How to drill into a grout line without cracking the tile
Yes, you can drill into the grout between tiles, and the joint is deliberately the easy way in: it takes much less effort than the tile face, and a hole in grout is far easier to cover up later, which is exactly why Bosch's own DIY guidance steers joint drilling as the low-effort route for small fixings [1]. The dissenting camp is real and worth knowing before you start: grout is not as stable or strong as tile, so drilling into it is not recommended for anything that matters [7], and one newspaper how-to columnist tells towel-rail readers to place holes in the middle of tiles rather than on a grout line at all [18]. This page settles that argument by load, tabulates the bit and speed recommendations the big content sites contradict each other on, matches joint width to anchor size, and draws the hard safety line at grab bars. For the tile face itself rather than the joint, the companion page is how to drill into tile without cracking it.
What is actually in that line: three grouts, three targets
Grout is either a cement paste or an epoxy resin, and the difference decides how the joint drills [6] [9]. Within cement grout, the sanded or unsanded choice follows the joint width, not the installer's taste: joints 1/8 in and wider get sanded grout because the sand stops the joint shrinking and cracking as it cures, and narrower joints get unsanded because sanded grit will not pack into a tight line and can scratch polished tile faces [11] [10].
| Grout type | Joint width it lives in | How it drills | Sources |
|---|---|---|---|
| Unsanded cement | 1/16 to 1/8 in, polished tile and tight wall joints | The softest target: fine cement paste with no aggregate, easiest to drill, but the joint is too narrow for most plugs | [6] [9] [11] |
| Sanded cement | 1/8 to 1/2 in, floors and wide wall joints | Still easy to drill; the silica sand is abrasive and dulls bits faster, and the wider joint is the only one that fits real anchors | [6] [10] [11] |
| Epoxy | Any width, wet areas and kitchens | Much harder: resin plus hardener, with compressive strength above 5,000 psi against roughly 1,500 to 3,000 psi for Portland cement grouts, and installers report it is the most challenging to drill | [9] [10] [6] |
| Freshly grouted joint, any type | Any width | Not yet: cement grout needs about 72 hours before it handles water and traffic, and makers advise a full week before treating it as cured; drilling a young joint crumbles it | [14] [10] |
Cured age matters as much as type. Cement grout keeps gaining strength for weeks as hydration continues, and the surface that feels dry in hours is nowhere near finished [14]. A regrouted shower wall is the classic trap: the new line looks and feels done, and an anchor set into it in the first days holds nothing like it will a month later [14] [6].
The bit question: carbide or diamond, and who contradicts whom
This is where the grout articles that rank today fall apart, and the disagreement is the most useful thing about them. The same site will recommend different bits in its summary table and its step-by-step body. Tabulated, with each camp's corroboration:
| Source | Bit it names | Speed it gives | Also in this camp | Sources |
|---|---|---|---|---|
| shuntool summary table (drilling into grout between tiles) | Diamond drill bit | 500 to 1,000 RPM, described as low speed | toolsadvisers calls diamond the best grout bit overall | [2] [6] |
| shuntool body text, same article | Carbide-tipped masonry bit | Begin drilling slowly, avoid high speed | Bosch DIY says use a masonry bit from the start in joints; shuntool's own screw-hole article agrees | [2] [1] [4] |
| shuntool, can you drill into grout | Tile and grout bit, 1/8 in by 2 in | Variable, up to 2,500 RPM | moviecultists' carbide-for-ceramic camp points the same direction at far lower speed | [3] [7] |
| toolsadvisers | Diamond best, ceramic and carbide the cheaper pick | Low to moderate speed | The shuntool summary table's diamond row | [6] [2] |
| moviecultists | Carbide for ceramic, diamond for porcelain and glass | 100 to 200 RPM, low and slow | Bosch DIY and HealthCraft's install sheet both say start slow in rotary mode | [7] [8] [1] [19] |
The reasoned recommendation. Separate what the joint is from what the tile is. Cement grout is soft, brittle, dusty material, far softer than the tile beside it [3] [6], and a carbide-tipped masonry bit in rotary mode cuts it without ceremony, which is why Bosch's joint guidance starts with a masonry bit and why every farm's actual step-by-step body text lands on the same bit its summary tables skip [1] [2] [4]. The diamond recommendations make sense in exactly two cases: your hole must also cross the tile glaze, where diamond and spear-point carbide tile bits are the established tools [12] [13], or the joint is epoxy grout, whose 5,000-plus psi cured hardness rewards grit that grinds rather than a tip that shovels [9] [6]. For how each bit family actually cuts, see drill bits by material; for the size runs, the masonry bit size chart.
Hammer mode: off in the joint
The hammer-drill question has a clean answer here because three independent sources give the same one. Bosch DIY's joint instructions say to switch the hammer or percussion function off before drilling the grout [1]; moviecultists states the mechanism flatly, that the rapid pounding will crack the tile in almost all cases [7]; and HealthCraft's towel bar installation sheet says do not use a hammer drill, full stop [19]. The percussion that chips concrete efficiently is exactly the impulse a glazed tile edge cannot take, and the joint puts your bit within millimeters of two of them [7] [1].
Brick-joint divergence, disclosed. The sibling question, drilling into the mortar between bricks, is where hammer function reappears: shuntool's brick article lists a drill with a hammer function among its supporting tools for mortar joints [5], and its hardware logic is sound because brick mortar is a load-bearing structural bed, often in solid masonry. Tile grout is the opposite case: a thin filled decorative joint over a soft substrate, so the no-hammer rule holds [1] [19]. If your drill passes through the wall assembly into real concrete or block behind, that is a new hole in a new material: change to the masonry regime, which Bosch's tile guidance describes as continuing with a concrete or masonry bit in the wall behind the ceramic [12] [1]. What hammer action actually is, mechanically, is covered in hammer drill vs regular drill.
Speed: three camps, disclosed
The RPM numbers scattered across the ranking articles cannot be reconciled, only reported. moviecultists says low and slow, between 100 and 200 RPM [8]. shuntool's summary table says 500 to 1,000 RPM while calling that low speed [2], and shuntool's general grout article allows a variable drill up to 2,500 RPM [3]. toolsadvisers commits only to low to moderate [6]. What every camp shares, and what the manufacturer guidance confirms, is the shape of the instruction: start slow, let the bit carve, increase only once you are cutting cleanly, and never lean on speed in a brittle joint [1] [2] [4]. Practically: begin at the bottom of your drill's range, and if the grout is smoking or the bit is skating, you are too fast, whichever camp's number you started from. For speed targets in every other material, the drill speed chart.
Joint width versus anchor size
The hard geometric rule comes from Bosch: only holes and wall plugs smaller than the joint itself are suitable, and you cannot attach heavy cabinets this way [1]. Everything else follows from the width your wall actually has, and tile industry guidance sets those widths: tight wall joints run 1/16 to 1/8 in, floors run wider, and large-format rectified tile is installed with 1/8 in minimum joints, 3/16 in or more when non-rectified [15] [11].
| Joint width | Where you see it | What the joint can take | Sources |
|---|---|---|---|
| 1/16 in | Tight unsanded wall joints, mosaics | No plug fits; useful only for a probe hole or a screw threading into wood behind | [1] [15] [11] |
| 1/8 in | Standard subway tile, rectified large format | Still narrower than the 1/4 in holes towel bar anchors want; a wall anchor is possible only in the smallest sizes, so treat as screw-to-stud or change target | [1] [8] [15] |
| 3/16 in | Non-rectified large format, rustic wall tile | The boundary case: the smallest expansion plugs approach this width, and anything wider than the joint cracks its edges going in | [1] [8] [15] |
| 1/4 in | Floors, wide wall joints | The working width: the tile anchors shipped with towel bars are set in 1/4 in (6 mm) holes, which a 1/4 in joint admits | [16] [17] [1] |
| Wider than 1/4 in | Quarry and handmade tile | Comfortable anchor clearance; seal the ring gap around the plug with caulk so water cannot sit in the joint | [17] [19] [23] |
| Joint narrower than your anchor | Any tight wall | Fall back: drill the tile face with the proper tile bit, or move the fixing to the stud line behind the tile | [1] [18] [7] |
For the anchor-to-hole pairs themselves (plastic sleeves, mollies, toggles and the bits they need), see wall anchor sizes; for the masonry side, concrete anchor bit sizes by fastener. Depth is the quieter limit: the joint runs only as deep as the tile is thick, and installers are told to leave at least two thirds of the tile depth for grout, so a wall joint is a shallow target and one article caps joint drilling at about 1 in [24] [2].
How well does anything hold: grout versus tile versus stud
| Target | Holding reality | Right load for it | Sources |
|---|---|---|---|
| Grout joint | The weakest of the three: not as stable or strong as tile, easy to drill and easy to crumble, and the plug has almost no material to expand against | Light accessories: soap dishes, small fixtures, towel bars in cured wide joints | [7] [1] [8] |
| Tile face | Harder to drill and riskier for the glaze, but cured tile with the proper bit holds an expansion anchor better than the joint does | Medium loads when the joint is too narrow; the mid-tile school's default for towel rails | [18] [12] [13] |
| Stud or blocking | The only target with real numbers behind it: grab bar makers require wood studs (some all flanges, some 2 of 3 screws), rate 300 to 500 lb conditional on that mounting, and codes call for 250 lb in any direction | Everything heavy, and every grab bar, full stop | [20] [19] [21] |
Towel bars. The shipped-hardware reality: manufacturers' own sheets mount towel bars with anchors in 1/4 in pilot holes (Moen's Brantford line) or dedicated tile anchors set with a set screw (Ginger's), and a working builder's test is that the anchor should sit snug enough that it takes hammer taps to seat [16] [17] [18]. A towel bar loaded with wet towels is fine on that hardware in a sound, cured joint; the same column admits distrust of plastic anchors, which is the right instinct the moment the load grows [18].
Grab bars: the safety line. A grab bar is not a towel bar with a person on it, and the manufacturers' language is unambiguous. Newport Brass requires all mounting flanges into wood wall studs and rates its bar 350 lb only when properly installed, for assistance only, never total body weight [20]. HealthCraft rates 500 lb explicitly conditional on fastening into structural wood and says do not install into metal studs [19]. Federal accessibility guidance expects grab bar reinforcing to withstand a 250 lb load applied in any direction at any point [21]. Specialty anchor systems for no-stud grab bar mounting exist and are engineered for it, but they are 1-1/4 in hole hardware fastened through the wall assembly, not a plug poked into a grout line [22] [19]. If a stud is not where the bar needs to be, open the wall and add blocking, or move the bar; there is no grout-line shortcut for a safety grab [20] [22].
Finding the stud behind full-height tile: electronic finders often fail there, but studs run about 16 in on center, and a columnist's trick is to drill a small probe hole in the grout line near the top of the wall where a patch will not show, then fill any miss with matching grout or tub and tile caulk [23]. That is the one job where drilling grout is not about holding anything: the line is just the removable cover on the wall [23] [1].
Technique, step by step
- Mark the center of the joint, on tape. Masking or painter's tape over the line gives the bit something to bite and stops it skating onto the tile edge; the tape-mark step appears in every camp's method [4] [2] [19].
- Rotary only, lowest speed to start. Hammer off, clutch on a drill setting, speed at the bottom of the range, increasing only once the bit is cutting [1] [8] [4].
- Pilot, then step up. Start with a small bit (1/8 in is the size the articles name) and enlarge in steps to the anchor's hole size; the pilot guides the larger bit and prevents cracking [4] [2] [3].
- Control depth with a tape flag. The joint is shallow, roughly the tile's thickness with grout filling at least two thirds of it, so wrap a strip of tape around the bit as a depth stop [24] [2].
- Keep it cool and damp. A spray of water on the joint cuts dust and heat; both the diamond and carbide camps call for it [2] [6].
- Respect the dust. Grout dust is silica-rich and hazardous to inhale; wear a mask and goggles, a point both the farms and the silica literature make [6] [2].
- Check what is behind before you commit. Bathroom walls carry pipes and cables; the guides repeat the caution, and a scan plus a careful pilot is cheaper than a repair [6] [23].
- Seal and repair. In showers, sealant around the mounted fixture's wall contact keeps water out of the holes; abandoned holes fill with matching grout or tub and tile caulk [19] [23].
Grout line or tile face: picking the target
The two camps, honestly stated. The joint camp: Bosch DIY's position is that drilling the joint instead of the tile takes much less effort, that the holes are easily covered later, and that plugs smaller than the joint are legitimate for small fixings [1]. The tile-face camp: the Mercury News columnist positioning towel rail holes in the middle of tiles, away from grout lines, because the tile is the stronger material [18], with moviecultists supplying the reason grout gets the warning, that it is simply not as stable and strong as tile [7]. The reconciliation is that both are right about their own half of the problem: for a light load in a wide, cured joint, the grout line is the easier, patchable, lower-risk hole [1] [8]; for a heavier load, a narrow joint, or fresh grout under a week old, the tile face with a proper tile bit, or the stud behind everything, is the better target [18] [14]. The tile-face method, bits, speeds and water setup live on the tile drilling page.
Quick answers
- Can I drill into grout? Yes: it is the softest spot on the wall, with real limits on width, cure age, and load [1] [7].
- Which bit? Carbide masonry in rotary mode for cement grout; diamond if you are crossing tile glaze or the joint is epoxy [1] [2] [6].
- Hammer drill? Off, in the joint; rotary only until you are into real masonry behind the wall [1] [7] [19].
- What speed? The sites disagree from 100 to 2,500 RPM; everyone agrees start at the bottom of the range and never race a brittle joint [8] [2] [3].
- Will an anchor hold? For towel bars and light accessories in a cured 1/4 in class joint, yes; for heavy loads and grab bars, only the stud or blocking counts [16] [20] [21].
Related
For the tile face rather than the joint: how to drill into tile without cracking it. For bit families and how they cut: drill bits by material; for size runs, the masonry bit size chart. For percussion mechanics and when hammer mode earns its keep: hammer drill vs regular drill. For anchor-to-hole pairs in hollow walls: wall anchor sizes; for masonry fasteners: concrete anchor bit sizes by fastener. For RPM targets elsewhere: the drill speed chart.
Sources
- Bosch DIY, How to drill into tiles (joints section): drilling through tile joints instead of the tiles takes much less effort and holes are easily covered later, but only holes and wall plugs smaller than the joint are suitable and heavy cabinets cannot be attached this way; use a masonry drill bit from the start, use a centre punch first to prevent damage to surrounding tiles, switch off the hammer or percussion function, apply a little force through the grout then more once into the masonry (bosch-diy.com/gb/en/all-about-diy/drilling-tiles)
- shuntool, Drilling into Grout Between Tiles: summary table specifying diamond drill bit, 500 to 1,000 RPM recommended speed, up to 1 in depth, low risk to tiles; body text instead recommending a carbide-tipped masonry bit, masking tape over the mark, water spray to reduce dust and heat, drilling slowly with light pressure, and a small pilot hole before a larger bit to prevent cracking; a later FAQ in the same article stating a hammer function is not necessary and could damage tiles (shuntool.com/article/can-you-drill-into-grout-between-tiles)
- shuntool, Exploring the Possibility: Can You Drill into Grout: table specifying a tile and grout bit of 1/8 in diameter and 2 in length at variable speed up to 2,500 RPM; text noting grout hardens over time and is not as hard as the tiles around it, making it more susceptible to damage during drilling (shuntool.com/article/can-you-drill-into-grout)
- shuntool, Tips for Safely Drilling a Screw Hole into Tile Grout Without Cracking: masonry drill bit matched to the screw size, low speed setting, small pilot hole first then gradually increasing bit size, light steady pressure, masking tape applied, no hammering, backer board or scrap wood support (shuntool.com/article/how-drill-a-screw-hole-into-tile-grout-without-cracking)
- shuntool, Drilling into Grout Between Bricks: carbide-tipped masonry bit recommended for brick and grout; supporting tools listed include a drill with a hammer function, depth guide, and grout removal tool; steady pressure and slow controlled movements (shuntool.com/article/can-you-drill-into-grout-between-bricks)
- toolsadvisers, Can You Drill into Grout: sanded grout for gaps greater than 1/8 in, unsanded for smaller, epoxy a premium durable option; epoxy-based grout the most challenging to drill while cement-based is relatively easy; diamond-tipped bits called the best choice, ceramic bits the more affordable option; low to moderate speed; silica-rich dust hazardous to inhale; check for electrical wiring before drilling (toolsadvisers.com/can-you-drill-into-grout)
- moviecultists, Should I drill into tile or grout: grout is not as stable and strong as tile and drilling into grout is not recommended; ceramic tile drills with a carbide bit while glass and porcelain call for diamond-tipped; hammer drill setting will crack tile in almost all cases (moviecultists.com/should-i-drill-into-tile-or-grout)
- moviecultists, Do I mix grout by hand or drill: use a wall anchor when drilling through grout; low and slow is best for drilling into tile and grout, set the drill between 100 and 200 RPM; sanded grout best for 1/8 to 1/2 in lines (moviecultists.com/do-i-mix-grout-by-hand-or-drill)
- National Tile Authority, Tile Grout Types and Selection: unsanded Portland cement grout formulated for joints narrower than 1/8 in; sanded achieves stability through aggregate interlock; epoxy grout a two- or three-part resin system whose cured compressive strength exceeds 5,000 psi against 1,500 to 3,000 psi typical for Portland cement grouts (nationaltileauthority.com/tile-grout-types-and-selection.html)
- CeramicInfoSpot, Grouting Ceramic Tile step-by-step: unsanded for 1/16 to 1/8 in joints, sanded with 0.3 to 0.5 mm silica sand for 1/8 to 1/2 in joints; epoxy grout compressive strength 5,000 to 7,000 psi after full cure, 72 hours minimum before sealing, and significantly harder to work with than cement grout (ceramicinfospot.com/grouting-ceramic-tile-complete-step-by-step-guide)
- TileLines, How to choose tile grout: the joint-width rule decides sanded versus unsanded, 1/8 in and wider sanded up to about 1/2 in, narrower unsanded because sanded grit will not pack tight joints and can scratch marble and glass; epoxy is resin plus hardener, stain-proof, waterproof, never needs sealing (tilelines.com/blog/choosing-the-right-tile-grout.html)
- Bosch Professional, Bits for drilling tiles: tile drill bits must be used with the drill set to rotary; the HardCeramic bit is for tiles only and you change to a concrete or masonry drill bit for the masonry underneath; diamond dry and wet bits are the alternative for very hard ceramics (bosch-professional.com/gb/en/innovation/tile-drilling)
- RUBI, Choose the Right Tile Drill Bit: carbide-tipped masonry bits are the best choice for drilling glazed ceramic tiles and bathroom ceramics, good for shallow holes with experts preferring them for deeper ones; diamond-tipped bits drill glazed ceramics, porcelain, and glass, so no bit changes across tile materials (rubi.com/en/blog/tile-drill-bit)
- ScienceInsights, What Is Cement Grout: curing timeline of up to 72 hours before foot traffic or water exposure because hydration is still building the crystal structure that gives grout strength; most manufacturers advise a full 7 days before considering tile grout fully cured; strength continues developing over weeks (scienceinsights.org/what-is-cement-grout-uses-types-and-curing)
- DIYTileGuy, How Big Should Your Grout Lines Be: 1/16 versus 1/8 in joint guidance; per ANSI standards large-format tile in offset patterns needs a 1/8 in minimum joint for rectified tile and 3/16 in for non-rectified, with wider joints where tile size variation grows; the industry formula for minimum joint size (diytileguy.com/grout-lines)
- Moen (Creative Specialties International), Brantford 18 and 24 in Towel Bar Technical Specification (PDF): drywall installation uses a 1/4 in drill bit pilot hole per post with wall anchors pressed in and tightened until resistance increases without overtightening; into a stud, use the wood screws only (Moen BA1395 spec sheet, images.thdstatic.com)
- Ginger Co, Towel Bar Installation Instructions (PDF): tile or solid wall installation drills 1/4 in (6 mm) at the marks, inserts the supplied tile anchor, taps in until threads are reached, and secures with the set screw; drywall uses the drywall anchor instead (Newport Brass / Ginger Co EN-3840 sheet, images.salsify.com)
- Mercury News, Ask an Expert: How to drill into tile (George Heaton): position towel rail ends so holes fall in the middle of tiles rather than onto a grout line; masking tape, punch a small indentation, new carbide masonry bit fairly fast with real pressure; plastic anchors should fit snugly enough to need hammer taps, usually OK for towels though the author distrusts them (mercurynews.com/2007/11/10/ask-an-expert-how-to-drill-into-tile-carefully)
- HealthCraft, Invisia Towel Bar DC154C Installation Instructions (PDF): carbide tip drill for ceramic, consider diamond tip for porcelain; variable speed drill on slow to start the hole; do not apply too much pressure; do not use a hammer drill; use tape or a wood guide to stop walking; sealant recommended around wall contact points in showers; 500 lb rating conditional upon suitable fasteners and supporting surface, must be fastened to structural wood, not into metal studs (hardwarehut.com PDF dc154c-instructions-invisia-towel-bar)
- Newport Brass (Brasstech), Grab Bar Installation Instructions (PDF): ALL mounting flanges of the grab bar must be installed into wood wall studs; rated for persons up to 350 lb when properly installed; grab bars are not designed to support total body weight, assistance only; never use if any looseness is noted (kbauthority.com hosted PDF 2040-3942)
- HUD User, Fair Housing Act Design Manual, Requirement 6 (Reinforced Walls for Grab Bars): bathroom wall reinforcing must provide secure anchorage so grab bars withstand a 250 pound load applied in any direction and at any point (huduser.gov/portal/publications/pdf/fairhousing/fairch6.pdf)
- GrabBars.com, Do Grab Bars Need to be Installed in Studs: studs provide the most secure anchoring and are the best choice when located appropriately; where studs are not available, anchors specifically designed for grab bar installation can distribute weight in drywall or tile, following manufacturer recommendations (grabbars.com/articles/do-grab-bars-need-to-be-installed-in-studs)
- Las Vegas Review-Journal (Mike Klimek), Grab bar should be solidly anchored to wall framing: over full-height tile a stud finder is useless but studs run 16 in on center, so measure from corners or transfer from the adjoining room; drill a small hole in the grout line near the top of the wall to probe for the stud and fill extra holes with matching grout or tub and tile caulk; 2 of 3 flange screws hit the stud, sink screws at least 1 in into the wood, No. 12 stainless preferred (reviewjournal.com/life/home-and-garden/grab-bar-should-be-solidly-anchored-to-wall-framing-2894487)
- MyMaven, Installing Grout: What Most People Get Wrong: tile joints need at least two thirds of the tile depth available for grout so the joint material can grab the tile sides, with thinset squeeze-out removed before grouting (mymaven.org/installing-grout-what-most-people-get-wrong-about-tile-projects-1lyz)