How To Grout Shower Tile?
QUICK ANSWER
Grout shower tile with sanded grout for joints over 1/8 inch wide or unsanded for narrower joints. Press grout into joints with a rubber float held at 45 degrees, wipe excess with a damp sponge after 15 minutes, and seal the grout after a 7-day cure.
Grouting shower tile follows the same basic process as floor tile but has stricter requirements because the joints face constant moisture. The grout type, application technique, and post-install sealing all matter more in a shower than they do on a kitchen floor. Here is the right approach to grouting a shower so the joints stay watertight and mold-resistant for years.
What grout do you use in a shower?
For most shower tile, use sanded grout for joints 1/8 inch or wider and unsanded grout for narrower joints (down to 1/16 inch). Epoxy grout is the best choice for shower floors because it is truly waterproof and resists mold, but it is more expensive and harder to work with. Premixed urethane grouts (Mapei FlexColor, TEC Power Grout) bridge the gap, offering better water resistance than standard cement grout with easier installation than epoxy. Avoid any grout not rated for wet locations.
How is grouting shower tile different from floor tile?
The mechanics are the same (mix, apply diagonally with a rubber float, wipe excess, cure) but you are working at chest height instead of on the floor, which is slower and harder on your shoulders. The vertical joints also resist gravity less, so you need to push grout into them with more deliberate pressure. Cover smaller sections at a time (5 to 10 square feet instead of 10 to 20) since wall grout starts setting faster. Use change-of-plane sealant or silicone in corners and at edges, not grout, since grout cracks where surfaces flex against each other.
How do you keep the shower grout from cracking?
Use silicone or matching sealant in corners (where wall meets wall) and at all transition points (where wall meets floor, where tile meets tub). These joints flex slightly with use, and grout will eventually crack in those locations. The rest of the field (wall and floor joints) gets standard grout. Make sure the substrate behind the tile is rigid and properly waterproofed (cement board or a waterproofing membrane) before tiling, since flex in the substrate translates directly to grout cracking later.
How long before you can use the shower?
Wait at least 72 hours after grouting before any water exposure to let the grout reach initial cure. Wait 7 days before sealing (sealer cannot penetrate properly into still-curing grout) and another 24 hours after sealing before regular shower use. The grout itself reaches full strength at about 28 days. Many DIYers rush this step and the grout fails within months because it absorbed water before fully curing. Patience here saves the whole job.
Shower grouting works like floor grouting with stricter timing and product requirements. Use sanded grout for wider joints, unsanded for narrow ones, silicone in corners and at transitions. Wait 72 hours before water exposure, 7 days before sealing. Skipping the cure time is the most common reason DIY shower grout fails. Patience here is what makes the grout job last.
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