Example Data Table
| Length |
Width |
Drain Offset |
Slope |
Drain Thickness |
Waste |
Target Mix |
| 5 ft |
3 ft |
2.5 ft, 1.5 ft |
0.25 in/ft |
1.25 in |
10% |
5:1 |
| 4 ft |
4 ft |
2 ft, 2 ft |
0.25 in/ft |
1.50 in |
12% |
5:1 |
| 6 ft |
3.5 ft |
3 ft, 1.75 ft |
0.30 in/ft |
1.25 in |
15% |
4.5:1 |
Formula Used
Area: length × width.
Farthest drain run: greatest distance from drain center to any corner.
Perimeter rise: farthest drain run × slope per foot.
Perimeter thickness: drain thickness + perimeter rise.
Average thickness: (drain thickness + perimeter thickness) ÷ 2.
Compacted volume: area × average thickness in feet.
Dry material volume: compacted volume × waste factor × dry factor.
Sand volume: dry volume × sand parts ÷ total parts.
Cement volume: dry volume × cement parts ÷ total parts.
Premix volume: dry volume × premix total parts ÷ target total parts.
How To Use This Calculator
Enter the shower floor length and width first. Choose the matching unit. Add the drain position from the left and bottom edges. Enter the minimum mud thickness at the drain. Add your required slope per foot. Keep waste above zero for cutting, packing, and jobsite loss.
Use the target mix fields for dry pack planning. A 5:1 mix means five parts sand and one part cement. Change densities, bag weights, yields, and prices when your local materials differ. Press calculate. The result appears above the form.
John Bridge Mud Planning Guide
What This Tool Estimates
This calculator helps estimate deck mud for a tiled shower pan. It uses floor size, drain location, slope, and drain thickness. The goal is a practical material plan before mixing begins. It gives compacted volume, dry volume, sand, cement, bags, and cost.
Why Drain Position Matters
A centered drain usually creates balanced mud depth. An offset drain changes the longest run. The farthest corner controls the perimeter height. This keeps the outer edge level while maintaining fall toward the drain. The calculator checks each corner and uses the longest distance.
Understanding Thickness
Deck mud volume depends on average thickness. The thin point sits near the drain. The thick point sits at the perimeter. The calculator averages those two depths. That method is useful for planning. Real pans may vary slightly because corners, curbs, benches, and notches change the shape.
Mix Options
Many installers use a dry pack blend with more sand than cement. The form allows any target ratio. A common planning value is five parts sand to one part cement. The separate method estimates loose sand and cement bags. The premix method estimates sand topping mix plus added sand.
Waste And Dry Factor
Waste covers spillage, bucket residue, low spots, and small corrections. The dry factor allows for packing and volume change. These fields make the estimate more flexible. Use a higher value when the floor is irregular. Use a smaller value when measurements are exact and access is easy.
Cost Planning
The result compares separate materials and a premix approach. Prices are only estimates. Local bag sizes and yields can differ. Change every price field before ordering. The tool rounds bag counts upward because partial bags are not practical on most jobs.
Best Use
Measure twice before entering values. Confirm the drain flange height. Check the required slope for your project. Review the farthest run and perimeter thickness carefully. Use the result as a planning guide, not a building code decision. When the project is structural or waterproofing critical, follow product instructions and local requirements.
FAQs
What is a John Bridge mud calculator?
It is a shower deck mud estimator inspired by tile pan planning. It estimates slope, volume, dry pack ingredients, bag counts, and cost from your floor measurements.
What mix ratio should I use?
A 5:1 sand to cement ratio is a common dry pack planning value. You can change the ratio in the form when your material instructions require another blend.
Why does the calculator use the farthest drain run?
The farthest run helps set the needed perimeter height. This allows the outer edge to remain level while preserving slope toward the drain.
What does dry material factor mean?
It adjusts compacted mud volume into estimated loose dry material. Packing, moisture, and handling can change final yield, so the factor adds planning flexibility.
Why are bag counts rounded upward?
You cannot usually buy or mix a precise fraction of a bag. Rounding upward helps prevent shortages during the mud bed placement.
Can I use meters or inches?
Yes. Choose feet, inches, or meters. The calculator converts the floor size and drain offsets into feet before calculating slope and volume.
Does this replace waterproofing instructions?
No. It only estimates mud material. Always follow drain, membrane, mortar, and tile product instructions for waterproofing and installation details.
Why compare premix and separate materials?
Some projects use sand and cement separately. Others modify sand topping mix with extra sand. Comparing both helps with budget and shopping decisions.