Calculators/ Interior/Deck Mud Calculator
Deck Mud Calculator
Dry pack mortar for shower pans and tile beds.
Deck mud is a dry pack mortar: sand and cement mixed with barely enough water to hold a squeezed handful together. It is what shower pans and thick-bed tile floors are sloped with, because a wet mix would slump instead of holding the pitch you trowel into it.
How this is calculated
- Volume = area × average thickness ÷ 12. A shower pan is sloped, so use the average of the thickness at the drain and at the perimeter.
- A 60 lb bag of pre-mixed deck mud yields roughly half a cubic foot.
- Mixing your own is 5 parts sand to 1 part Portland cement by volume. Dry ingredients occupy about 25% more than the finished pack, which this allows for.
Frequently asked questions
How thick should a shower pan deck mud bed be?
Three quarters of an inch minimum at the drain, sloping up at a quarter inch per foot toward the walls. On a four foot pan that puts the perimeter around one and three quarter inches.
What is the right consistency for deck mud?
Squeeze a handful: it should hold its shape without water running out and crumble slightly at the edges. Too wet and it slumps out of the slope you just troweled.
Can I use regular mortar instead?
No. Standard mortar is too wet and too rich in cement to hold a slope, and it shrinks and cracks in a thick bed.