Add up piers of many heights on a slope.
⚙️Calculation Parameters
📊Calculated Output
How Sloped-Site Pier Quantity Calculator Works?
To total piers on a slope, the Sloped-Site Pier Quantity Calculator gives each pier its own height and sums the volumes. The process takes 4 steps.
Set the diameter
Enter the tube diameter used on every pier, or one diameter per pier, if sizes vary.
Enter each pier height
Type the height of each pier from the hole bottom to the beam line. Downhill piers are taller.
Use the slope shortcut
Enter the first height, the last height and the pier count. The calculator spaces the heights evenly between them.
Read the total
The calculator adds every pier into one volume and one bag count.
Sloped-Site Pier Quantity Calculator Formula
The Sloped-Site Pier Quantity Calculator sums cylinders with different heights.
Pier volume
Vᵢ = π × (D ÷ 24)² × (Hᵢ ÷ 12)Hᵢ is the height of pier i in inches.
Total
V = π × (D ÷ 24)² × ΣHᵢ ÷ 12With one diameter, only the summed height matters.
Even slope
Hᵢ = H₁ + (i − 1) × (Hₙ − H₁) ÷ (n − 1)Fills in heights on a uniform slope.
Worked example: 6 piers, 10 in tubes, 36 in to 76 in
- Step = (76 − 36) ÷ 5 = 8 in per pier
- ΣH = 36 + 44 + 52 + 60 + 68 + 76 = 336 in = 28.00 ft
- V = 0.5454 × 28.00 = 15.27 ft³ (0.566 yd³)
Sloped-Site Pier Quantity Calculator Conversion Table
The sloped-site conversion table lists 6 piers of 10 in (25 cm) diameter stepping down a slope in 8 in steps.
| Pier | Height | ft³ | yd³ | 80 lb bags |
|---|---|---|---|---|
| Pier 1 | 36 in (91 cm) | 1.636 | 0.0606 | 3 |
| Pier 2 | 44 in (112 cm) | 2.000 | 0.0741 | 4 |
| Pier 3 | 52 in (132 cm) | 2.363 | 0.0875 | 4 |
| Pier 4 | 60 in (152 cm) | 2.727 | 0.1010 | 5 |
| Pier 5 | 68 in (173 cm) | 3.091 | 0.1145 | 6 |
| Pier 6 | 76 in (193 cm) | 3.454 | 0.1279 | 6 |
| Total | 336 in | 15.27 | 0.566 | 26 |
The total row rounds bags once for all piers, which saves bags compared with summing the per-pier column.
What is Sloped-Site Pier Quantity Calculator?
A Sloped-Site Pier Quantity Calculator is a concrete calculator for rows of piers that share a top elevation but sit on falling ground, so every pier has a different height.
A deck beam stays level while the ground drops. On a 1-in-6 slope, piers 8 ft apart differ by 16 in of height. Using one average height hides the fact that the tallest piers need longer tubes, and the calculator lists each pier on its own.
The tool shows per-pier tube lengths, so the cut list and the concrete order come from the same numbers.
What are the uses of Sloped-Site Pier Quantity Calculator?
There are 4 main uses of the Sloped-Site Pier Quantity Calculator.
Hillside decks
Builders total piers stepping down a backyard slope.
Cabins on piers
Contractors size piers for level floors on uneven lots.
Boardwalks
Crews total piers along a walkway crossing a ditch or bank.
Tube cut lists
Installers cut each tube to its own pier height.
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