Grout Sealers Stop Mineral Stains (Maybe)

This grout sealer stops stains before they start.

“Cleanliness is next to godliness!”

Seems like questionable theology to me. But my aunt believes it, so the white, powdery stuff on her floor grout was driving her crazy. She kept scrubbing it away and it kept coming back. Like Satan.

The Devil had nothing to do with it, though. The problem is called “efflorescence” and is caused when moisture leaves masonry. The moisture carries minerals to the surface, then evaporates, leaving salty deposits behind. This is common on basement walls, brick and tile grout—especially if the tile is on a concrete floor. That was my aunt’s situation. The soil under the slab provided a constant source of moisture. Efflorescence can be caused by moisture from above, too. Grout can soak up puddles left by wet boots, for example. Later, that moisture will return to the surface, bringing minerals with it.

efflorescence on groutIn cases like these, there’s no sure cure for efflorescence. But I’ve had good luck with grout sealer. Sealer slows down moisture movement, whether from above or below. In my aunt’s home, sealer stopped efflorescence completely. In my own home, sealer cut the problem drastically.

Home centers carry a variety of sealers. DON’T use a sealer that forms a coating over the grout. Instead, look for terms like “penetrating” or “breathable” on the label. And don’t buy the cheapest stuff—you have to pay more to get a better sealer. I typically spend about $25 for a quart of sealer.

— Gary Wentz, Senior Editor

Check out these tiling articles from The Family Handyman:
How to regrout tile

Tile tips from a tile expert

Install a ceramic tile floor

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