What size grout line for 24x48 tile?
Grout joint for 24x48 tile
1/8″minimum, large format
sanded grout — ANSI A108.02, at least 3× the tile's facial dimension variation
| Recommended joint | 1/8″ |
|---|---|
| Grout typejoints under 1/8″ take unsanded, 1/8″ and over take sanded | Sanded |
| ANSI absolute minimumno joint may be tighter than this, whatever the tile | 1/16″ |
| Large format?any side over 15″ counts, and it changes the mortar and the offset | Yes — 48″ side |
| Maximum running-bond offsetTCNA guidance for tiles with a side over 15″ unless the maker states otherwise | 33% |
| Mortarimproved polymer-modified, for back coverage across a large tile | ANSI A118.15 |
| — Joint by how the tile is made — | |
| Rectified porcelainedges ground square after firing — the tightest joints are only possible here — ANSI minimum 1/16″ | 1/8″ |
| Pressed (calibrated) porcelain or ceramicfired to size, so pieces differ slightly and the joint has to absorb it — ANSI minimum 1/8″ | 1/8″ |
| Natural stonecut to size but the material itself varies; honed stone is tighter than tumbled — ANSI minimum 1/8″ | 1/8″ |
| Handmade or hand-lookthe variation is the point of the tile, and the joint has to be generous — ANSI minimum 3/16″ | 3/16″ |
Notes
- 24x48. Large-format in both directions. Flatness of the substrate stops being a detail and becomes the whole job — the tile cannot bend to a floor that is out by a quarter inch.
- The rule is a multiple, not a number. ANSI A108.02 sets the joint at at least three times the actual variation in facial dimension of the tile you bought — with an absolute floor of 1/16″. That means the answer depends on the box in front of you, not on the size alone. Lay ten tiles face up, measure the smallest and the largest, and multiply the difference by three.
- This joint takes sanded grout. At 1/8″ and wider, unsanded grout shrinks and cracks as it cures. The sand is structural, not filler.
- Large format changes three things at once. Any side over 15 inches means: a higher-performance mortar (ANSI A118.15) to get back coverage across the tile, a substrate flat enough that the tile is not bridging a hollow, and an offset of no more than a third if you are running a bond pattern. A 50% offset on a 48-inch tile puts the crown of one tile against the edge of the next, and that lippage is visible from across the room under any raking light.
- Tighter joints are a design choice with a cost. A 1/16″ joint reads as a continuous surface and is what makes large-format tile look like slab. It also removes every bit of tolerance you had — the layout has to be right first time, the substrate has to be flat, and the tile has to be rectified. Going from 1/16″ to 1/8″ buys back a great deal of forgiveness for very little visual change.
- Manufacturer instructions override this page. Where the box specifies a minimum joint, that figure governs, and ignoring it is usually what voids the warranty.
24x48 tile
1/8″ minimum, with sanded grout.
The standard is a multiple, not a number
ANSI A108.02 sets the grout joint at at least three times the actual variation in facial dimension of the tile you bought, with an absolute floor of 1/16″.
That makes it a property of the box, not of the size. Lay ten tiles face up, measure the smallest and the largest, multiply the difference by three. Rectified porcelain will give you a very small number; a handmade tile will not.
Sanded or unsanded is decided by the joint, not the tile
Under 1/8″, unsanded. At 1/8″ and over, sanded. The sand is structural — unsanded grout in a wide joint shrinks and cracks as it cures, and sanded grout in a narrow one will not pack in properly and can scratch a polished glaze going in.
Tighter joints remove your tolerance
A 1/16″ joint is what makes large-format tile read as a continuous surface. It also means the layout has to be right the first time, the substrate has to be genuinely flat, and every tile has to be the same size. Going to 1/8″ buys back a lot of forgiveness for very little visual difference.
Nearby sizes
Read more
- Grout for 12 × 24 Tile: Why the Big Format Uses LessLarge format tile is the one place where the bigger product costs you less of something. Grout is that something, and the saving is exactly a quarter.
- What a 25 lb Bag of Grout Actually CoversA bag's coverage figure is real. It is also stated for one specific tile size, joint width and thickness — change any of the three and the number moves by a lot.
- Grout for Subway Tile: Three Times the 12-Inch FigureSubway tile is the highest grout consumption per square foot of any common format. If you sized the order from a floor tile figure, you are about a third of the way there.
- Sanded or Unsanded: The Joint Width That Decides ItThe dividing line is 1/8 inch and it is not a style guideline. Using the wrong one on either side of it produces a specific, predictable failure.