How Much Thinset for 200 Square Feet of Tile?
Thinset, 50 lb bags
6
200 square feet of 12 by 24 tile, at the coverage a large notch trowel gives.
Anything 15 inches or longer counts as large format. The substrate has to be flat inside an eighth of an inch over ten feet, the notch goes up to half by half, and every tile gets back buttered for coverage. Offset the joints by a third at most, because a running bond half offset on a long plank telegraphs every bit of tile warp as lippage.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Area to tile200 sq ft
- Tile width12 in
- Tile length24 in
- Tile thickness0.375 in
- Grout joint0.125 in
- Tiles per box8 each
- Waste allowance10 %
Tiles needed109 tiles
Anything 15 inches or longer counts as large format. The substrate has to be flat inside an eighth of an inch over ten feet, the notch goes up to half by half, and every tile gets back buttered for coverage. Offset the joints by a third at most, because a running bond half offset on a long plank telegraphs every bit of tile warp as lippage.
| Area with 10% waste | 220 sq ft |
|---|---|
| Coverage of one tile | 2.031 sq fttile plus one joint |
| Tiles per square foot | 0.49 |
| Boxes at 8 per box | 14 |
| Thinset, 50 lb bags | 6about 40 sq ft per bag at this tile size |
| Grout | 10.1 lbsold in 10 and 25 lb boxes |
| Backer board, 3 by 5 sheets | 14 |
The material list this produces
| Tile, boxes | 14 |
|---|---|
| Thinset mortar, 50 lb bags | 6 |
| Grout, lb | 11 |
| Tile spacers, each | 218 |
| Cement backer board, 3 x 5 sheets | 14 |
| Backer board screws, each | 560 |
Waste allowance compared
Waste is the only input here you choose rather than measure, and it is the one that decides whether the job finishes on a Saturday or on the following Saturday.
| Waste allowance | Tiles needed | Boxes at 8 per box |
|---|---|---|
| 5% | 104 tiles | 13 |
| 10% | 109 tiles | 14 |
| 15% | 114 tiles | 15 |
| 20% | 119 tiles | 15 |
What else matters here
Six bags, and the reason is the trowel rather than the floor. Thinset coverage is a function of notch size and notch size grows with the tile, so the same 200 square feet that takes 4 bags under a 12 by 12 takes 6 under a 12 by 24.
The rough figures are 85 square feet a bag with a quarter by quarter square notch under small tile, 60 with a quarter by three eighths under a 12 inch tile, and 40 with a half by half under large format where you are also back buttering. Your bag prints its own coverage and that number governs.
Buy one bag more than the arithmetic. Thinset that has been open and has taken any moisture goes off, so the spare is only useful if it stays sealed, but running out at four in the afternoon with a third of a floor spread is worse than a wasted bag.
What this calculator assumes
- The tile count is worked out from the space one tile actually occupies, which is the tile plus one grout joint on two sides, not the tile on its own. On a 12 by 24 with an eighth inch joint that difference is about one percent, and on a mosaic it is far more.
- 10 percent waste suits a straight lay in a square room. A diagonal or herringbone lay wastes 15, and a room full of jogs, niches and closets can reach 20.
- Grout is figured geometrically: the joint volume is the space around each tile times the tile thickness, converted at 105 pounds per cubic foot, which is where sanded grout lands once mixed. Manufacturer coverage charts vary, so treat this as the order quantity and not the gospel.
- Thinset coverage follows the trowel, and the trowel follows the tile: about 85 sq ft from a 50 lb bag with a quarter inch notch under small tile, 60 under 12 inch, and 40 under large format where the notch grows and the tile gets back buttered.
Questions people ask
How many bags of thinset for 200 square feet?
About 6 at 50 pounds for a 12 by 24 tile, or 4 for a 12 by 12. The difference is the trowel, not the floor.
How much thinset does a bag cover?
It depends on the notch, and the notch follows the tile. A quarter by quarter square notch under small tile stretches a 50 pound bag across most of 85 square feet, a quarter by three eighths under a 12 inch tile gets about 60, and half by half under large format with back buttering is nearer 40. The bag states its own figure and that is the one that governs.
Do I need to back butter large format tile?
Yes, on anything with a side of 15 inches or more, and in practice on 12 by 24 as well. Notched thinset alone leaves voids under a big tile, and a void under the corner of a tile is where it cracks the first time something heavy lands on it.
The tile calculator takes any dimensions you like and hands back the same list.