Concrete per sonotube size
| Diameter | cu ft per ft | cu ft in 4 ft | 80 lb bags in 4 ft |
|---|---|---|---|
| 6 in | 0.20 | 0.79 | 2 |
| 8 in | 0.35 | 1.40 | 3 |
| 10 in | 0.55 | 2.18 | 4 |
| 12 in | 0.79 | 3.14 | 6 |
| 14 in | 1.07 | 4.28 | 8 |
| 16 in | 1.40 | 5.59 | 10 |
| 18 in | 1.77 | 7.07 | 12 |
| 24 in | 3.14 | 12.57 | 21 |
How to calculate concrete for a round form
If the tube sits on a wider footing, such as a bell-shaped base or a square pad, work that out separately with the footing calculator and add the two together.
Tips for pouring sonotubes
- Brace each tube plumb before pouring. Wet concrete can push a loose tube off line.
- Pour in stages and rod or tap the sides to remove air pockets.
- Set anchor bolts or post bases while the concrete is still wet.
Concrete per tube form size
| Diameter | m³ per metre | m³ in 1.2 m | 25 kg bags in 1.2 m |
|---|---|---|---|
| 15 cm | 0.018 | 0.021 | 2 |
| 20 cm | 0.031 | 0.038 | 4 |
| 25 cm | 0.049 | 0.059 | 6 |
| 30 cm | 0.071 | 0.085 | 8 |
| 35 cm | 0.096 | 0.115 | 10 |
| 40 cm | 0.126 | 0.151 | 13 |
| 45 cm | 0.159 | 0.191 | 17 |
| 60 cm | 0.283 | 0.339 | 29 |
How to calculate concrete for a round form
If the tube sits on a wider footing, such as a bell-shaped base or a square pad, work that out separately with the footing calculator and add the two together.
Tips for pouring tube forms
- Brace each tube plumb before pouring. Wet concrete can push a loose tube off line.
- Pour in stages and rod or tap the sides to remove air pockets.
- Set anchor bolts or post bases while the concrete is still wet.
Common questions
How many bags of concrete fill a 12 inch sonotube?
A 12 in tube holds about 0.79 cubic feet per foot of height. A 4 ft tube needs about 6 bags of 80 lb.
How many bags of concrete fill a 30 cm tube form?
A 30 cm tube holds about 0.071 m³ per metre of height. A 1.2 m tube needs about 8 bags of 25 kg.
How many bags for an 8 inch sonotube?
An 8 in tube holds about 0.35 cubic feet per foot. A 4 ft tube needs about 3 bags of 80 lb.
How many bags for a 20 cm tube form?
A 20 cm tube holds about 0.031 m³ per metre. A 1.2 m tube needs about 4 bags of 25 kg.
What size sonotube do I need for a deck?
Deck footings commonly use 8 to 12 in tubes, but the right size depends on the deck's load and your soil. Your local building code or permit drawings will set the minimum.
What size tube form do I need for a deck?
Deck footings commonly use 20 to 30 cm tubes, but the right size depends on the deck's load and your soil. Your local building rules or plans will set the minimum.