Natural stone is harder than ceramic tile and far more expensive to replace, so the technique is worth learning before you drill.
Use a diamond core bit, not a masonry bit
A carbide masonry bit will scratch and chip polished stone. A diamond core bit cuts a clean hole. Buy the size specified for your screws or anchors, and buy two; they wear out.
Keep it wet and slow
- Locate studs behind the stone. If the stone is set on a mortar bed you may need a deep-scan stud finder or reference measurements from an adjoining wall.
- Mark holes on painter's tape. Start the bit at an angle to create a groove, then bring it upright once it has bitten.
- Drill at low speed with steady light pressure while a helper mists the hole with water. Stone dust turned to paste is a sign it's working; smoke or a burning smell means too fast or too dry.
- Once through the stone, switch to a wood bit for the stud pilot hole or the correct bit for your anchor.
- Seal each hole with clear silicone before mounting.
Where the load goes
Stone is brittle in tension. The screws must go into studs or a rated anchor behind the stone; the stone itself should not carry the load. Snug the flange screws so the flange sits flat on the stone without crushing it.
When to hire it out
If the stone is a large slab, book-matched, or in a shower you can't easily rebuild, a tile setter or stone fabricator can drill and mount in under an hour. The bar costs less than one cracked slab.
Questions about your bathroom? Call LiveWell at (440) 499-7221 or email info@livewellhs.com. We ship grab bars from Ohio to homes, contractors, and senior living communities nationwide.