting a calendar, run the water test every so often, especially near the sink and cooktop where wear is fastest. When water stops beading and starts soaking in, it's time to re-seal. A low-use vanity will need it far less often than a kitchen island.
How do you test if your stone needs sealing?
Use the water test. Drip a small amount of water on the surface in a few spots — including the hardest-working areas near the sink and stove — and wait a few minutes. If the water beads or sits on top, the seal is still working. If the stone darkens where the water sat, the pores are absorbing it and it's time to re-seal. For a stricter check, use a drop of mineral oil. It's a two-minute test that takes all the guesswork out of when to reseal.
Does porcelain or sintered stone need sealing?
No. Large-format porcelain and sintered stone (brands like Neolith and Dekton) are non-porous and never need sealing — they're among the lowest-maintenance surfaces you can install. They resist stains, heat, scratches, and UV, and clean up with mild soap and water or a pH-neutral cleaner. The one thing to know about porcelain isn't maintenance but fabrication: its thin, hard slabs need a skilled installer to handle edges and seams, which is exactly the part a certified specialist takes care of.
Does sealing prevent etching?
No. Sealing prevents (or slows) staining, which is absorption — a liquid soaking into the stone's pores. Etching is different: it's an acid chemically dissolving a microscopic layer of a calcium-based stone like marble, leaving a dull spot. No sealer stops that reaction. If you have marble or another carbonate stone, the way to avoid etching is to keep acids off the surface and wipe up spills like lemon, wine, and vinegar quickly — and to consider a honed finish, which hides etching far better than a polished one.
Not sure what your stone needs?
Send us your project or your existing stone and we'll tell you exactly what care — and what sealing schedule — it really needs.