It depends on the grout. A rapid-setting cement grout such as MAPEI Ultracolor Plus FA can handle water after about 3 days, while a single-component grout such as Custom Fusion Pro needs 7 days before a shower is used. Most grouts can take light foot traffic much sooner, from a few hours to a day. Fully submerged tile, such as a pool or spa, needs longer still, often 14 days. Check the product data sheet, because the times are measured at about 70°F and 50% humidity and get longer in cold, damp rooms.
Still buying grout? The grout calculator works out how many pounds you need for your tile and joint size.
Grout dry times by product
| Grout (type) | Foot traffic | Shower / water exposure | Submerged |
|---|---|---|---|
| MAPEI Ultracolor Plus FA (rapid-setting cement) | After 3 hours | 3 days | 3 days (72 h for pools and spas) |
| Custom Prism (cement) | 4 hours | Intermittent water after 3 days | 14 days |
| Custom Polyblend Plus (cement) | 16 hours | Not stated for showers | 14 days |
| LATICRETE PERMACOLOR Select (cement) | Heavy traffic 6 hours | Not stated | 14 days |
| Custom Fusion Pro (single-component) | 24 hours | 7 days | Not for submerged use |
| LATICRETE SPECTRALOCK PRO Premium (epoxy) | Light traffic 12 hours | Cleaners after 7 days | 10 days |
Where a data sheet gives no shower time, the safest choice is to wait at least as long as similar products (about 3 days for cement grout) and longer in cool weather, or ask the manufacturer.
Why grout needs time before water
Cement grout hardens by curing, a chemical reaction that continues for days after the joints feel hard. Water on grout that has not cured yet can weaken the surface and affect its color. Epoxy grout cures by a different reaction but also needs time before cleaners and water; LATICRETE lists full cure for its epoxy at 14 days at 70°F, 28 days at 40°F and 7 days at 95°F.
What slows grout curing
- Cool rooms: MAPEI says to extend curing below 60°F, and most grouts should not be installed below 50°F.
- High humidity: above about 70% relative humidity, curing slows (MAPEI).
- Poor ventilation in a closed bathroom: leave the door open and run the fan if you can.
Should you seal grout, and when?
Many modern grouts do not need sealing: MAPEI Ultracolor Plus FA, Custom Prism and Fusion Pro say sealing is not required, and LATICRETE says PERMACOLOR Select never needs it. If you do seal, wait for the grout to cure first: at least 48 hours for Prism and 72 hours at 70°F for PERMACOLOR Select. Older or standard sanded grouts are often sealed; follow the sealer label.
Before you shower: a checklist
- The cure time on your grout’s data sheet has passed, with extra days if the room was cold.
- Caulk at the tub, corners and changes of plane has also cured, per its label.
- Any sealer has dried for the time on its label.
- The first few showers are short, and the bathroom is ventilated afterwards.
Frequently asked questions
Can I shower 24 hours after grouting?
Only if your grout’s data sheet says so. For the products above, the shortest time before water exposure is 3 days.
How long before I can walk on grouted floor tile?
From about 3 to 24 hours depending on the product, as in the table. Keep it to light traffic for the first day.
And how long before grouting after setting the tile?
That depends on the thin-set; see how long thinset takes to dry before grouting.
Sources
- MAPEI Ultracolor Plus FA technical data sheet (2019, dealer copy) (foot traffic, curing and immersion times)
- Custom Building Products Prism grout data sheet (walkable, water exposure and sealing times)
- Custom Building Products Polyblend Plus grout data sheet (traffic and submersion times)
- LATICRETE PERMACOLOR Select data sheet (DS-281) (traffic, submersion and sealing times)
- Custom Building Products Fusion Pro grout data sheet (light traffic and shower exposure times)
- LATICRETE SPECTRALOCK PRO Premium epoxy grout data sheet (DS-681) (traffic and cure times at 40, 70 and 95°F)
