Turning the mat changes the answer more often than you would think
Mat count is the ceiling of the floor length over the mat length, times the ceiling of the floor width over the mat width. Because both are ceilings, rotating the mat can change the product, and when it does not change the product it usually changes the number of cuts.
On a 12 by 10 ft floor with 4 by 6 ft mats it comes out even at six either way. Running the 6 ft dimension along the 12 ft length gives two columns and three rows; two of those mats need trimming from 4 ft to 2 ft to finish the 10 ft width. Turning the mat gives three columns and two rows, and three mats need trimming. Same six mats, one fewer cut, and cutting rubber is the slow part of the day.
| Floor | 6 ft along the length | Turned 90 degrees | Better |
|---|---|---|---|
| 12 x 12 ft | 2 x 3 = 6, no cuts | 3 x 2 = 6, no cuts | either |
| 12 x 10 ft | 2 x 3 = 6, 2 cuts | 3 x 2 = 6, 3 cuts | 6 ft along the length |
| 10 x 10 ft | 2 x 3 = 6, 4 cuts | 3 x 2 = 6, 4 cuts | either |
| 14 x 12 ft | 3 x 3 = 9, 3 cuts | 4 x 2 = 8, 2 cuts | turned, by a whole mat |
That last row is the case worth checking every time: turning the mat saved a whole mat, which on a hundred-pound mat at real prices is not a rounding error.
The weight is the part that surprises people
A 4 by 6 ft mat at three quarters of an inch is 1.5 cubic feet of rubber. At around 90 pounds a cubic foot that is about 135 pounds of solid rubber, and most commercial mats come in lighter than that because they are filled or have a void pattern underneath — a hundred pounds is a fair working figure. Six of them is 600 pounds arriving on a trailer and going through a stall door one at a time, folded, by two people.
Spread over the floor that is 5 pounds per square foot, which is a real number for a floor over anything framed and is reported here for that reason. It is not compared against anything, because what a floor will carry is not a question arithmetic answers.
The base is what the mats actually rest on
Mats laid on soft or uneven ground move, curl at the edges and open gaps that fill with bedding. The usual answer is compacted screenings or stone dust levelled flat first. Four inches over a 120 sq ft floor is 40 cubic feet, which is 1.48 cubic yards, and at 100 pounds a cubic foot that is 2 tons of material.
Order more than the calculated figure. That number is the compacted volume in place, and material bought loose compacts by a noticeable fraction once it is rolled or tamped. The supplier will tell you what their screenings do; a common allowance is a fifth on top, but it is their number rather than one for this page.
Where this hands off
Bedding goes on top of the mats and that volume is a different calculation entirely — the stall bedding calculator works out the bales for a given depth and what topping up costs against stripping. If the floor under the mats is a slab rather than screenings, the concrete slab calculator handles the pour, and the gravel driveway calculator covers ordering crushed stone by the ton. For the waste coming back out, the manure storage pad calculator takes the daily volume and sizes somewhere to put it.
Questions people ask
How many stall mats for a 12 by 12 stall?
Six 4 by 6 ft mats, exactly, with no cutting at all. The floor is 144 sq ft and each mat is 24 sq ft, and 12 divides evenly by both 4 and 6, so it works out clean whichever way you turn them. That is why 12 by 12 is the size everything is quoted against. Move to 12 by 10 and it is still six mats but now two of them need trimming, and at 10 by 10 it is six mats and four cuts.
Does it matter which way round I lay them?
Sometimes it saves a whole mat, and often it saves cuts. Rotating the mat swaps which dimension gets rounded up, and because both are rounded up the totals can differ. On a 14 by 12 ft floor, 4 by 6 mats give nine one way and eight the other. The calculator works both orientations every time and picks the one with fewer mats, breaking a tie on fewer cuts, because cutting three-quarter-inch rubber is slow and hard on the hands.
How much does a stall mat weigh?
A 4 by 6 ft mat at three quarters of an inch is around a hundred pounds, and a full stall is six of them. Solid rubber at about 90 pounds a cubic foot would put that mat at 135 pounds, so anything lighter is filled or relieved underneath. Enter the figure from the listing you are buying from, because half-inch and inch-and-a-quarter mats scale straight with the thickness and the difference over six mats is substantial.
How much base do I need under the mats?
The depth is a field because it depends on what is underneath, and the volume follows from it: four inches over a 120 sq ft floor is 1.48 cubic yards, about 2 tons of screenings at 100 pounds a cubic foot. Buy more than that, because the figure is the compacted volume once it is in place and levelled. What depth is right, and whether the ground under it needs work first, is a question for whoever has built stalls on your soil.
Should I leave a gap at the walls?
The default is no gap, because a gap fills with bedding and dirt and then holds moisture against the wall. Most people cut tight. The field is there because some mat types are specified to be laid with a small expansion gap, and if yours are, the calculator takes it off both dimensions before laying anything out, which can change the count. Follow whatever the mat maker specifies rather than the default here.