Grout for large format tile
Large format tile, usually meaning any tile with a side 15" or longer, has far fewer joints per square foot than small tile. A 12×24" floor needs a fraction of the grout a mosaic does. Large rooms still add up, so it's worth calculating before you buy.
| Tile | Thickness | Joint | Sanded | Unsanded |
|---|---|---|---|---|
| 12×24" | 3/8" | 1/8" | 5.1 lbs | 4.2 lbs |
| 12×24" | 3/8" | 3/16" | 7.7 lbs | 6.3 lbs |
| 24×24" | 3/8" | 1/8" | 3.4 lbs | 2.8 lbs |
| 24×48" | 3/8" | 1/8" | 2.6 lbs | 2.1 lbs |
| 6×36" | 3/8" | 1/8" | 8.0 lbs | 6.5 lbs |
| 8×48" | 3/8" | 1/8" | 6.0 lbs | 4.9 lbs |
Choosing a joint width
Tile is never perfectly uniform, and the grout joint has to be wide enough to absorb the size differences between tiles. Installation standards call for a joint of at least 1/16", and wider when the tile varies more.
- Rectified tile has edges ground to a precise size after firing and is commonly set with joints around 1/8".
- Non-rectified (pressed-edge) tile varies more and usually needs 3/16" or wider.
- The tile manufacturer's recommended joint width, printed on the box or spec sheet, takes priority over general guidance.
Going from 1/8" to 3/16" joints increases grout by 50%, so settle on the joint width first.
Sanded or unsanded?
Most large format floors use joints of 1/8" or wider, which call for sanded grout. If your tile is polished or has a soft glaze, check that sanded grout won't scratch it by testing on a spare tile. See sanded vs. unsanded grout for more.
Wood-look plank tile
Plank tiles like 6×36" and 8×48" are long but narrow. Their long sides add up, so they use more grout per square foot than a square tile of the same area. Enter both dimensions in the calculator to account for this.