Sealing granite: when, how often, and how to test it

Does granite actually need sealing?

Yes. Granite is natural stone, and natural stone is porous to some degree, even the dense, tight-grained slabs. Sealing fills those tiny pores near the surface so liquids sit on top long enough for you to wipe them up instead of soaking in. It's not a one-time fix. It wears down over years of cleaning and use, so it needs to be renewed.

At Rocky Tops Granite & Marble, we seal every job at install with a top-shelf sealer, put on by installers we train to apply it right. A lot of companies install and hand you a bottle to do it yourself. We don't. The first seal, the one that matters most, is already done when your countertops go in.

The water test

This is the easiest way to check where your seal stands. Pour a small puddle of water, maybe the size of a quarter, on a clean, dry spot of your countertop. Let it sit for 10 to 15 minutes.

• If the water beads up and stays on the surface, your seal is doing its job.
• If it soaks in and darkens the stone, that's a sign the sealer has worn thin and it's time to reseal.

Run this test in a few spots, especially near the sink and stove where the counter gets wiped down most. Wear happens unevenly.

How often to reseal

Most kitchens need resealing about once a year. That's a general guideline, not a fixed rule. A few things push it faster or slower:

• Heavy use. A busy kitchen where someone's cooking daily wears the seal faster than a lightly used bar counter.
• Color and finish. Darker, denser granites can sometimes go longer between resealing than lighter, more porous ones. It varies slab to slab.
• Cleaning habits. Harsh cleaners or abrasive scrub pads break down sealer faster than a mild soap and soft cloth.

When in doubt, run the water test instead of guessing off the calendar. It tells you the truth about that specific slab.

What sealing doesn't do

Sealing helps granite resist stains, it doesn't make the stone stainproof. A glass of wine or olive oil left sitting overnight can still leave a mark even on a freshly sealed counter, so wipe up spills when they happen rather than letting them sit.

Sealing also has nothing to do with scratch resistance or heat. Granite handles a hot pan better than a lot of surfaces, but we still tell every customer to use a trivet. It resists scratching well too, but a cutting board keeps both your knives and the finish in good shape for the long run.

If you're not sure where your countertops stand, bring the question by. We're at 2015 Charleston Hwy in Cayce, and we're happy to look at a slab and tell you straight whether it needs attention.