Blog · Care
Sealing natural stone: the once-a-year routine that keeps it new
A surprising number of people choose engineered quartz over natural stone because they have heard that stone 'needs sealing', as if it were a second job. It is not. A penetrating sealer is a twenty-minute task once a year, and it is the only maintenance a granite or quartzite counter asks of you.
What a sealer actually does
Natural stone has microscopic pores. A penetrating sealer soaks into those pores and lines them with a water- and oil-repellent resin. It does not sit on top of the stone, does not change the finish and does not make the surface shiny. Its only job is to give you time: a sealed stone lets a spill sit on the surface for hours instead of drawing it in within minutes.
Which stones need it, and how often
Granite and quartzite: seal at installation and re-seal about once a year. Dense stones may go longer. Marble, limestone and travertine: seal more often, and remember that sealing protects against stains, not against etching from acids, which is a different problem.
Engineered quartz and porcelain: never. They are non-porous. Sealing them does nothing except leave a film you will have to wipe off.
The water test
To check whether a stone still has a working seal, put a few drops of water on a spot that gets used and wait ten minutes. If the water beads and wipes away leaving no darker patch, the seal is working. If the stone darkens under the drop, the water is getting in and it is time to re-seal.
How to seal in twenty minutes
Any good impregnating sealer from a hardware store will do; we can recommend the one we use. The process is the same for all of them.
- Clean the surface with a pH-neutral cleaner and let it dry completely.
- Apply the sealer with a cloth or foam brush, keeping the surface wet for the time on the label, usually five to fifteen minutes.
- Wipe off all the excess before it dries. Sealer left on the surface leaves a haze.
- Keep the counter dry for the cure time, typically a few hours.
What not to do
Do not use vinegar, lemon or bleach as a cleaner on any natural stone; they strip the sealer and, on marble, etch the polish. Do not buy a topical 'stone polish' that promises shine; it builds up and is hard to remove. And do not over-seal: more coats do not add protection, they add haze.
