Should You Seal Your Grout? What Sealing Does (and Doesn't Do)

Standard cement-based grout is porous, which is why it soaks up dirt and spills and slowly turns gray. A grout sealer fills those pores so liquids bead up instead of soaking in. Here's what you need to know before you buy a bottle.

What sealing does

• Slows down staining from spills, mopping water and soil.
• Makes regular cleaning easier.
• Helps grout keep its color longer.

What sealing doesn't do

• It doesn't clean grout — sealing dirty grout locks the dirt in.
• It doesn't make grout stain-proof; spills still need to be wiped up.
• It doesn't last forever. Most penetrating sealers need to be reapplied every year or two, depending on traffic and the product.

The water drop test

Put a few drops of water on a grout line. If the grout darkens and the water soaks in within a few minutes, it's unsealed or the sealer has worn off. If the water beads up, the sealer is still working.

Does every grout need sealing?

Not all of it. Epoxy grout is non-porous and doesn't need sealing. Most standard sanded and unsanded cement grouts benefit from it. Check with your installer or the grout manufacturer if you're unsure.

Clean first, then seal

Sealing only works on clean, completely dry grout. That's why the best time to seal is right after a deep cleaning — once the grout has fully dried. Follow the sealer's instructions for dry time before and after application, and keep the sealer off the tile faces if the label says to.

Keep it looking new

• Use a pH-neutral cleaner for everyday mopping.
• Change mop water often so you're not spreading dirty water into the lines.
• Dry the floor after mopping.
• Avoid acidic cleaners like vinegar on natural stone.

Grout that has gone gray or dark usually needs a professional clean before sealing will make any difference. Our tile and grout cleaning pre-treats the grout lines and uses hot water extraction to rinse out what mopping leaves behind. For DIY tips, see removing hard water stains.