Cement, urethane or epoxy grout: which should I choose?

The three types side by side

Cement grout

Cement grout is mixed with water on site. Sanded grout is used for wider joints, unsanded for very narrow ones. It is easy to spread and to clean off the tile, which is why it is still the most common choice.

The trade-off is that it is porous. Without a sealer it soaks up soap, body oils and hair dye, and in a shower it can darken and grow mildew in the lines. It also cures unevenly if the mix or the humidity varies, so a single color can dry in slightly different shades across one wall.

Urethane grout

Urethane grout comes premixed in a tub. It resists stains, does not need sealing and dries to an even color. It needs a careful cleanup, because any film left on the tile is hard to remove later, and it takes longer to cure before the shower can be used. It works well on walls and floors where you want a light grout color that stays light.

Epoxy grout

Epoxy grout is a two-part mix. Once cured it is the hardest and most stain-resistant of the three, and it does not absorb water. The catch is installation: it sets quickly, so the crew works in small sections and must clean the tile surface right away or it leaves a haze. I recommend it for shower floors, steam showers and any place that gets the most water.

Corners get silicone, not grout

Walls and floors move a little with temperature, humidity and the house settling. Grout is rigid, so in an inside corner it cracks. Wherever tile changes plane, meets a tub or meets another material, we use a flexible sealant, usually a silicone made for tile, color-matched to the grout. That includes:

• Inside corners of the shower walls.
• The joint between the shower walls and the floor or tub.
• Where tile meets the window, the vanity top or the ceiling.

Silicone is a maintenance item. Expect to cut it out and replace it every few years, sooner if it peels or turns dark.

Keeping grout clean

• Use a pH-neutral tile cleaner. Bleach and acidic cleaners wear down cement grout and its sealer.
• Squeegee or wipe the shower walls after use, so water does not sit in the lines.
• Run the fan during and after the shower.
• Reseal cement grout on the schedule the sealer maker gives.

Grout type is written into our estimate, so you know what you are getting. Have questions about your tile choice? Contact me.

Can I put epoxy grout over my old cement grout?

Not as a layer on top. The old grout has to be removed to a good depth first. If the tile is sound, regrouting is possible, but if the grout failed because of a leak, I would look for the cause before anything else.

Does sealing make cement grout waterproof?

No. Sealer slows down stains and soaking, but grout is not waterproof under any sealer. What keeps water out of the walls is the membrane behind the tile, not the grout.

Related questions

• Which tile works best in a bathroom?
• What goes behind shower tile, and why does it matter?
• How do I know if there is water damage under my bathroom floor?
• All bathroom guides

Codes and permit rules change, and each Bay Area city applies them a little differently. Treat this page as a starting point and confirm the requirements for your address before work begins. We do that as part of every written estimate.