Guide · 5 min read
How to Grout Tile: Timing, Technique and the Two-Sponge Method
Grout tile in four moves: mix small batches, pack joints diagonally, first wipe 10–20 min after packing, then buff haze. Plus when grout is cured.
Free calculator — runs in your browser, nothing is uploaded.
How to grout tile, step by step (the short version)
Wait for the thinset to cure (usually 24 hours), then work in areas you can finish inside the grout's working time. The whole sequence for a 50 sq ft floor takes a first-timer two to three hours, most of it cleaning.
- Remove spacers and clips, and vacuum the joints so they are open to full depth.
- Mix to a peanut-butter consistency, let it slake 5–10 minutes, remix — no more water after that.
- Pack the joints with a rubber float held at 45°, working diagonally across the joints.
- Scrape the excess off with the float edge held nearly upright, again diagonally.
- First wipe with a barely damp sponge 10–20 minutes later, when the grout is firm to a fingertip.
- Second wipe with a clean, wrung-out sponge to shape the joints; buff the haze with a dry cloth after an hour.
- Keep traffic and water off for 24–72 hours; seal cement grout only after it has cured (check the bag).
How much grout to buy
Grout fills the joints, so the amount depends on joint width, joint depth (the tile's thickness) and how many joints there are. Worked out from that geometry at 110 lb per cubic foot for sanded grout: 100 sq ft of 12x12 tile, 3/8 in thick, with 1/8 in joints takes about 7.1 lb. The same floor in 12x24 tile has fewer joints and takes about 5.3 lb. A 30 sq ft backsplash of 3x6 subway tile, 5/16 in thick, with 1/16 in joints takes about 2.4 lb of unsanded grout.
Buy the next bag size up rather than the exact weight: some grout always stays in the bucket and on the sponge, and a little left over in a sealed bag is what you will use to patch a joint later. The grout calculator runs the same geometry for your tile size, joint and area.
Grouting day essentials
QEP 70005Q-6D 7.5 Inch x 5.5 Inch x 1.875 Inch Grouting, Cleaning and Washing Sponge, X-Large, 6-Pack
$8.97
Check price on Amazon
QEP 70020-18 Epoxy Grout Sponge 7" x 5" x 2-1/2" Teal Color - Individually Bagged
$4.63
Check price on Amazon
POWERTEC Large Square Grout Sponge – Professional Tile Grout Removal Cleaning Sponge – Heavy-Duty Absorbent Sponges, Multi-Purpose Cleaning Tool for Floors, Kitchen, and Bathroom – 4PK (72106)
$17.19
Check price on Amazon
As an Amazon Associate I earn from qualifying purchases.
Prices as of Oct 10, 2026, 6:33 AM UTC. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Sanded, unsanded or epoxy?
Joint width decides most of it. Unsanded grout is for joints of 1/8 in or narrower and for polished stone or glass that sand could scratch. Sanded grout is for joints of 1/8 in and wider, where the sand stops the joint shrinking and cracking. Epoxy grout suits either width where stain resistance matters most, but it sets faster and is harder to clean off, so it is a poor first grouting project.
Whatever you choose, follow the joint-width range printed on the bag — that range overrides any rule of thumb. The full comparison is in sanded vs unsanded vs epoxy grout.
Mix less than you think
Grout has a working time of 30–60 minutes once mixed, and you can't re-temper it with water. Mix a batch you can spread in that window — for a first-timer, half a bag at a time is plenty.
Mix to a smooth paste, let it slake 5–10 minutes, remix without adding water, and go. Too-wet grout shrinks, cracks, and cures weak; it should hold a soft peak, not pour.
Pack the joints, don't paint them
Hold the float at 45 degrees and drive grout diagonally across the joints with real pressure — you're packing the joint full, not spreading grout on the surface. Then squeegee the excess off with the float nearly vertical, still working diagonally so the edge doesn't dig joints out.
Work in sections of maybe 20–40 sq ft: spread, pack, squeegee, then start washing before the grout firms up. On a big floor, that means grout-and-wash cycles, not grout everything then wash everything.
The two-bucket wash
The first wipe, 10–20 minutes after packing, shapes the joints. Use a damp — not wet — sponge in light circular passes, rinsing and wringing constantly. One bucket for the dirty rinse, one with clean water for the final pass. Over-watering is the #1 cause of washed-out, blotchy, weakened joints.
A dry haze will film over the tile as it cures. Buff it off with a microfiber cloth the next day. Haze left for weeks needs a specialty haze remover — buff early and it's effortless.
Cure vs dry, and the sealer window
Grout feels dry within hours but cures chemically over days. Keep heavy traffic off floors for 24–72 hours and water off shower grout for the time on the bag — often 3 days.
Seal cement grout after it cures (check the bag; 48–72 hours is typical). Sealing too early traps moisture and clouds the grout; sealing is skipped on epoxy entirely.
Choosing the tools? See our grout tools buying guide.
Do this math on the job site — in the free app
Smart Tile Calculator for Android: offline, in your pocket, free.
FAQ
Why is my grout blotchy or lighter than the sample?
Almost always too much wash water or wiping too early, which pulls pigment and cement out of the surface. Consistent damp-sponge technique keeps color even.
How long before I can walk on grouted tile?
Light foot traffic after 24 hours is typical; keep rugs and furniture off for 72 hours and don't wet-mop for several days. The bag's cure schedule overrides any rule of thumb.
Can I grout over old grout?
Only if you remove at least 2/3 of the old grout depth first — new grout needs depth to bond. A grout saw or oscillating tool makes that a dusty but doable afternoon job.
How long after laying tile can I grout?
Usually 24 hours for standard thinset or mastic, sooner for rapid-setting mortars. The time printed on the mortar bag is the one to follow. Grouting too early can shift tiles and trap moisture under the grout.
How much grout do I need for 100 square feet?
For 12x12 tile 3/8 in thick with 1/8 in joints, about 7.1 lb of sanded grout. Larger tiles need less because there are fewer joints; small tiles and wide joints need much more. The grout calculator works it out for your exact tile and joint size.
Keep reading
- Sanded vs Unsanded vs Epoxy Grout: Which One Do You Need?
Grout types explained by joint width and location: when sand scratches tile, why epoxy wins in showers, and how much of each type a bag actually covers.
- Grout Color: Match the Tile or Contrast It?
What matching vs contrasting grout does to a room, why white grout is a maintenance commitment, and how to test color before committing to 200 square feet.