Concrete Form Tubes: Round Footings & Pier Guide (2026)
Concrete form tubes, commonly known as Sonotubes, are heavy-duty cardboard cylinders for creating round concrete footings and piers. They provide a clean, uniform pour for deck posts, sign foundations, and structural columns. Available in diameters from 6 to 24 inches and lengths up to 12 feet.
Key Features
- Smooth round finish; Diameters 6-24 inches; Moisture-resistant outer layer; Easy to cut to length; Strips away after cure
Specifications
Applications
- Deck footings; Fence post footings; Structural piers; Sign foundations; Column forms
Installation Overview
Dig to frost depth. Place tube on compacted gravel. Level and brace. Insert rebar. Pour concrete to top, consolidate. Strip tube after 24-48 hours or leave in place.
Pros & Cons
Pros
- ✓ Professional round finish; Easy setup; Many sizes available; Keeps soil out of pour; Reusable bracing
Cons
- ✗ Single use only; Must be braced plumb; Can collapse if waterlogged; Awkward to transport; Needs separate footing pad
Top Brands
Code Requirements
Footing diameter and depth per IRC R403 and local frost-depth requirements. Must bear on undisturbed soil below frost line. Rebar per engineer or code.
Buying Tips
Buy tubes at least 6 inches longer than frost depth for trimming. Moisture-resistant premium tubes are worth it in wet soil.
Frequently Asked Questions
Related Guides
Heat Pump Guide: Types, Cost & How They Work
Heat and cool your home efficiently with one system.
Read articleAir Conditioning Guide: Types, Cost & Efficiency
Stay cool and save money on cooling.
Read articleWater Heater Guide: Types, Cost & Replacement
Choose the best water heater for your home.
Read article