What Type of Grout for Shower: Complete Guide for Homeowners

Choosing the wrong grout is the single most common reason showers end up with cracked joints, black mold, and water damage behind the tile. Deciding what type of grout for shower walls and floors comes down to three factors: how wide your tile joints are, how much you want to fight mold, and your tolerance for maintenance. Get it right and your grout lines stay clean and watertight for 15 years; get it wrong and you’re regrouting in three.

Part of our Bathroom Remodeling & Flooring guide — explore the full guide →

The Three Main Grout Types

Modern tile grout falls into three categories, each with a clear best use:

• Unsanded (non-sanded) grout: Smooth cement-based grout for narrow joints under 1/8 inch. Ideal for shower walls and polished or glass tile that sand would scratch.
• Sanded grout: Cement grout with sand added for strength in wider joints, 1/8 inch and up. Standard for shower floors and most floor tile.
• Epoxy grout: A resin-based grout that’s nearly waterproof, stain-proof, and mold-resistant. The premium choice for wet areas.

Cement-based grouts (sanded and unsanded) are porous and must be sealed; epoxy is non-porous and never needs sealing. That single difference drives most of the decision.

Why Epoxy Grout Wins in Showers

If budget allows, epoxy grout is the best technical choice for a shower. Because it’s made from epoxy resins and a hardener rather than cement, it doesn’t absorb water, resists mold and mildew, and shrugs off the soap, shampoo, and cleaning chemicals that stain cement grout. You never have to reseal it.

The trade-offs are cost and difficulty. Epoxy runs roughly two to three times the price of cement grout and sets fast, making it harder to work with, so many DIYers hire a pro for an epoxy job. For high-use showers and shower floors that sit in standing water, that premium pays off in years of low maintenance.

Matching Grout to Joint Width

Joint width is the deciding factor between sanded and unsanded cement grout. For joints narrower than 1/8 inch, common on shower walls with tightly set subway or mosaic tile, use unsanded grout, which packs into thin lines smoothly without slumping. For joints 1/8 inch or wider, use sanded grout, because unsanded grout shrinks and cracks in wide gaps.

Shower floors almost always use sanded grout because the small mosaic tiles still leave joints in the sanded range, and the added sand gives the high-traffic, wet floor extra strength. One caution: sand can scratch polished marble, glass, or metal tile, so on those delicate surfaces use unsanded or epoxy even in wider joints.

Walls vs. Floors: Different Demands

A shower has two very different environments. The walls see splashing and steam but drain quickly, so sealed unsanded cement grout performs fine with regular maintenance. The floor, however, sits in pooling water, foot traffic, and constant moisture, the harshest spot in the whole bathroom.

That’s why many pros recommend epoxy at minimum on the shower floor and curb, even if you use cement grout on the walls to save money. The floor is where leaks and mold start, so it’s the smartest place to spend on the better product.

Sealing Cement Grout (and Why Epoxy Skips It)

If you go with cement-based grout, sealing is mandatory, not optional. After the grout cures (typically 48 to 72 hours), apply a quality penetrating sealer, and reapply it every year or two. Unsealed cement grout in a shower absorbs water, breeds mold, and breaks down fast.

Epoxy grout’s big advantage is that it’s already non-porous, so there’s nothing to seal, ever. That eliminates the yearly maintenance task most homeowners forget anyway, which is a major reason it lasts so much longer in wet areas.

Installation and Maintenance Tips

Whatever you choose, a few practices extend grout life. Use the correct trowel and fully pack the joints, voids are where water gets in. After grouting, give cement grout the full cure time before exposing it to water. Once installed, squeegee the walls after showering and run the exhaust fan to cut down on the moisture that feeds mold.

For cleaning, skip acidic and harsh cleaners on cement grout that erode it over time; a soft brush and a pH-neutral or oxygen-based cleaner keeps lines bright without damaging the joint or sealer.

Grout Color and Design Considerations

Grout color shapes the entire look of a tiled shower, and it’s a practical decision as much as an aesthetic one. Light grout (white, ivory) looks crisp but shows every speck of soap scum and mildew, demanding more upkeep. Mid-tone grays and greiges hide grime far better and are the smart choice for shower floors and high-use walls.

Matching the grout to the tile creates a seamless, expansive look that makes a small shower feel larger, while a contrasting grout emphasizes the tile pattern, ideal for showcasing a herringbone or geometric layout. One pro tip: with epoxy grout, the color is locked in and stays consistent because it doesn’t absorb dirt or fade, another reason it’s favored in wet, high-visibility areas.

Regrouting and Repair Down the Road

Even good grout eventually shows wear, and knowing when to repair versus replace saves money. Surface cracks, small missing chunks, and discoloration in cement grout can often be fixed by scraping out the damaged section with a grout saw and applying fresh grout. If cracking is widespread or the grout is crumbling, a full regrout is the better long-term fix.

Importantly, where tile meets the tub, the floor, or an inside corner, you should use flexible silicone caulk, not grout. These movement joints flex as the structure settles and as materials expand, and rigid grout in those spots cracks repeatedly. Many leaks blamed on “bad grout” are actually failed corner joints that should have been caulked. Keep a tube of matching silicone on hand and refresh those joints every few years.

Making Your Final Choice

For most homeowners deciding what type of grout for shower projects, the answer is: epoxy on the floor and high-moisture zones for its waterproof, no-seal performance, and either epoxy or sealed unsanded cement on the walls. Match cement grout to your joint width, sanded for wide, unsanded for narrow, and seal it religiously if you choose it. Spend a little more upfront on the wettest surfaces, and your shower will stay watertight and mold-free for the long haul.