How to Remove Grout Without Chipping Tile: Tools, Depth and Epoxy

To remove grout, score down the center of each joint with a carbide grout saw or an oscillating multi-tool fitted with a carbide or diamond blade sized narrower than the joint, then work outward to the tile edges and clean them with a carbide scribe. Go at least two thirds deep. Avoid grinders unless you have experience; they remove grout fast but chip tile and cut membranes.

Before you start: measure the joint and know what is behind it

Two facts decide the tool and the technique: how wide the joint is and what lies under the tile. If you are not sure removal is even the right repair, check when regrouting won't work first. Measure several joints with a set of feeler gauges or a drill bit used as a gauge. Factory-edged wall tile is often set with 1/16 inch joints, mosaics commonly have joints around 1/16 to 1/8 inch, and floors run 1/8 to 3/8 inch. Rectified porcelain is often set tight, and joints that look 1/8 inch can measure 3/32 inch. See the joint width guide for typical ranges.

Then find out what is under the tile. In showers built with surface-applied sheet or liquid membranes, the waterproofing sits directly behind a thin layer of thinset, often just 1/8 inch or so beneath the back of the tile. A tool that plunges through the joint can cut the membrane and create a leak. Over plywood or backer board, an overly deep cut weakens the substrate. Over concrete there is less to damage, but deep cuts still waste effort and raise dust.

Also identify the grout type. Cement grout is gritty and scratches with a key. Epoxy grout looks slightly glossy or plastic-like, does not absorb water drops, and resists a key scratch. Urethane and premixed grouts feel somewhat plastic and may scratch with effort. Removal technique differs for epoxy, covered below.

Grout removal tools compared

For a broader look at hand and power tools, see grout tools.

Carbide hand saws

A hand grout saw has a short blade coated with tungsten carbide grit, in widths that commonly match 1/16 and 1/8 inch joints. They are slow but nearly foolproof: you feel the moment the blade touches tile and can correct before damage. Use short, firm strokes along the joint, letting the grit do the work. They are the right tool for a few joints, delicate glass or handmade tile, and finishing work near fixtures. Replace the blade when the grit wears smooth; a dull blade invites you to push harder, which is when slips happen.

Oscillating multi-tools

An oscillating tool moves its blade back and forth through a tiny arc thousands of times a minute. It cuts rather than spins, so it does not grab and run along the joint the way a rotary bit does. Grout blades come in carbide grit and diamond grit, in thicknesses usually around 1/16, 3/32 and 1/8 inch. Pick a blade at least slightly narrower than the joint. Start the cut in the center of the joint, hold the blade in line with it, and use light pressure at moderate speed. Most setters would choose this tool for a bathroom-sized regrout.

Rotary tools and grinders: the real risks

Small rotary tools with grout-removal bits are marketed for this job, and they work on wide, straight joints, but the spinning bit tends to climb out of the joint and skate across the tile edge. Use the depth guide attachment, keep speed moderate, and practice on a hidden area.

Angle grinders with a thin 4 or 4-1/2 inch diamond blade are how many professionals clear large floors. They are also the source of most removal damage:

• Overcuts at intersections. A round blade cannot cut the end of a joint square without either stopping short or nicking the crossing tile.
• Chipped and burned edges. A brief wobble takes a bite out of glaze or polished stone, and the chip is permanent.
• Membrane and substrate damage. A blade set too deep cuts through thinset into sheet membranes or backer board.
• Kickback. Blades can bind in joints and throw the tool.
• Dust. Grinders generate large volumes of respirable silica dust unless shrouded and vacuumed.

Dust and safety

Cement grout contains sand and portland cement, both sources of respirable crystalline silica. OSHA's silica rules for construction (29 CFR 1926.1153) list control methods for handheld power tools, generally a shroud with a dust collector or water delivery, plus respiratory protection in some conditions. For a homeowner that translates to:

• A dust shroud on any grinder, and a vacuum with a HEPA filter connected to it or held at the cut.
• A fitted N95 respirator at minimum, and an elastomeric half mask with P100 filters for power-tool removal.
• Safety glasses or goggles; grout chips fly.
• Hearing protection for grinders and multi-tools.
• Closing off the room and running an exhaust fan out, not a fan blowing dust through the house.

Avoid dry-sweeping the dust; vacuum it with the HEPA vacuum instead. Broader PPE guidance is in grout safety.

Step-by-step grout removal

1. Prepare the room. Cover the tub or floor with a drop cloth, tape plastic over cabinets and vents, plug the drain, and set up the vacuum and respirator before you start.
2. Remove caulk first. Cut out any sealant at corners, the tub line and fixtures with a utility knife, so it does not gum up your blades.
3. Select and test the blade. Choose a blade narrower than your narrowest joint. Make a test cut in an inconspicuous joint to check control and depth.
4. Score the center of each joint. Run the tool or hand saw straight down the middle of the joint along its full length. Do the long horizontal joints first on walls, then the vertical ones. Keep the blade upright and aligned with the joint.
5. Deepen in passes. Make several shallow passes rather than one deep one, until you reach at least two thirds of the joint depth or full depth for regrouting. Check depth with a nail or ruler.
6. Work the edges. Once the center is cut, the remaining grout along each tile edge is a thin strip. Break it away with a carbide scribe or a hand saw angled slightly toward the joint, never pried against the tile.
7. Finish intersections and corners by hand. Clear the last 1/2 inch at joint intersections, near fixtures, and in inside corners with a hand tool to avoid overcuts.
8. Clean the tile edges. Scrape both edges of every joint so bare tile body is exposed. Residue on edges is what weakens the bond of new grout.
9. Vacuum and inspect. Vacuum each joint thoroughly, then inspect with a flashlight held low across the surface. Look for chips, remaining grout and any damage to the substrate before you move on to regrouting.

Removing epoxy grout

Cured epoxy grout is much harder and tougher than cement grout. It is a thermoset resin filled with sand or other aggregate, and it bonds tenaciously to tile edges. Carbide hand saws barely scratch it, and carbide oscillating blades wear out quickly. The approach that works is heat plus cutting:

1. Heat a short section. A heat gun warms the epoxy until it softens. Many epoxy grout manufacturers suggest heat for removal in their data sheets. Move the gun constantly, work about a foot of joint at a time, and keep the heat off sealants, plastics and anything flammable.
2. Cut while warm. Use a diamond oscillating blade or a carbide scraper in the softened grout. Epoxy cuts and peels more readily warm than cold.
3. Scrape the edges. Remaining film on tile edges can often be shaved away with a razor scraper while warm.

Be careful with heat on glass tile, natural stone and some thin porcelain: rapid local heating can crack tile, and stone can discolor. Test first and keep the heat moderate. Chemical epoxy removers are sold mainly for removing epoxy haze from tile surfaces; they act slowly on a full joint and are usually a supplement, not a substitute, for mechanical removal. Read the remover's label for compatibility with your tile and stone.

Urethane and premixed grout

Single-component urethane and premixed grouts are softer than epoxy but have a rubbery quality that can gum up fine-grit blades. A carbide hand saw or carbide oscillating blade at lower speed works well. Clear the blade frequently. Some manufacturers publish specific removal advice, so check the original product's TDS if you know which product was used.

Natural stone, glass and handmade tile

• Polished marble and limestone: soft and easily chipped. Use hand tools, and tape the tile edges with painter's tape as a guard. Do not use acid products to soften grout on calcareous stone; acid etches the polish.
• Glass tile: chips easily and scratches. Hand tools or a carbide oscillating blade on low speed only.
• Handmade and zellige tile: irregular edges and wide, uneven joints. Expect slow hand work and accept that some edge glaze may flake; see grout for handmade and zellige tile.