A tile floor that looks tired usually has tile in fine condition — it’s the grout that’s stained, cracked, or missing. Regrouting takes a weekend, costs $50-$150 in materials, and visually transforms the floor.

But three common mistakes turn this from a winning DIY into a regret-inducing mess. Avoid them and you’ll get a clean, pro-looking result.

Here’s the technique.

When to Regrout vs. When to Replace

Regrout if:

  • Tile is sound (not cracked or loose)
  • Grout is stained, discolored, or just looks tired
  • Grout is cracked but not extensively crumbled
  • You’re tired of the current grout color

Replace tile if:

  • Tiles are cracking
  • Tiles are loose (tap each tile — hollow sound = tile is debonded from the substrate)
  • Subfloor under tile is soft (wood rot from a long-running leak)
  • The tile pattern itself is dated and you want a different look

For aesthetic refresh of a sound tile floor: regrouting is dramatically cheaper than replacing.

Tools and Materials

  • Grout saw (manual: $15. Electric: $40-$80, much faster for large areas. The Dremel oscillating tool with a grout-removal blade is the pro choice.)
  • Rubber grout float
  • Bucket
  • Sponges (multiple)
  • Painter’s tape
  • Microfiber cloths
  • Knee pads
  • Dust mask + safety glasses (grout removal is dusty)
  • Shop vacuum

Grout:

  • Sanded grout for joints wider than 1/8 inch (most floors)
  • Unsanded grout for joints under 1/8 inch (some wall tile)
  • Pre-mixed urethane grout ($60+ per gallon) — easier for first-timers, no mixing, more flexible. Recommended.
  • Grout sealer (for cement-based grouts only — urethane grouts are pre-sealed)

For a typical bathroom: 5 lbs of grout covers about 50 square feet of standard 12×12 tile.

Step 1: Remove the Old Grout (THE LONG STEP)

Goal: Remove the top 2/3 of the existing grout depth without damaging the tile edges.

Manual grout saw method (small areas):

  1. Hold the saw at a slight angle.
  2. Drag along the grout line, applying steady pressure.
  3. Each pass removes a bit more. Don’t try to remove too deeply in one pass.
  4. Stop when you’ve removed grout to about 2/3 of the joint depth.

Power tool method (larger areas):

  1. Use the Dremel oscillating tool with a 1/16-inch grout removal blade.
  2. Set the speed to medium.
  3. Run along the grout line, keeping the blade between the tiles (don’t touch the tile edges).
  4. The grout disintegrates; vacuum as you go.

Critical: Don’t chip or crack the tile edges. The grout removal blade is meant to chew through grout — it’ll also eat tile if you let it slip onto the surface. Take your time.

For 100 square feet of floor with 1/8-inch grout lines: about 4-6 hours with a power tool, 8-12 hours by hand.

Step 2: Clean the Joints

After removal:

  1. Vacuum thoroughly to get all the dust out of the joints.
  2. Wipe the floor with a damp cloth to capture residual dust.
  3. Inspect — any remaining grout chunks should be picked out with a utility knife or screwdriver.
  4. Let the joints dry fully — at least 24 hours before applying new grout.

The new grout won’t bond to dust or moisture. This step matters more than people think.

Step 3: Apply the New Grout

Mix per label if using powder. Should be peanut-butter consistency — not soup, not solid.

Apply with the rubber float:

  1. Scoop a softball-sized blob onto the tile.
  2. Hold the float at 45 degrees to the tile surface.
  3. Press the grout INTO the joints, working diagonally to the joint direction.
  4. Make multiple passes from different angles to ensure the joints are fully filled.
  5. After about 5-10 minutes (or per label), use the float at a steeper angle to scrape excess grout off the tile surface.
  6. Don’t worry about residual film yet — that comes off with the sponge in step 4.

Work in 25-50 square foot sections at a time. Don’t try to do the whole floor before cleaning — the grout sets up too fast.

Step 4: Clean the Tile Surface

Critical timing — start before the grout fully cures.

  1. Wait the time on the label (typically 15-30 minutes) for grout to firm up.
  2. Wet a large sponge in clean water and squeeze most of the water out.
  3. Wipe the tile surface in a circular motion. Goal: remove the grout film without removing grout from the joints.
  4. Rinse the sponge frequently. A muddy sponge just smears the haze around.
  5. Multiple passes — each pass with a clean sponge removes more haze.
  6. After about 2-3 hours, a residual chalky haze is normal. Don’t try to remove it now — let the grout cure overnight.

Step 5: Final Haze Removal and Sealing

After 24-48 hours (per label):

  1. Buff the haze off with a dry microfiber cloth.
  2. For stubborn haze: a 50/50 white vinegar + water solution helps. Don’t use anything stronger or you’ll affect the grout.
  3. For cement grouts only: apply grout sealer per label. This is what makes the grout stain-resistant. Skip this step and the new grout will look just as stained as the old grout in 2 years.
  4. Urethane and epoxy grouts don’t need separate sealing — they’re already waterproof.

Common Mistakes

  • Removing grout too deep. Going to the full depth of the joint exposes the substrate underneath, which can lift tile or create a soft spot. Stop at 2/3 depth.
  • Chipping the tile edges with the grout saw. Once chipped, those edges show forever. Take your time.
  • Applying new grout over dust. Won’t bond. Vacuum thoroughly first.
  • Not waiting long enough between haze cleaning passes. Wiping too soon pulls grout out of the joints. Wait the recommended time.
  • Skipping the sealer on cement grout. New grout that isn’t sealed stains like the old grout did. Always seal cement-based grouts.
  • Walking on the floor too soon. Grout cures over 24-72 hours. Walking on it during cure pulls the grout below the tile surface, leaving low spots.

When to Hire It Out

  • Large areas (over 200 square feet) — the grout-removal labor becomes prohibitive
  • Severely damaged grout that may indicate water damage to the substrate
  • Stone tile (different grouting techniques and sealing requirements)
  • Decorative tile or mosaic patterns where precision matters

The Bottom Line

Regrouting is one of the highest-visual-impact maintenance projects in a house. A tired-looking tile floor becomes new again for $50-$150 in materials and a weekend of careful work. The technique is straightforward; the patience for grout removal is what separates good results from bad.

For the full sequence including grout color selection, the special techniques for shower walls, and the substrate-repair scenarios, see Regrout a Tile Floor.

For a tile floor that needs more than regrouting (loose tiles, water damage, planning a replacement), book a free 20-minute consultation.